search.js

// ignore-tidy-filelength
/* global addClass, getNakedUrl, getVar, nonnull, getSettingValue */
/* global onEachLazy, removeClass, searchState, browserSupportsHistoryApi */

"use strict";

/**
 * @param {stringdex.Stringdex} Stringdex
 * @param {typeof stringdex.RoaringBitmap} RoaringBitmap
 * @param {stringdex.Hooks} hooks
 */
const initSearch = async function(Stringdex, RoaringBitmap, hooks) {

// polyfill
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSpliced
if (!Array.prototype.toSpliced) {
    // Can't use arrow functions, because we want `this`
    Array.prototype.toSpliced = function() {
        const me = this.slice();
        // @ts-expect-error
        Array.prototype.splice.apply(me, arguments);
        return me;
    };
}

/**
 *
 * @template T
 * @param {Iterable<T>} arr
 * @param {function(T): Promise<any>} func
 * @param {function(T): boolean} funcBtwn
 */
async function onEachBtwnAsync(arr, func, funcBtwn) {
    let skipped = true;
    for (const value of arr) {
        if (!skipped) {
            funcBtwn(value);
        }
        skipped = await func(value);
    }
}

/**
 * Allow the browser to redraw.
 * @returns {Promise<void>}
 */
const yieldToBrowser = typeof window !== "undefined" && window.requestIdleCallback ?
    function() {
        return new Promise((resolve, _reject) => {
            window.requestIdleCallback(resolve);
        });
    } :
    function() {
        return new Promise((resolve, _reject) => {
            setTimeout(resolve, 0);
        });
    };

/**
 * Promise-based timer wrapper.
 * @param {number} ms
 * @returns {Promise<void>}
 */
const timeout = function(ms) {
    return new Promise((resolve, _reject) => {
        setTimeout(resolve, ms);
    });
};

if (!Promise.withResolvers) {
    /**
     * Polyfill
     * @template T
     * @returns {{
            "promise": Promise<T>,
            "resolve": (function(T): void),
            "reject": (function(any): void)
        }}
     */
    Promise.withResolvers = () => {
        let resolve, reject;
        const promise = new Promise((res, rej) => {
          resolve = res;
          reject = rej;
        });
        // @ts-expect-error
        return {promise, resolve, reject};
    };
}

// ==================== Core search logic begin ====================
// This mapping table should match the discriminants of
// `rustdoc::formats::item_type::ItemType` type in Rust.
const itemTypes = [
    "keyword",
    "primitive",
    "mod",
    "externcrate",
    "import",
    "struct", // 5
    "enum",
    "fn",
    "type",
    "static",
    "trait", // 10
    "impl",
    "tymethod",
    "method",
    "structfield",
    "variant", // 15
    "macro",
    "associatedtype",
    "constant",
    "associatedconstant",
    "union", // 20
    "foreigntype",
    "existential",
    "attr",
    "derive",
    "traitalias", // 25
    "generic",
];

// used for special search precedence
/** @type {rustdoc.ItemType} */
const TY_PRIMITIVE = 1;
/** @type {rustdoc.ItemType} */
const TY_GENERIC = 26;
/** @type {rustdoc.ItemType} */
const TY_IMPORT = 4;
/** @type {rustdoc.ItemType} */
const TY_TRAIT = 10;
/** @type {rustdoc.ItemType} */
const TY_FN = 7;
/** @type {rustdoc.ItemType} */
const TY_METHOD = 13;
/** @type {rustdoc.ItemType} */
const TY_TYMETHOD = 12;
/** @type {rustdoc.ItemType} */
const TY_ASSOCTYPE = 17;
const ROOT_PATH = typeof window !== "undefined" ? window.rootPath : "../";

// Hard limit on how deep to recurse into generics when doing type-driven search.
// This needs limited, partially because
// a search for `Ty` shouldn't match `WithInfcx<ParamEnvAnd<Vec<ConstTy<Interner<Ty=Ty>>>>>`,
// but mostly because this is the simplest and most principled way to limit the number
// of permutations we need to check.
const UNBOXING_LIMIT = 5;

// used for search query verification
const REGEX_IDENT = /\p{ID_Start}\p{ID_Continue}*|_\p{ID_Continue}+/uy;
const REGEX_INVALID_TYPE_FILTER = /[^a-z]/ui;

const MAX_RESULTS = 200;
const NO_TYPE_FILTER = -1;

/**
 * The [edit distance] is a metric for measuring the difference between two strings.
 *
 * [edit distance]: https://en.wikipedia.org/wiki/Edit_distance
 */

/*
 * This function was translated, mostly line-for-line, from
 * https://github.com/rust-lang/rust/blob/ff4b772f805ec1e/compiler/rustc_span/src/edit_distance.rs
 *
 * The current implementation is the restricted Damerau-Levenshtein algorithm. It is restricted
 * because it does not permit modifying characters that have already been transposed. The specific
 * algorithm should not matter to the caller of the methods, which is why it is not noted in the
 * documentation.
 */
const editDistanceState = {
    /**
     * @type {number[]}
     */
    current: [],
    /**
     * @type {number[]}
     */
    prev: [],
    /**
     * @type {number[]}
     */
    prevPrev: [],
    /**
     * @param {string} a
     * @param {string} b
     * @param {number} limit
     * @returns
     */
    calculate: function calculate(a, b, limit) {
        // Ensure that `b` is the shorter string, minimizing memory use.
        if (a.length < b.length) {
            const aTmp = a;
            a = b;
            b = aTmp;
        }

        const minDist = a.length - b.length;
        // If we know the limit will be exceeded, we can return early.
        if (minDist > limit) {
            return limit + 1;
        }

        // Strip common prefix.
        // We know that `b` is the shorter string, so we don't need to check
        // `a.length`.
        while (b.length > 0 && b[0] === a[0]) {
            a = a.substring(1);
            b = b.substring(1);
        }
        // Strip common suffix.
        while (b.length > 0 && b[b.length - 1] === a[a.length - 1]) {
            a = a.substring(0, a.length - 1);
            b = b.substring(0, b.length - 1);
        }

        // If either string is empty, the distance is the length of the other.
        // We know that `b` is the shorter string, so we don't need to check `a`.
        if (b.length === 0) {
            return minDist;
        }

        const aLength = a.length;
        const bLength = b.length;

        for (let i = 0; i <= bLength; ++i) {
            this.current[i] = 0;
            this.prev[i] = i;
            this.prevPrev[i] = Number.MAX_VALUE;
        }

        // row by row
        for (let i = 1; i <= aLength; ++i) {
            this.current[0] = i;
            const aIdx = i - 1;

            // column by column
            for (let j = 1; j <= bLength; ++j) {
                const bIdx = j - 1;

                // There is no cost to substitute a character with itself.
                const substitutionCost = a[aIdx] === b[bIdx] ? 0 : 1;

                this.current[j] = Math.min(
                    // deletion
                    this.prev[j] + 1,
                    // insertion
                    this.current[j - 1] + 1,
                    // substitution
                    this.prev[j - 1] + substitutionCost,
                );

                if ((i > 1) && (j > 1) && (a[aIdx] === b[bIdx - 1]) && (a[aIdx - 1] === b[bIdx])) {
                    // transposition
                    this.current[j] = Math.min(
                        this.current[j],
                        this.prevPrev[j - 2] + 1,
                    );
                }
            }

            // Rotate the buffers, reusing the memory
            const prevPrevTmp = this.prevPrev;
            this.prevPrev = this.prev;
            this.prev = this.current;
            this.current = prevPrevTmp;
        }

        // `prev` because we already rotated the buffers.
        const distance = this.prev[bLength];
        return distance <= limit ? distance : (limit + 1);
    },
};

/**
 * @param {string} a
 * @param {string} b
 * @param {number} limit
 * @returns
 */
function editDistance(a, b, limit) {
    return editDistanceState.calculate(a, b, limit);
}

/**
 * @param {string} c
 * @returns {boolean}
 */
function isEndCharacter(c) {
    return "=,>-])".indexOf(c) !== -1;
}

/**
 * Same thing as ItemType::is_fn_like in item_type.rs
 *
 * @param {rustdoc.ItemType} ty
 * @returns
 */
function isFnLikeTy(ty) {
    return ty === TY_FN || ty === TY_METHOD || ty === TY_TYMETHOD;
}

/**
 * Returns `true` if the given `c` character is a separator.
 *
 * @param {string} c
 *
 * @return {boolean}
 */
function isSeparatorCharacter(c) {
    return c === "," || c === "=";
}

/**
 * Returns `true` if the current parser position is starting with "->".
 *
 * @param {rustdoc.ParserState} parserState
 *
 * @return {boolean}
 */
function isReturnArrow(parserState) {
    return parserState.userQuery.slice(parserState.pos, parserState.pos + 2) === "->";
}

/**
 * Increase current parser position until it doesn't find a whitespace anymore.
 *
 * @param {rustdoc.ParserState} parserState
 */
function skipWhitespace(parserState) {
    while (parserState.pos < parserState.userQuery.length) {
        const c = parserState.userQuery[parserState.pos];
        if (c !== " ") {
            break;
        }
        parserState.pos += 1;
    }
}

/**
 * Returns `true` if the previous character is `lookingFor`.
 *
 * @param {rustdoc.ParserState} parserState
 * @param {String} lookingFor
 *
 * @return {boolean}
 */
function prevIs(parserState, lookingFor) {
    let pos = parserState.pos;
    while (pos > 0) {
        const c = parserState.userQuery[pos - 1];
        if (c === lookingFor) {
            return true;
        } else if (c !== " ") {
            break;
        }
        pos -= 1;
    }
    return false;
}

/**
 * Returns `true` if the last element in the `elems` argument has generics.
 *
 * @param {Array<rustdoc.ParserQueryElement>} elems
 * @param {rustdoc.ParserState} parserState
 *
 * @return {boolean}
 */
function isLastElemGeneric(elems, parserState) {
    return (elems.length > 0 && elems[elems.length - 1].generics.length > 0) ||
        prevIs(parserState, ">");
}

/**
 *
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {rustdoc.ParserState} parserState
 * @param {rustdoc.ParserQueryElement[]} elems
 * @param {boolean} isInGenerics
 */
function getFilteredNextElem(query, parserState, elems, isInGenerics) {
    const start = parserState.pos;
    if (parserState.userQuery[parserState.pos] === ":" && !isPathStart(parserState)) {
        throw ["Expected type filter before ", ":"];
    }
    getNextElem(query, parserState, elems, isInGenerics);
    if (parserState.userQuery[parserState.pos] === ":" && !isPathStart(parserState)) {
        if (parserState.typeFilter !== null) {
            throw [
                "Unexpected ",
                ":",
                " (expected path after type filter ",
                parserState.typeFilter + ":",
                ")",
            ];
        }
        if (elems.length === 0) {
            throw ["Expected type filter before ", ":"];
        } else if (query.literalSearch) {
            throw ["Cannot use quotes on type filter"];
        }
        // The type filter doesn't count as an element since it's a modifier.
        const typeFilterElem = elems.pop();
        checkExtraTypeFilterCharacters(start, parserState);
        // typeFilterElem is not undefined. If it was, the elems.length check would have fired.
        // @ts-expect-error
        parserState.typeFilter = typeFilterElem.normalizedPathLast;
        parserState.pos += 1;
        parserState.totalElems -= 1;
        query.literalSearch = false;
        getNextElem(query, parserState, elems, isInGenerics);
    }
}

/**
 * This function parses the next query element until it finds `endChar`,
 * calling `getNextElem` to collect each element.
 *
 * If there is no `endChar`, this function will implicitly stop at the end
 * without raising an error.
 *
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {rustdoc.ParserState} parserState
 * @param {Array<rustdoc.ParserQueryElement>} elems
 *     - This is where the new {QueryElement} will be added.
 * @param {string} endChar - This function will stop when it'll encounter this
 *                           character.
 * @returns {{foundSeparator: boolean}}
 */
function getItemsBefore(query, parserState, elems, endChar) {
    let foundStopChar = true;
    let foundSeparator = false;

    // If this is a generic, keep the outer item's type filter around.
    const oldTypeFilter = parserState.typeFilter;
    parserState.typeFilter = null;
    const oldIsInBinding = parserState.isInBinding;
    parserState.isInBinding = null;

    // ML-style Higher Order Function notation
    //
    // a way to search for any closure or fn pointer regardless of
    // which closure trait is used
    //
    // Looks like this:
    //
    //     `option<t>, (t -> u) -> option<u>`
    //                  ^^^^^^
    //
    // The Rust-style closure notation is implemented in getNextElem
    let hofParameters = null;

    let extra = "";
    if (endChar === ">") {
        extra = "<";
    } else if (endChar === "]") {
        extra = "[";
    } else if (endChar === ")") {
        extra = "(";
    } else if (endChar === "") {
        extra = "->";
    } else {
        extra = endChar;
    }

    while (parserState.pos < parserState.length) {
        const c = parserState.userQuery[parserState.pos];
        if (c === endChar) {
            if (parserState.isInBinding) {
                throw ["Unexpected ", endChar, " after ", "="];
            }
            break;
        } else if (endChar !== "" && isReturnArrow(parserState)) {
            // ML-style HOF notation only works when delimited in something,
            // otherwise a function arrow starts the return type of the top
            if (parserState.isInBinding) {
                throw ["Unexpected ", "->", " after ", "="];
            }
            hofParameters = [...elems];
            elems.length = 0;
            parserState.pos += 2;
            foundStopChar = true;
            foundSeparator = false;
            continue;
        } else if (c === " ") {
            parserState.pos += 1;
            continue;
        } else if (isSeparatorCharacter(c)) {
            parserState.pos += 1;
            foundStopChar = true;
            foundSeparator = true;
            continue;
        } else if (c === ":" && isPathStart(parserState)) {
            throw ["Unexpected ", "::", ": paths cannot start with ", "::"];
        } else if (isEndCharacter(c)) {
            throw ["Unexpected ", c, " after ", extra];
        }
        if (!foundStopChar) {
            /** @type {string[]} */
            let extra = [];
            if (isLastElemGeneric(query.elems, parserState)) {
                extra = [" after ", ">"];
            } else if (prevIs(parserState, "\"")) {
                throw ["Cannot have more than one element if you use quotes"];
            }
            if (endChar !== "") {
                throw [
                    "Expected ",
                    ",",
                    ", ",
                    "=",
                    ", or ",
                    endChar,
                    ...extra,
                    ", found ",
                    c,
                ];
            }
            throw [
                "Expected ",
                ",",
                " or ",
                "=",
                ...extra,
                ", found ",
                c,
            ];
        }
        const posBefore = parserState.pos;
        getFilteredNextElem(query, parserState, elems, endChar !== "");
        if (endChar !== "" && parserState.pos >= parserState.length) {
            throw ["Unclosed ", extra];
        }
        // This case can be encountered if `getNextElem` encountered a "stop character"
        // right from the start. For example if you have `,,` or `<>`. In this case,
        // we simply move up the current position to continue the parsing.
        if (posBefore === parserState.pos) {
            parserState.pos += 1;
        }
        foundStopChar = false;
    }
    if (parserState.pos >= parserState.length && endChar !== "") {
        throw ["Unclosed ", extra];
    }
    // We are either at the end of the string or on the `endChar` character, let's move
    // forward in any case.
    parserState.pos += 1;

    if (hofParameters) {
        // Commas in a HOF don't cause wrapping parens to become a tuple.
        // If you want a one-tuple with a HOF in it, write `((a -> b),)`.
        foundSeparator = false;
        // HOFs can't have directly nested bindings.
        if ([...elems, ...hofParameters].some(x => x.bindingName)
            || parserState.isInBinding) {
            throw ["Unexpected ", "=", " within ", "->"];
        }
        // HOFs are represented the same way closures are.
        // The arguments are wrapped in a tuple, and the output
        // is a binding, even though the compiler doesn't technically
        // represent fn pointers that way.
        const hofElem = makePrimitiveElement("->", {
            generics: hofParameters,
            bindings: new Map([["output", [...elems]]]),
            typeFilter: null,
        });
        elems.length = 0;
        elems[0] = hofElem;
    }

    parserState.typeFilter = oldTypeFilter;
    parserState.isInBinding = oldIsInBinding;

    return { foundSeparator };
}

/**
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {rustdoc.ParserState} parserState
 * @param {Array<rustdoc.ParserQueryElement>} elems
 *     - This is where the new {QueryElement} will be added.
 * @param {boolean} isInGenerics
 */
function getNextElem(query, parserState, elems, isInGenerics) {
    /** @type {rustdoc.ParserQueryElement[]} */
    const generics = [];

    /** @type {function(string, string): void} */
    const handleRefOrPtr = (chr, name) => {
            if (parserState.typeFilter !== null && parserState.typeFilter !== "primitive") {
            throw [
                "Invalid search type: primitive ",
                chr,
                " and ",
                parserState.typeFilter,
                " both specified",
            ];
        }
        parserState.typeFilter = null;
        parserState.pos += 1;
        let c = parserState.userQuery[parserState.pos];
        while (c === " " && parserState.pos < parserState.length) {
            parserState.pos += 1;
            c = parserState.userQuery[parserState.pos];
        }
        const generics = [];
        const pos = parserState.pos;
        if (parserState.userQuery.slice(pos, pos + 3) === "mut") {
            generics.push(makePrimitiveElement("mut", { typeFilter: "keyword" }));
            parserState.pos += 3;
            c = parserState.userQuery[parserState.pos];
        } else if (chr === "*" && parserState.userQuery.slice(pos, pos + 5) === "const") {
            // make *const T parse the same as *T
            parserState.pos += 5;
            c = parserState.userQuery[parserState.pos];
        }
        while (c === " " && parserState.pos < parserState.length) {
            parserState.pos += 1;
            c = parserState.userQuery[parserState.pos];
        }
        if (!isEndCharacter(c) && parserState.pos < parserState.length) {
            getFilteredNextElem(query, parserState, generics, isInGenerics);
        }
        elems.push(makePrimitiveElement(name, { generics }));
    };

    skipWhitespace(parserState);
    let start = parserState.pos;
    let end;
    if ("[(".indexOf(parserState.userQuery[parserState.pos]) !== -1) {
        let endChar = ")";
        let name = "()";
        let friendlyName = "tuple";

        if (parserState.userQuery[parserState.pos] === "[") {
            endChar = "]";
            name = "[]";
            friendlyName = "slice";
        }
        parserState.pos += 1;
        const { foundSeparator } = getItemsBefore(query, parserState, generics, endChar);
        const typeFilter = parserState.typeFilter;
        const bindingName = parserState.isInBinding;
        parserState.typeFilter = null;
        parserState.isInBinding = null;
        for (const gen of generics) {
            if (gen.bindingName !== null) {
                throw ["Type parameter ", "=", ` cannot be within ${friendlyName} `, name];
            }
        }
        if (name === "()" && !foundSeparator && generics.length === 1
            && typeFilter === null) {
            elems.push(generics[0]);
        } else if (name === "()" && generics.length === 1 && generics[0].name === "->") {
            // `primitive:(a -> b)` parser to `primitive:"->"<output=b, (a,)>`
            // not `primitive:"()"<"->"<output=b, (a,)>>`
            generics[0].typeFilter = typeFilter;
            elems.push(generics[0]);
        } else {
            if (typeFilter !== null && typeFilter !== "primitive") {
                throw [
                    "Invalid search type: primitive ",
                    name,
                    " and ",
                    typeFilter,
                    " both specified",
                ];
            }
            parserState.totalElems += 1;
            if (isInGenerics) {
                parserState.genericsElems += 1;
            }
            elems.push(makePrimitiveElement(name, { bindingName, generics }));
        }
    } else if (parserState.userQuery[parserState.pos] === "&") {
        handleRefOrPtr("&", "reference");
    } else if (parserState.userQuery[parserState.pos] === "*") {
        handleRefOrPtr("*", "pointer");
    } else {
        const isStringElem = parserState.userQuery[start] === "\"";
        // We handle the strings on their own mostly to make code easier to follow.
        if (isStringElem) {
            start += 1;
            getStringElem(query, parserState, isInGenerics);
            end = parserState.pos - 1;
        } else {
            end = getIdentEndPosition(parserState);
        }
        if (parserState.pos < parserState.length &&
            parserState.userQuery[parserState.pos] === "<"
        ) {
            if (start >= end) {
                throw ["Found generics without a path"];
            }
            parserState.pos += 1;
            getItemsBefore(query, parserState, generics, ">");
        } else if (parserState.pos < parserState.length &&
            parserState.userQuery[parserState.pos] === "("
        ) {
            if (start >= end) {
                throw ["Found generics without a path"];
            }
            if (parserState.isInBinding) {
                throw ["Unexpected ", "(", " after ", "="];
            }
            parserState.pos += 1;
            const typeFilter = parserState.typeFilter;
            parserState.typeFilter = null;
            getItemsBefore(query, parserState, generics, ")");
            skipWhitespace(parserState);
            if (isReturnArrow(parserState)) {
                parserState.pos += 2;
                skipWhitespace(parserState);
                getFilteredNextElem(query, parserState, generics, isInGenerics);
                generics[generics.length - 1].bindingName = makePrimitiveElement("output");
            } else {
                generics.push(makePrimitiveElement(null, {
                    bindingName: makePrimitiveElement("output"),
                    typeFilter: null,
                }));
            }
            parserState.typeFilter = typeFilter;
        }
        if (isStringElem) {
            skipWhitespace(parserState);
        }
        if (start >= end && generics.length === 0) {
            return;
        }
        if (parserState.userQuery[parserState.pos] === "=") {
            if (parserState.isInBinding) {
                throw ["Cannot write ", "=", " twice in a binding"];
            }
            if (!isInGenerics) {
                throw ["Type parameter ", "=", " must be within generics list"];
            }
            const name = parserState.userQuery.slice(start, end).trim();
            if (name === "!") {
                throw ["Type parameter ", "=", " key cannot be ", "!", " never type"];
            }
            if (name.includes("!")) {
                throw ["Type parameter ", "=", " key cannot be ", "!", " macro"];
            }
            if (name.includes("::")) {
                throw ["Type parameter ", "=", " key cannot contain ", "::", " path"];
            }
            if (name.includes(":")) {
                throw ["Type parameter ", "=", " key cannot contain ", ":", " type"];
            }
            parserState.isInBinding = { name, generics };
        } else {
            elems.push(
                createQueryElement(
                    query,
                    parserState,
                    parserState.userQuery.slice(start, end),
                    generics,
                    isInGenerics,
                ),
            );
        }
    }
}

/**
 * Checks that the type filter doesn't have unwanted characters like `<>` (which are ignored
 * if empty).
 *
 * @param {number} start
 * @param {rustdoc.ParserState} parserState
 */
function checkExtraTypeFilterCharacters(start, parserState) {
    const query = parserState.userQuery.slice(start, parserState.pos).trim();

    const match = query.match(REGEX_INVALID_TYPE_FILTER);
    if (match) {
        throw [
            "Unexpected ",
            match[0],
            " in type filter (before ",
            ":",
            ")",
        ];
    }
}

/**
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {rustdoc.ParserState} parserState
 * @param {string} name - Name of the query element.
 * @param {Array<rustdoc.ParserQueryElement>} generics - List of generics of this query element.
 * @param {boolean} isInGenerics
 *
 * @return {rustdoc.ParserQueryElement} - The newly created `QueryElement`.
 */
function createQueryElement(query, parserState, name, generics, isInGenerics) {
    const path = name.trim();
    if (path.length === 0 && generics.length === 0) {
        throw ["Unexpected ", parserState.userQuery[parserState.pos]];
    }
    if (query.literalSearch && parserState.totalElems - parserState.genericsElems > 0) {
        throw ["Cannot have more than one element if you use quotes"];
    }
    const typeFilter = parserState.typeFilter;
    parserState.typeFilter = null;
    if (name.trim() === "!") {
        if (typeFilter !== null && typeFilter !== "primitive") {
            throw [
                "Invalid search type: primitive never type ",
                "!",
                " and ",
                typeFilter,
                " both specified",
            ];
        }
        if (generics.length !== 0) {
            throw [
                "Never type ",
                "!",
                " does not accept generic parameters",
            ];
        }
        const bindingName = parserState.isInBinding;
        parserState.isInBinding = null;
        return makePrimitiveElement("never", { bindingName });
    }
    const quadcolon = /::\s*::/.exec(path);
    if (path.startsWith("::")) {
        throw ["Paths cannot start with ", "::"];
    } else if (quadcolon !== null) {
        throw ["Unexpected ", quadcolon[0]];
    }
    const pathSegments = path.split(/(?:::\s*)|(?:\s+(?:::\s*)?)/).map(x => x.toLowerCase());
    // In case we only have something like `<p>`, there is no name.
    if (pathSegments.length === 0
        || (pathSegments.length === 1 && pathSegments[0] === "")) {
        if (generics.length > 0 || prevIs(parserState, ">")) {
            throw ["Found generics without a path"];
        } else {
            throw ["Unexpected ", parserState.userQuery[parserState.pos]];
        }
    }
    for (const [i, pathSegment] of pathSegments.entries()) {
        if (pathSegment === "!") {
            if (i !== 0) {
                throw ["Never type ", "!", " is not associated item"];
            }
            pathSegments[i] = "never";
        }
    }
    parserState.totalElems += 1;
    if (isInGenerics) {
        parserState.genericsElems += 1;
    }
    const bindingName = parserState.isInBinding;
    parserState.isInBinding = null;
    const bindings = new Map();
    const pathLast = pathSegments[pathSegments.length - 1];
    return {
        name: name.trim(),
        id: null,
        fullPath: pathSegments,
        pathWithoutLast: pathSegments.slice(0, pathSegments.length - 1),
        pathLast,
        normalizedPathLast: pathLast.replace(/_/g, ""),
        generics: generics.filter(gen => {
            // Syntactically, bindings are parsed as generics,
            // but the query engine treats them differently.
            if (gen.bindingName !== null && gen.bindingName.name !== null) {
                if (gen.name !== null) {
                    gen.bindingName.generics.unshift(gen);
                }
                bindings.set(
                    gen.bindingName.name.toLowerCase().replace(/_/g, ""),
                    gen.bindingName.generics,
                );
                return false;
            }
            return true;
        }),
        bindings,
        typeFilter,
        bindingName,
    };
}

/**
 *
 * @param {string|null} name
 * @param {rustdoc.ParserQueryElementFields=} extra
 * @returns {rustdoc.ParserQueryElement}
 */
function makePrimitiveElement(name, extra) {
    return Object.assign({
        name,
        id: null,
        fullPath: [name],
        pathWithoutLast: [],
        pathLast: name,
        normalizedPathLast: name,
        generics: [],
        bindings: new Map(),
        typeFilter: "primitive",
        bindingName: null,
    }, extra);
}

/**
 * If we encounter a `"`, then we try to extract the string
 * from it until we find another `"`.
 *
 * This function will throw an error in the following cases:
 * * There is already another string element.
 * * We are parsing a generic argument.
 * * There is more than one element.
 * * There is no closing `"`.
 *
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {rustdoc.ParserState} parserState
 * @param {boolean} isInGenerics
 */
function getStringElem(query, parserState, isInGenerics) {
    if (isInGenerics) {
        throw ["Unexpected ", "\"", " in generics"];
    } else if (query.literalSearch) {
        throw ["Cannot have more than one literal search element"];
    } else if (parserState.totalElems - parserState.genericsElems > 0) {
        throw ["Cannot use literal search when there is more than one element"];
    }
    parserState.pos += 1;
    const start = parserState.pos;
    const end = getIdentEndPosition(parserState);
    if (parserState.pos >= parserState.length) {
        throw ["Unclosed ", "\""];
    } else if (parserState.userQuery[end] !== "\"") {
        throw ["Unexpected ", parserState.userQuery[end], " in a string element"];
    } else if (start === end) {
        throw ["Cannot have empty string element"];
    }
    // To skip the quote at the end.
    parserState.pos += 1;
    query.literalSearch = true;
}

/**
 * This function goes through all characters until it reaches an invalid ident
 * character or the end of the query. It returns the position of the last
 * character of the ident.
 *
 * @param {rustdoc.ParserState} parserState
 *
 * @return {number}
 */
function getIdentEndPosition(parserState) {
    let afterIdent = consumeIdent(parserState);
    let end = parserState.pos;
    let macroExclamation = -1;
    while (parserState.pos < parserState.length) {
        const c = parserState.userQuery[parserState.pos];
        if (c === "!") {
            if (macroExclamation !== -1) {
                throw ["Cannot have more than one ", "!", " in an ident"];
            } else if (parserState.pos + 1 < parserState.length) {
                const pos = parserState.pos;
                parserState.pos++;
                const beforeIdent = consumeIdent(parserState);
                parserState.pos = pos;
                if (beforeIdent) {
                    throw ["Unexpected ", "!", ": it can only be at the end of an ident"];
                }
            }
            if (afterIdent) macroExclamation = parserState.pos;
        } else if (isPathSeparator(c)) {
            if (c === ":") {
                if (!isPathStart(parserState)) {
                    break;
                }
                // Skip current ":".
                parserState.pos += 1;
            } else {
                while (parserState.pos + 1 < parserState.length) {
                    const next_c = parserState.userQuery[parserState.pos + 1];
                    if (next_c !== " ") {
                        break;
                    }
                    parserState.pos += 1;
                }
            }
            if (macroExclamation !== -1) {
                throw ["Cannot have associated items in macros"];
            }
        } else if (
            c === "[" ||
            c === "(" ||
            isEndCharacter(c) ||
            isSpecialStartCharacter(c) ||
            isSeparatorCharacter(c)
        ) {
            break;
        } else if (parserState.pos > 0) {
            throw ["Unexpected ", c, " after ", parserState.userQuery[parserState.pos - 1],
                " (not a valid identifier)"];
        } else {
            throw ["Unexpected ", c, " (not a valid identifier)"];
        }
        parserState.pos += 1;
        afterIdent = consumeIdent(parserState);
        end = parserState.pos;
    }
    if (macroExclamation !== -1) {
        if (parserState.typeFilter === null) {
            parserState.typeFilter = "macro";
        } else if (parserState.typeFilter !== "macro") {
            throw [
                "Invalid search type: macro ",
                "!",
                " and ",
                parserState.typeFilter,
                " both specified",
            ];
        }
        end = macroExclamation;
    }
    return end;
}

/**
 * @param {string} c
 * @returns
 */
function isSpecialStartCharacter(c) {
    return "<\"".indexOf(c) !== -1;
}

/**
 * Returns `true` if the current parser position is starting with "::".
 *
 * @param {rustdoc.ParserState} parserState
 *
 * @return {boolean}
 */
function isPathStart(parserState) {
    return parserState.userQuery.slice(parserState.pos, parserState.pos + 2) === "::";
}

/**
 * If the current parser position is at the beginning of an identifier,
 * move the position to the end of it and return `true`. Otherwise, return `false`.
 *
 * @param {rustdoc.ParserState} parserState
 *
 * @return {boolean}
 */
function consumeIdent(parserState) {
    REGEX_IDENT.lastIndex = parserState.pos;
    const match = parserState.userQuery.match(REGEX_IDENT);
    if (match) {
        parserState.pos += match[0].length;
        return true;
    }
    return false;
}

/**
 * Returns `true` if the given `c` character is a path separator. For example
 * `:` in `a::b` or a whitespace in `a b`.
 *
 * @param {string} c
 *
 * @return {boolean}
 */
function isPathSeparator(c) {
    return c === ":" || c === " ";
}

/**
 * @template T
 */
class VlqHexDecoder {
    /**
     * @param {string} string
     * @param {function(rustdoc.VlqData): T} cons
     */
    constructor(string, cons) {
        this.string = string;
        this.cons = cons;
        this.offset = 0;
        this.elemCount = 0;
        /** @type {T[]} */
        this.backrefQueue = [];
    }
    /**
     * call after consuming `{`
     * @returns {rustdoc.VlqData[]}
     */
    decodeList() {
        let c = this.string.charCodeAt(this.offset);
        const ret = [];
        while (c !== 125) { // 125 = "}"
            ret.push(this.decode());
            c = this.string.charCodeAt(this.offset);
        }
        this.offset += 1; // eat cb
        return ret;
    }
    /**
     * consumes and returns a list or integer
     * @returns {rustdoc.VlqData}
     */
    decode() {
        let n = 0;
        let c = this.string.charCodeAt(this.offset);
        if (c === 123) { // 123 = "{"
            this.offset += 1;
            return this.decodeList();
        }
        while (c < 96) { // 96 = "`"
            n = (n << 4) | (c & 0xF);
            this.offset += 1;
            c = this.string.charCodeAt(this.offset);
        }
        // last character >= la
        n = (n << 4) | (c & 0xF);
        const [sign, value] = [n & 1, n >> 1];
        this.offset += 1;
        this.elemCount += 1;
        return sign ? -value : value;
    }
    /**
     * @returns {T}
     */
    next() {
        const c = this.string.charCodeAt(this.offset);
        // sixteen characters after "0" are backref
        if (c >= 48 && c < 64) { // 48 = "0", 64 = "@"
            this.offset += 1;
            return this.backrefQueue[c - 48];
        }
        // special exception: 0 doesn't use backref encoding
        // it's already one character, and it's always nullish
        if (c === 96) { // 96 = "`"
            this.offset += 1;
            return this.cons(0);
        }
        const result = this.cons(this.decode());
        this.backrefQueue.unshift(result);
        if (this.backrefQueue.length > 16) {
            this.backrefQueue.pop();
        }
        return result;
    }
}

/** @type {Array<string>} */
const EMPTY_STRING_ARRAY = [];

/** @type {Array<rustdoc.FunctionType>} */
const EMPTY_GENERICS_ARRAY = [];

/** @type {Array<[number, rustdoc.FunctionType[]]>} */
const EMPTY_BINDINGS_ARRAY = [];

/** @type {Map<number, Array<any>>} */
const EMPTY_BINDINGS_MAP = new Map();

/**
 * @param {string|null} typename
 * @returns {number}
 */
function itemTypeFromName(typename) {
    if (typename === null) {
        return NO_TYPE_FILTER;
    }
    const index = itemTypes.findIndex(i => i === typename);
    if (index < 0) {
        throw ["Unknown type filter ", typename];
    }
    return index;
}

class DocSearch {
    /**
     * @param {string} rootPath
     * @param {stringdex.Database} database
     */
    constructor(rootPath, database) {
        this.rootPath = rootPath;
        this.database = database;

        this.typeNameIdOfOutput = -1;
        this.typeNameIdOfArray = -1;
        this.typeNameIdOfSlice = -1;
        this.typeNameIdOfArrayOrSlice = -1;
        this.typeNameIdOfTuple = -1;
        this.typeNameIdOfUnit = -1;
        this.typeNameIdOfTupleOrUnit = -1;
        this.typeNameIdOfReference = -1;
        this.typeNameIdOfPointer = -1;
        this.typeNameIdOfHof = -1;

        this.utf8decoder = new TextDecoder();

        /** @type {Map<number|null, rustdoc.FunctionType>} */
        this.TYPES_POOL = new Map();
    }

    /**
     * Load search index. If you do not call this function, `execQuery`
     * will never fulfill.
     */
    async buildIndex() {
        const nn = this.database.getIndex("normalizedName");
        if (!nn) {
            return;
        }
        // Each of these identifiers are used specially by
        // type-driven search.
        const [
            // output is the special associated type that goes
            // after the arrow: the type checker desugars
            // the path `Fn(a) -> b` into `Fn<Output=b, (a)>`
            output,
            // fn, fnmut, and fnonce all match `->`
            fn,
            fnMut,
            fnOnce,
            hof,
            // array and slice both match `[]`
            array,
            slice,
            arrayOrSlice,
            // tuple and unit both match `()`
            tuple,
            unit,
            tupleOrUnit,
            // reference matches `&`
            reference,
            pointer,
            // never matches `!`
            never,
        ] = await Promise.all([
            nn.search("output"),
            nn.search("fn"),
            nn.search("fnmut"),
            nn.search("fnonce"),
            nn.search("->"),
            nn.search("array"),
            nn.search("slice"),
            nn.search("[]"),
            nn.search("tuple"),
            nn.search("unit"),
            nn.search("()"),
            nn.search("reference"),
            nn.search("pointer"),
            nn.search("never"),
        ]);
        /**
         * @param {stringdex.Trie|null|undefined} trie
         * @param {rustdoc.ItemType} ty
         * @param {string} modulePath
         * @returns {Promise<number>}
         * */
        const first = async(trie, ty, modulePath) => {
            if (trie) {
                for (const id of trie.matches().entries()) {
                    const pathData = await this.getPathData(id);
                    if (pathData && pathData.ty === ty && pathData.modulePath === modulePath) {
                        return id;
                    }
                }
            }
            return -1;
        };
        this.typeNameIdOfOutput = await first(output, TY_ASSOCTYPE, "");
        this.typeNameIdOfFnPtr = await first(fn, TY_PRIMITIVE, "");
        this.typeNameIdOfFn = await first(fn, TY_TRAIT, "core::ops");
        this.typeNameIdOfFnMut = await first(fnMut, TY_TRAIT, "core::ops");
        this.typeNameIdOfFnOnce = await first(fnOnce, TY_TRAIT, "core::ops");
        this.typeNameIdOfArray = await first(array, TY_PRIMITIVE, "");
        this.typeNameIdOfSlice = await first(slice, TY_PRIMITIVE, "");
        this.typeNameIdOfArrayOrSlice = await first(arrayOrSlice, TY_PRIMITIVE, "");
        this.typeNameIdOfTuple = await first(tuple, TY_PRIMITIVE, "");
        this.typeNameIdOfUnit = await first(unit, TY_PRIMITIVE, "");
        this.typeNameIdOfTupleOrUnit = await first(tupleOrUnit, TY_PRIMITIVE, "");
        this.typeNameIdOfReference = await first(reference, TY_PRIMITIVE, "");
        this.typeNameIdOfPointer = await first(pointer, TY_PRIMITIVE, "");
        this.typeNameIdOfHof = await first(hof, TY_PRIMITIVE, "");
        this.typeNameIdOfNever = await first(never, TY_PRIMITIVE, "");
    }

    /**
     * Parses the query.
     *
     * The supported syntax by this parser is given in the rustdoc book chapter
     * /src/doc/rustdoc/src/read-documentation/search.md
     *
     * When adding new things to the parser, add them there, too!
     *
     * @param  {string} userQuery - The user query
     *
     * @return {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} - The parsed query
     */
    static parseQuery(userQuery) {
        /**
         * Takes the user search input and returns an empty `ParsedQuery`.
         *
         * @param {string} userQuery
         *
         * @return {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>}
         */
        function newParsedQuery(userQuery) {
            return {
                userQuery,
                elems: [],
                returned: [],
                // Total number of "top" elements (does not include generics).
                foundElems: 0,
                // Total number of elements (includes generics).
                totalElems: 0,
                literalSearch: false,
                hasReturnArrow: false,
                error: null,
                correction: null,
                proposeCorrectionFrom: null,
                proposeCorrectionTo: null,
                // bloom filter build from type ids
                typeFingerprint: new Uint32Array(4),
            };
        }

        /**
        * Parses the provided `query` input to fill `parserState`. If it encounters an error while
        * parsing `query`, it'll throw an error.
        *
        * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
        * @param {rustdoc.ParserState} parserState
        */
        function parseInput(query, parserState) {
            let foundStopChar = true;

            while (parserState.pos < parserState.length) {
                const c = parserState.userQuery[parserState.pos];
                if (isEndCharacter(c)) {
                    foundStopChar = true;
                    if (isSeparatorCharacter(c)) {
                        parserState.pos += 1;
                        continue;
                    } else if (c === "-" || c === ">") {
                        if (isReturnArrow(parserState)) {
                            query.hasReturnArrow = true;
                            break;
                        }
                        throw ["Unexpected ", c, " (did you mean ", "->", "?)"];
                    } else if (parserState.pos > 0) {
                        throw ["Unexpected ", c, " after ",
                            parserState.userQuery[parserState.pos - 1]];
                    }
                    throw ["Unexpected ", c];
                } else if (c === " ") {
                    skipWhitespace(parserState);
                    continue;
                }
                if (!foundStopChar) {
                    let extra = EMPTY_STRING_ARRAY;
                    if (isLastElemGeneric(query.elems, parserState)) {
                        extra = [" after ", ">"];
                    } else if (prevIs(parserState, "\"")) {
                        throw ["Cannot have more than one element if you use quotes"];
                    }
                    if (parserState.typeFilter !== null) {
                        throw [
                            "Expected ",
                            ",",
                            " or ",
                            "->",
                            ...extra,
                            ", found ",
                            c,
                        ];
                    }
                    throw [
                        "Expected ",
                        ",",
                        ", ",
                        ":",
                        " or ",
                        "->",
                        ...extra,
                        ", found ",
                        c,
                    ];
                }
                const before = query.elems.length;
                getFilteredNextElem(query, parserState, query.elems, false);
                if (query.elems.length === before) {
                    // Nothing was added, weird... Let's increase the position to not remain stuck.
                    parserState.pos += 1;
                }
                foundStopChar = false;
            }
            if (parserState.typeFilter !== null) {
                throw [
                    "Unexpected ",
                    ":",
                    " (expected path after type filter ",
                    parserState.typeFilter + ":",
                    ")",
                ];
            }
            while (parserState.pos < parserState.length) {
                if (isReturnArrow(parserState)) {
                    parserState.pos += 2;
                    skipWhitespace(parserState);
                    // Get returned elements.
                    getItemsBefore(query, parserState, query.returned, "");
                    // Nothing can come afterward!
                    query.hasReturnArrow = true;
                    break;
                } else {
                    parserState.pos += 1;
                }
            }
        }


        userQuery = userQuery.trim().replace(/\r|\n|\t/g, " ");
        const parserState = {
            length: userQuery.length,
            pos: 0,
            // Total number of elements (includes generics).
            totalElems: 0,
            genericsElems: 0,
            typeFilter: null,
            isInBinding: null,
            userQuery,
        };
        let query = newParsedQuery(userQuery);

        try {
            parseInput(query, parserState);

            // Scan for invalid type filters, so that we can report the error
            // outside the search loop.
            /** @param {rustdoc.ParserQueryElement} elem */
            const checkTypeFilter = elem => {
                const ty = itemTypeFromName(elem.typeFilter);
                if (ty === TY_GENERIC && elem.generics.length !== 0) {
                    throw [
                        "Generic type parameter ",
                        elem.name,
                        " does not accept generic parameters",
                    ];
                }
                for (const generic of elem.generics) {
                    checkTypeFilter(generic);
                }
                for (const constraints of elem.bindings.values()) {
                    for (const constraint of constraints) {
                        checkTypeFilter(constraint);
                    }
                }
            };
            for (const elem of query.elems) {
                checkTypeFilter(elem);
            }
            for (const elem of query.returned) {
                checkTypeFilter(elem);
            }
        } catch (err) {
            query = newParsedQuery(userQuery);
            if (Array.isArray(err) && err.every(elem => typeof elem === "string")) {
                query.error = err;
            } else {
                // rethrow the error if it isn't a string array
                throw err;
            }

            return query;
        }
        if (!query.literalSearch) {
            // If there is more than one element in the query, we switch to literalSearch in any
            // case.
            query.literalSearch = parserState.totalElems > 1;
        }
        query.foundElems = query.elems.length + query.returned.length;
        query.totalElems = parserState.totalElems;
        return query;
    }

    /**
     * @param {number} id
     * @returns {Promise<string|null>}
     */
    async getName(id) {
        const ni = this.database.getData("name");
        if (!ni) {
            return null;
        }
        const name = await ni.at(id);
        return name === undefined || name === null ? null : this.utf8decoder.decode(name);
    }

    /**
     * @param {number} id
     * @returns {Promise<string|null>}
     */
    async getDesc(id) {
        const di = this.database.getData("desc");
        if (!di) {
            return null;
        }
        const desc = await di.at(id);
        return desc === undefined || desc === null ? null : this.utf8decoder.decode(desc);
    }

    /**
     * @param {number} id
     * @returns {Promise<number|null>}
     */
    async getAliasTarget(id) {
        const ai = this.database.getData("alias");
        if (!ai) {
            return null;
        }
        const bytes = await ai.at(id);
        if (bytes === undefined || bytes === null || bytes.length === 0) {
            return null;
        } else {
            /** @type {string} */
            const encoded = this.utf8decoder.decode(bytes);
            /** @type {number|null} */
            const decoded = JSON.parse(encoded);
            return decoded;
        }
    }

    /**
     * @param {number} id
     * @returns {Promise<rustdoc.EntryData|null>}
     */
    async getEntryData(id) {
        const ei = this.database.getData("entry");
        if (!ei) {
            return null;
        }
        const encoded = this.utf8decoder.decode(await ei.at(id));
        if (encoded === "" || encoded === undefined || encoded === null) {
            return null;
        }
        /**
         * krate,
         * ty,
         * module_path,
         * exact_module_path,
         * parent,
         * deprecated,
         * associated_item_disambiguator
         * @type {rustdoc.ArrayWithOptionals<[
         *     number,
         *     rustdoc.ItemType,
         *     number,
         *     number,
         *     number,
         *     number,
         * ], [string]>}
         */
        const raw = JSON.parse(encoded);
        return {
            krate: raw[0],
            ty: raw[1],
            modulePath: raw[2] === 0 ? null : raw[2] - 1,
            exactModulePath: raw[3] === 0 ? null : raw[3] - 1,
            parent: raw[4] === 0 ? null : raw[4] - 1,
            deprecated: raw[5] === 1 ? true : false,
            associatedItemDisambiguator: raw.length === 6 ? null : raw[6],
        };
    }

    /**
     * @param {number} id
     * @returns {Promise<rustdoc.PathData|null>}
     */
    async getPathData(id) {
        const pi = this.database.getData("path");
        if (!pi) {
            return null;
        }
        const encoded = this.utf8decoder.decode(await pi.at(id));
        if (encoded === "" || encoded === undefined || encoded === null) {
            return null;
        }
        /**
         * ty, module_path, exact_module_path, search_unbox, inverted_function_signature_index
         * @type {rustdoc.ArrayWithOptionals<[rustdoc.ItemType, string], [string|0, 0|1, string]>}
         */
        const raw = JSON.parse(encoded);
        return {
            ty: raw[0],
            modulePath: raw[1],
            exactModulePath: raw[2] === 0 || raw[2] === undefined ? raw[1] : raw[2],
        };
    }

    /**
     * @param {number} id
     * @returns {Promise<rustdoc.FunctionData|null>}
     */
    async getFunctionData(id) {
        const fi = this.database.getData("function");
        if (!fi) {
            return null;
        }
        const encoded = this.utf8decoder.decode(await fi.at(id));
        if (encoded === "" || encoded === undefined || encoded === null) {
            return null;
        }
        /**
         * function_signature, param_names
         * @type {[string, string[]]}
         */
        const raw = JSON.parse(encoded);

        const parser = new VlqHexDecoder(raw[0], async functionSearchType => {
            if (typeof functionSearchType === "number") {
                return null;
            }
            const INPUTS_DATA = 0;
            const OUTPUT_DATA = 1;
            /** @type {Promise<rustdoc.FunctionType[]>} */
            let inputs_;
            /** @type {Promise<rustdoc.FunctionType[]>} */
            let output_;
            if (typeof functionSearchType[INPUTS_DATA] === "number") {
                inputs_ = Promise.all([
                    this.buildItemSearchType(functionSearchType[INPUTS_DATA]),
                ]);
            } else {
                // @ts-ignore
                inputs_ = this.buildItemSearchTypeAll(functionSearchType[INPUTS_DATA]);
            }
            if (functionSearchType.length > 1) {
                if (typeof functionSearchType[OUTPUT_DATA] === "number") {
                    output_ = Promise.all([
                        this.buildItemSearchType(functionSearchType[OUTPUT_DATA]),
                    ]);
                } else {
                    // @ts-expect-error
                    output_ = this.buildItemSearchTypeAll(functionSearchType[OUTPUT_DATA]);
                }
            } else {
                output_ = Promise.resolve(EMPTY_GENERICS_ARRAY);
            }
            /** @type {Promise<rustdoc.FunctionType[]>[]} */
            const where_clause_ = [];
            const l = functionSearchType.length;
            for (let i = 2; i < l; ++i) {
                where_clause_.push(typeof functionSearchType[i] === "number"
                    // @ts-expect-error
                    ? Promise.all([this.buildItemSearchType(functionSearchType[i])])
                    // @ts-expect-error
                    : this.buildItemSearchTypeAll(functionSearchType[i]),
                );
            }
            const [inputs, output, where_clause] = await Promise.all([
                inputs_,
                output_,
                Promise.all(where_clause_),
            ]);
            return {
                inputs, output, where_clause,
            };
        });

        return {
            functionSignature: await parser.next(),
            paramNames: raw[1],
            elemCount: parser.elemCount,
        };
    }

    /**
     * @param {number} id
     * @returns {Promise<rustdoc.TypeData|null>}
     */
    async getTypeData(id) {
        const ti = this.database.getData("type");
        if (!ti) {
            return null;
        }
        const encoded = this.utf8decoder.decode(await ti.at(id));
        if (encoded === "" || encoded === undefined || encoded === null) {
            return null;
        }
        /**
         * function_signature, param_names
         * @type {[string, number] | [number] | [string] | [] | null}
         */
        const raw = JSON.parse(encoded);

        if (!raw || raw.length === 0) {
            return null;
        }

        let searchUnbox = false;
        const invertedFunctionSignatureIndex = [];

        if (typeof raw[0] === "string") {
            if (raw[1]) {
                searchUnbox = true;
            }
            // the inverted function signature index is a list of bitmaps,
            // by number of types that appear in the function
            let i = 0;
            const pb = makeUint8ArrayFromBase64(raw[0]);
            const l = pb.length;
            while (i < l) {
                if (pb[i] === 0) {
                    invertedFunctionSignatureIndex.push(RoaringBitmap.empty());
                    i += 1;
                } else {
                    const bitmap = new RoaringBitmap(pb, i);
                    i += bitmap.consumed_len_bytes;
                    invertedFunctionSignatureIndex.push(bitmap);
                }
            }
        } else if (raw[0]) {
            searchUnbox = true;
        }

        return { searchUnbox, invertedFunctionSignatureIndex };
    }

    /**
     * @returns {Promise<string[]>}
     */
    async getCrateNameList() {
        const crateNames = this.database.getData("crateNames");
        if (!crateNames) {
            return [];
        }
        const l = crateNames.length;
        const names = [];
        for (let i = 0; i < l; ++i) {
            names.push(crateNames.at(i).then(name => {
                if (name === undefined) {
                    return "";
                }
                return this.utf8decoder.decode(name);
            }));
        }
        return Promise.all(names);
    }

    /**
     * @param {number} id non-negative generic index
     * @returns {Promise<stringdex.RoaringBitmap[]>}
     */
    async getGenericInvertedIndex(id) {
        const gii = this.database.getData("generic_inverted_index");
        if (!gii) {
            return [];
        }
        const pb = await gii.at(id);
        if (pb === undefined || pb === null || pb.length === 0) {
            return [];
        }

        const invertedFunctionSignatureIndex = [];
        // the inverted function signature index is a list of bitmaps,
        // by number of types that appear in the function
        let i = 0;
        const l = pb.length;
        while (i < l) {
            if (pb[i] === 0) {
                invertedFunctionSignatureIndex.push(RoaringBitmap.empty());
                i += 1;
            } else {
                const bitmap = new RoaringBitmap(pb, i);
                i += bitmap.consumed_len_bytes;
                invertedFunctionSignatureIndex.push(bitmap);
            }
        }
        return invertedFunctionSignatureIndex;
    }

    /**
     * @param {number} id
     * @returns {Promise<rustdoc.Row?>}
     */
    async getRow(id) {
        const [name_, entry, path, type] = await Promise.all([
            this.getName(id),
            this.getEntryData(id),
            this.getPathData(id),
            this.getFunctionData(id),
        ]);
        if (!entry && !path) {
            return null;
        }
        const [
            moduleName,
            modulePathData,
            exactModuleName,
            exactModulePathData,
        ] = await Promise.all([
            entry && entry.modulePath !== null ? this.getName(entry.modulePath) : null,
            entry && entry.modulePath !== null ? this.getPathData(entry.modulePath) : null,
            entry && entry.exactModulePath !== null ?
                this.getName(entry.exactModulePath) :
                null,
            entry && entry.exactModulePath !== null ?
                this.getPathData(entry.exactModulePath) :
                null,
        ]);
        const name = name_ === null ? "" : name_;
        const normalizedName = (name.indexOf("_") === -1 ?
            name :
            name.replace(/_/g, "")).toLowerCase();
        const modulePath = modulePathData === null || moduleName === null ? "" :
            (modulePathData.modulePath === "" ?
                moduleName :
                `${modulePathData.modulePath}::${moduleName}`);
        const [parentName, parentPath] = entry !== null && entry.parent !== null ?
            await Promise.all([this.getName(entry.parent), this.getPathData(entry.parent)]) :
            [null, null];
        return {
            id,
            crate: entry ? nonnull(await this.getName(entry.krate)) : "",
            ty: entry ? entry.ty : nonnull(path).ty,
            name,
            normalizedName,
            modulePath,
            exactModulePath: exactModulePathData === null || exactModuleName === null ? modulePath :
                (exactModulePathData.exactModulePath === "" ?
                    exactModuleName :
                    `${exactModulePathData.exactModulePath}::${exactModuleName}`),
            entry,
            path,
            type,
            deprecated: entry ? entry.deprecated : false,
            parent: parentName !== null && parentPath !== null ?
                { name: parentName, path: parentPath } :
                null,
        };
    }

    /**
     * Convert a list of RawFunctionType / ID to object-based FunctionType.
     *
     * Crates often have lots of functions in them, and it's common to have a large number of
     * functions that operate on a small set of data types, so the search index compresses them
     * by encoding function parameter and return types as indexes into an array of names.
     *
     * Even when a general-purpose compression algorithm is used, this is still a win.
     * I checked. https://github.com/rust-lang/rust/pull/98475#issue-1284395985
     *
     * The format for individual function types is encoded in
     * librustdoc/html/render/mod.rs: impl Serialize for RenderType
     *
     * @param {null|Array<rustdoc.RawFunctionType>} types
     *
     * @return {Promise<Array<rustdoc.FunctionType>>}
     */
    async buildItemSearchTypeAll(types) {
        return types && types.length > 0 ?
            await Promise.all(types.map(type => this.buildItemSearchType(type))) :
            EMPTY_GENERICS_ARRAY;
    }

    /**
     * Converts a single type.
     *
     * @param {rustdoc.RawFunctionType} type
     * @return {Promise<rustdoc.FunctionType>}
     */
    async buildItemSearchType(type) {
        const PATH_INDEX_DATA = 0;
        const GENERICS_DATA = 1;
        const BINDINGS_DATA = 2;
        let id, generics;
        /**
         * @type {Map<number, rustdoc.FunctionType[]>}
         */
        let bindings;
        if (typeof type === "number") {
            id = type;
            generics = EMPTY_GENERICS_ARRAY;
            bindings = EMPTY_BINDINGS_MAP;
        } else {
            id = type[PATH_INDEX_DATA];
            generics = await this.buildItemSearchTypeAll(type[GENERICS_DATA]);
            if (type[BINDINGS_DATA] && type[BINDINGS_DATA].length > 0) {
                bindings = new Map((await Promise.all(type[BINDINGS_DATA].map(
                    /**
                     * @param {[rustdoc.RawFunctionType, rustdoc.RawFunctionType[]]} binding
                     * @returns {Promise<[number, rustdoc.FunctionType[]][]>}
                    */
                    async binding => {
                        const [assocType, constraints] = binding;
                        // Associated type constructors are represented sloppily in rustdoc's
                        // type search, to make the engine simpler.
                        //
                        // MyType<Output<T>=Result<T>> is equivalent to MyType<Output<Result<T>>=T>
                        // and both are, essentially
                        // MyType<Output=(T, Result<T>)>, except the tuple isn't actually there.
                        // It's more like the value of a type binding is naturally an array,
                        // which rustdoc calls "constraints".
                        //
                        // As a result, the key should never have generics on it.
                        const [k, v] = await Promise.all([
                            this.buildItemSearchType(assocType).then(t => t.id),
                            this.buildItemSearchTypeAll(constraints),
                        ]);
                        return k === null ? EMPTY_BINDINGS_ARRAY : [[k, v]];
                    },
                ))).flat());
            } else {
                bindings = EMPTY_BINDINGS_MAP;
            }
        }
        /**
         * @type {rustdoc.FunctionType}
         */
        let result;
        if (id < 0) {
            // types less than 0 are generic parameters
            // the actual names of generic parameters aren't stored, since they aren't API
            result = {
                id,
                name: "",
                ty: TY_GENERIC,
                path: null,
                exactPath: null,
                generics,
                bindings,
                unboxFlag: true,
            };
        } else if (id === 0) {
            // `0` is used as a sentinel because it's fewer bytes than `null`
            result = {
                id: null,
                name: "",
                ty: TY_GENERIC,
                path: null,
                exactPath: null,
                generics,
                bindings,
                unboxFlag: true,
            };
        } else {
            const [name, path, type] = await Promise.all([
                this.getName(id - 1),
                this.getPathData(id - 1),
                this.getTypeData(id - 1),
            ]);
            if (path === undefined || path === null || type === undefined || type === null) {
                return {
                    id: null,
                    name: "",
                    ty: TY_GENERIC,
                    path: null,
                    exactPath: null,
                    generics,
                    bindings,
                    unboxFlag: true,
                };
            }
            result = {
                id: id - 1,
                name,
                ty: path.ty,
                path: path.modulePath,
                exactPath: path.exactModulePath === null ? path.modulePath : path.exactModulePath,
                generics,
                bindings,
                unboxFlag: type.searchUnbox,
            };
        }
        const cr = this.TYPES_POOL.get(result.id);
        if (cr) {
            // Shallow equality check. Since this function is used
            // to construct every type object, this should be mostly
            // equivalent to a deep equality check, except if there's
            // a conflict, we don't keep the old one around, so it's
            // not a fully precise implementation of hashcons.
            if (cr.generics.length === result.generics.length &&
                cr.generics !== result.generics &&
                cr.generics.every((x, i) => result.generics[i] === x)
            ) {
                result.generics = cr.generics;
            }
            if (cr.bindings.size === result.bindings.size && cr.bindings !== result.bindings) {
                let ok = true;
                for (const [k, v] of cr.bindings.entries()) {
                    const v2 = result.bindings.get(k);
                    if (!v2) {
                        ok = false;
                        break;
                    }
                    if (v !== v2 && v.length === v2.length && v.every((x, i) => v2[i] === x)) {
                        result.bindings.set(k, v);
                    } else if (v !== v2) {
                        ok = false;
                        break;
                    }
                }
                if (ok) {
                    result.bindings = cr.bindings;
                }
            }
            if (cr.ty === result.ty && cr.path === result.path
                && cr.bindings === result.bindings && cr.generics === result.generics
                && cr.ty === result.ty && cr.name === result.name
                && cr.unboxFlag === result.unboxFlag
            ) {
                return cr;
            }
        }
        this.TYPES_POOL.set(result.id, result);
        return result;
    }

    /**
     * Executes the parsed query and builds a {ResultsTable}.
     *
     * @param  {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} parsedQuery
     *     - The parsed user query
     * @param  {Object} filterCrates - Crate to search in if defined
     * @param  {string} currentCrate - Current crate, to rank results from this crate higher
     *
     * @return {Promise<rustdoc.ResultsTable>}
     */
    async execQuery(parsedQuery, filterCrates, currentCrate) {
        const queryLen =
            parsedQuery.elems.reduce((acc, next) => acc + next.pathLast.length, 0) +
            parsedQuery.returned.reduce((acc, next) => acc + next.pathLast.length, 0);
        const maxEditDistance = Math.floor(queryLen / 3);

        /**
         * @param {rustdoc.Row} item
         * @returns {[string, string, string]}
         */
        const buildHrefAndPath = item => {
            let displayPath;
            let href;
            const type = itemTypes[item.ty];
            const name = item.name;
            let path = item.modulePath;
            let exactPath = item.exactModulePath;

            if (type === "mod") {
                displayPath = path + "::";
                href = this.rootPath + path.replace(/::/g, "/") + "/" +
                    name + "/index.html";
            } else if (type === "import") {
                displayPath = item.modulePath + "::";
                href = this.rootPath + item.modulePath.replace(/::/g, "/") +
                    "/index.html#reexport." + name;
            } else if (type === "primitive" || type === "keyword") {
                displayPath = "";
                exactPath = "";
                href = this.rootPath + path.replace(/::/g, "/") +
                    "/" + type + "." + name + ".html";
            } else if (type === "externcrate") {
                displayPath = "";
                href = this.rootPath + name + "/index.html";
            } else if (item.parent) {
                const myparent = item.parent;
                let anchor = type + "." + name;
                const parentType = itemTypes[myparent.path.ty];
                let pageType = parentType;
                let pageName = myparent.name;
                exactPath = `${myparent.path.exactModulePath}::${myparent.name}`;

                if (parentType === "primitive") {
                    displayPath = myparent.name + "::";
                    exactPath = myparent.name;
                } else if (type === "structfield" && parentType === "variant") {
                    // Structfields belonging to variants are special: the
                    // final path element is the enum name.
                    const enumNameIdx = item.modulePath.lastIndexOf("::");
                    const enumName = item.modulePath.substr(enumNameIdx + 2);
                    path = item.modulePath.substr(0, enumNameIdx);
                    displayPath = path + "::" + enumName + "::" + myparent.name + "::";
                    anchor = "variant." + myparent.name + ".field." + name;
                    pageType = "enum";
                    pageName = enumName;
                } else {
                    displayPath = path + "::" + myparent.name + "::";
                }
                if (item.entry && item.entry.associatedItemDisambiguator !== null) {
                    anchor = item.entry.associatedItemDisambiguator + "/" + anchor;
                }
                href = this.rootPath + path.replace(/::/g, "/") +
                    "/" + pageType +
                    "." + pageName +
                    ".html#" + anchor;
            } else {
                displayPath = item.modulePath + "::";
                href = this.rootPath + item.modulePath.replace(/::/g, "/") +
                    "/" + type + "." + name + ".html";
            }
            return [displayPath, href, `${exactPath}::${name}`];
        };

        /**
         *
         * @param {string} path
         * @returns {string}
         */
        function pathSplitter(path) {
            const tmp = "<span>" + path.replace(/::/g, "::</span><span>");
            if (tmp.endsWith("<span>")) {
                return tmp.slice(0, tmp.length - 6);
            }
            return tmp;
        }

        /**
         * Add extra data to result objects, and filter items that have been
         * marked for removal.
         *
         * The output is formatted as an array of hunks, where odd numbered
         * hunks are highlighted and even numbered ones are not.
         *
         * @param {rustdoc.ResultObject} obj
         * @param {"sig"|"elems"|"returned"|null} typeInfo
         * @param {rustdoc.QueryElement[]} elems
         * @param {rustdoc.QueryElement[]} returned
         * @returns {Promise<rustdoc.DisplayTypeSignature>}
         */
        const formatDisplayTypeSignature = async(obj, typeInfo, elems, returned) => {
            const objType = obj.type;
            if (!objType) {
                return {type: [], mappedNames: new Map(), whereClause: new Map()};
            }
            let fnInputs = null;
            let fnOutput = null;
            /** @type {Map<number, number> | null} */
            let mgens = null;
            if (typeInfo !== "elems" && typeInfo !== "returned") {
                fnInputs = unifyFunctionTypes(
                    objType.inputs,
                    elems,
                    objType.where_clause,
                    null,
                    mgensScratch => {
                        fnOutput = unifyFunctionTypes(
                            objType.output,
                            returned,
                            objType.where_clause,
                            mgensScratch,
                            mgensOut => {
                                mgens = mgensOut;
                                return true;
                            },
                            0,
                        );
                        return !!fnOutput;
                    },
                    0,
                );
            } else {
                const highlighted = unifyFunctionTypes(
                    typeInfo === "elems" ? objType.inputs : objType.output,
                    typeInfo === "elems" ? elems : returned,
                    objType.where_clause,
                    null,
                    mgensOut => {
                        mgens = mgensOut;
                        return true;
                    },
                    0,
                );
                if (typeInfo === "elems") {
                    fnInputs = highlighted;
                } else {
                    fnOutput = highlighted;
                }
            }
            if (!fnInputs) {
                fnInputs = objType.inputs;
            }
            if (!fnOutput) {
                fnOutput = objType.output;
            }
            const mappedNames = new Map();
            const whereClause = new Map();

            const fnParamNames = obj.paramNames || [];
            /** @type {string[]} */
            const queryParamNames = [];
            /**
             * Recursively writes a map of IDs to query generic names,
             * which are later used to map query generic names to function generic names.
             * For example, when the user writes `X -> Option<X>` and the function
             * is actually written as `T -> Option<T>`, this function stores the
             * mapping `(-1, "X")`, and the writeFn function looks up the entry
             * for -1 to form the final, user-visible mapping of "X is T".
             *
             * @param {rustdoc.QueryElement} queryElem
             */
            const remapQuery = queryElem => {
                if (queryElem.id !== null && queryElem.id < 0) {
                    queryParamNames[-1 - queryElem.id] = queryElem.name;
                }
                if (queryElem.generics.length > 0) {
                    queryElem.generics.forEach(remapQuery);
                }
                if (queryElem.bindings.size > 0) {
                    [...queryElem.bindings.values()].flat().forEach(remapQuery);
                }
            };

            elems.forEach(remapQuery);
            returned.forEach(remapQuery);

            /**
             * Write text to a highlighting array.
             * Index 0 is not highlighted, index 1 is highlighted,
             * index 2 is not highlighted, etc.
             *
             * @param {{name: string|null, highlighted?: boolean}} fnType - input
             * @param {string[]} result
             */
            const pushText = (fnType, result) => {
                // If !!(result.length % 2) == false, then pushing a new slot starts an even
                // numbered slot. Even numbered slots are not highlighted.
                //
                // `highlighted` will not be defined if an entire subtree is not highlighted,
                // so `!!` is used to coerce it to boolean. `result.length % 2` is used to
                // check if the number is even, but it evaluates to a number, so it also
                // needs coerced to a boolean.
                if (!!(result.length % 2) === !!fnType.highlighted) {
                    result.push("");
                } else if (result.length === 0 && !!fnType.highlighted) {
                    result.push("");
                    result.push("");
                }

                result[result.length - 1] += fnType.name;
            };

            /**
             * Write a higher order function type: either a function pointer
             * or a trait bound on Fn, FnMut, or FnOnce.
             *
             * @param {rustdoc.HighlightedFunctionType} fnType - input
             * @param {string[]} result
             * @returns {Promise<void>}
             */
            const writeHof = async(fnType, result) => {
                const hofOutput = fnType.bindings.get(this.typeNameIdOfOutput) || [];
                const hofInputs = fnType.generics;
                pushText(fnType, result);
                pushText({name: " (", highlighted: false}, result);
                let needsComma = false;
                for (const fnType of hofInputs) {
                    if (needsComma) {
                        pushText({ name: ", ", highlighted: false }, result);
                    }
                    needsComma = true;
                    await writeFn(fnType, result);
                }
                pushText({
                    name: hofOutput.length === 0 ? ")" : ") -> ",
                    highlighted: false,
                }, result);
                if (hofOutput.length > 1) {
                    pushText({name: "(", highlighted: false}, result);
                }
                needsComma = false;
                for (const fnType of hofOutput) {
                    if (needsComma) {
                        pushText({ name: ", ", highlighted: false }, result);
                    }
                    needsComma = true;
                    await writeFn(fnType, result);
                }
                if (hofOutput.length > 1) {
                    pushText({name: ")", highlighted: false}, result);
                }
            };

            /**
             * Write a primitive type with special syntax, like `!` or `[T]`.
             * Returns `false` if the supplied type isn't special.
             *
             * @param {rustdoc.HighlightedFunctionType} fnType
             * @param {string[]} result
             * @returns {Promise<boolean>}
             */
            const writeSpecialPrimitive = async(fnType, result) => {
                if (fnType.id === this.typeNameIdOfArray || fnType.id === this.typeNameIdOfSlice ||
                    fnType.id === this.typeNameIdOfTuple || fnType.id === this.typeNameIdOfUnit) {
                    const [ob, sb] =
                        fnType.id === this.typeNameIdOfArray ||
                            fnType.id === this.typeNameIdOfSlice ?
                        ["[", "]"] :
                        ["(", ")"];
                    pushText({ name: ob, highlighted: fnType.highlighted }, result);
                    await onEachBtwnAsync(
                        fnType.generics,
                        nested => writeFn(nested, result),
                        // @ts-expect-error
                        () => pushText({ name: ", ", highlighted: false }, result),
                    );
                    pushText({ name: sb, highlighted: fnType.highlighted }, result);
                    return true;
                } else if (fnType.id === this.typeNameIdOfReference) {
                    pushText({ name: "&", highlighted: fnType.highlighted }, result);
                    let prevHighlighted = false;
                    await onEachBtwnAsync(
                        fnType.generics,
                        async value => {
                            prevHighlighted = !!value.highlighted;
                            await writeFn(value, result);
                        },
                        // @ts-expect-error
                        value => pushText({
                            name: " ",
                            highlighted: prevHighlighted && value.highlighted,
                        }, result),
                    );
                    return true;
                } else if (fnType.id === this.typeNameIdOfPointer) {
                    pushText({ name: "*", highlighted: fnType.highlighted }, result);
                    if (fnType.generics.length < 2) {
                        pushText({ name: "const ", highlighted: fnType.highlighted }, result);
                    }
                    let prevHighlighted = false;
                    await onEachBtwnAsync(
                        fnType.generics,
                        async value => {
                            prevHighlighted = !!value.highlighted;
                            await writeFn(value, result);
                        },
                        // @ts-expect-error
                        value => pushText({
                            name: " ",
                            highlighted: prevHighlighted && value.highlighted,
                        }, result),
                    );
                    return true;
                } else if (
                    fnType.id === this.typeNameIdOfFn ||
                    fnType.id === this.typeNameIdOfFnMut ||
                    fnType.id === this.typeNameIdOfFnOnce ||
                    fnType.id === this.typeNameIdOfFnPtr
                ) {
                    await writeHof(fnType, result);
                    return true;
                } else if (fnType.id === this.typeNameIdOfNever) {
                    pushText({ name: "!", highlighted: fnType.highlighted }, result);
                    return true;
                }
                return false;
            };
            /**
             * Write a type. This function checks for special types,
             * like slices, with their own formatting. It also handles
             * updating the where clause and generic type param map.
             *
             * @param {rustdoc.HighlightedFunctionType} fnType
             * @param {string[]} result
             * @returns {Promise<void>}
             */
            const writeFn = async(fnType, result) => {
                if (fnType.id !== null && fnType.id < 0) {
                    if (fnParamNames[-1 - fnType.id] === "") {
                        // Normally, there's no need to shown an unhighlighted
                        // where clause, but if it's impl Trait, then we do.
                        const generics = fnType.generics.length > 0 ?
                            fnType.generics :
                            objType.where_clause[-1 - fnType.id];
                        for (const nested of generics) {
                            await writeFn(nested, result);
                        }
                        return;
                    } else if (mgens) {
                        for (const [queryId, fnId] of mgens) {
                            if (fnId === fnType.id) {
                                mappedNames.set(
                                    queryParamNames[-1 - queryId],
                                    fnParamNames[-1 - fnType.id],
                                );
                            }
                        }
                    }
                    pushText({
                        name: fnParamNames[-1 - fnType.id],
                        highlighted: !!fnType.highlighted,
                    }, result);
                    /** @type{string[]} */
                    const where = [];
                    await onEachBtwnAsync(
                        fnType.generics,
                        nested => writeFn(nested, where),
                        // @ts-expect-error
                        () => pushText({ name: " + ", highlighted: false }, where),
                    );
                    if (where.length > 0) {
                        whereClause.set(fnParamNames[-1 - fnType.id], where);
                    }
                } else {
                    if (fnType.ty === TY_PRIMITIVE) {
                        if (await writeSpecialPrimitive(fnType, result)) {
                            return;
                        }
                    } else if (fnType.ty === TY_TRAIT && (
                        fnType.id === this.typeNameIdOfFn ||
                        fnType.id === this.typeNameIdOfFnMut ||
                        fnType.id === this.typeNameIdOfFnOnce ||
                        fnType.id === this.typeNameIdOfFnPtr
                    )) {
                        await writeHof(fnType, result);
                        return;
                    } else if (fnType.name === "" &&
                        fnType.bindings.size === 0 &&
                        fnType.generics.length !== 0
                    ) {
                        pushText({ name: "impl ", highlighted: false }, result);
                        if (fnType.generics.length > 1) {
                            pushText({ name: "(", highlighted: false }, result);
                        }
                        await onEachBtwnAsync(
                            fnType.generics,
                            value => writeFn(value, result),
                            // @ts-expect-error
                            () => pushText({ name: ", ",  highlighted: false }, result),
                        );
                        if (fnType.generics.length > 1) {
                            pushText({ name: ")", highlighted: false }, result);
                        }
                        return;
                    }
                    pushText(fnType, result);
                    let hasBindings = false;
                    if (fnType.bindings.size > 0) {
                        await onEachBtwnAsync(
                            await Promise.all([...fnType.bindings.entries()].map(
                                /**
                                 * @param {[number, rustdoc.HighlightedFunctionType[]]} param0
                                 * @returns {Promise<[
                                 *     string|null,
                                 *     rustdoc.HighlightedFunctionType[],
                                 * ]>}
                                 */
                                async([key, values]) => [await this.getName(key), values],
                            )),
                            async([name, values]) => {
                                // @ts-expect-error
                                if (values.length === 1 && values[0].id < 0 &&
                                    // @ts-expect-error
                                    `${fnType.name}::${name}` === fnParamNames[-1 - values[0].id]
                                ) {
                                    // the internal `Item=Iterator::Item` type variable should be
                                    // shown in the where clause and name mapping output, but is
                                    // redundant in this spot
                                    for (const value of values) {
                                        await writeFn(value, []);
                                    }
                                    return true;
                                }
                                if (!hasBindings) {
                                    hasBindings = true;
                                    pushText({ name: "<", highlighted: false }, result);
                                }
                                pushText({ name, highlighted: false }, result);
                                pushText({
                                    name: values.length !== 1 ? "=(" : "=",
                                    highlighted: false,
                                }, result);
                                await onEachBtwnAsync(
                                    values || [],
                                    value => writeFn(value, result),
                                    // @ts-expect-error
                                    () => pushText({ name: " + ",  highlighted: false }, result),
                                );
                                if (values.length !== 1) {
                                    pushText({ name: ")", highlighted: false }, result);
                                }
                            },
                            // @ts-expect-error
                            () => pushText({ name: ", ",  highlighted: false }, result),
                        );
                    }
                    if (fnType.generics.length > 0) {
                        pushText({ name: hasBindings ? ", " : "<", highlighted: false }, result);
                    }
                    await onEachBtwnAsync(
                        fnType.generics,
                        value => writeFn(value, result),
                        // @ts-expect-error
                        () => pushText({ name: ", ",  highlighted: false }, result),
                    );
                    if (hasBindings || fnType.generics.length > 0) {
                        pushText({ name: ">", highlighted: false }, result);
                    }
                }
            };
            /** @type {string[]} */
            const type = [];
            await onEachBtwnAsync(
                fnInputs,
                fnType => writeFn(fnType, type),
                // @ts-expect-error
                () => pushText({ name: ", ",  highlighted: false }, type),
            );
            pushText({ name: " -> ", highlighted: false }, type);
            await onEachBtwnAsync(
                fnOutput,
                fnType => writeFn(fnType, type),
                // @ts-expect-error
                () => pushText({ name: ", ",  highlighted: false }, type),
            );

            return {type, mappedNames, whereClause};
        };

        /**
         * Add extra data to result objects, and filter items that have been
         * marked for removal.
         *
         * @param {[rustdoc.PlainResultObject, rustdoc.Row][]} results
         * @param {"sig"|"elems"|"returned"|null} typeInfo
         * @param {Set<string>} duplicates
         * @returns {rustdoc.ResultObject[]}
         */
        const transformResults = (results, typeInfo, duplicates) => {
            const out = [];

            for (const [result, item] of results) {
                if (item.id !== -1) {
                    const res = buildHrefAndPath(item);
                    // many of these properties don't strictly need to be
                    // copied over, but copying them over satisfies tsc,
                    // and hopefully plays nice with the shape optimization
                    // of the browser engine.
                    /** @type {rustdoc.ResultObject} */
                    const obj = Object.assign({
                        parent: item.parent ? {
                            path: item.parent.path.modulePath,
                            exactPath: item.parent.path.exactModulePath ||
                                item.parent.path.modulePath,
                            name: item.parent.name,
                            ty: item.parent.path.ty,
                        } : undefined,
                        type: item.type && item.type.functionSignature ?
                            item.type.functionSignature :
                            undefined,
                        paramNames: item.type && item.type.paramNames ?
                            item.type.paramNames :
                            undefined,
                        dist: result.dist,
                        path_dist: result.path_dist,
                        index: result.index,
                        desc: this.getDesc(result.id),
                        item,
                        displayPath: pathSplitter(res[0]),
                        fullPath: "",
                        href: "",
                        displayTypeSignature: null,
                    }, result);

                    // To be sure than it some items aren't considered as duplicate.
                    obj.fullPath = res[2] + "|" + obj.item.ty;

                    if (duplicates.has(obj.fullPath)) {
                        continue;
                    }

                    // Exports are specifically not shown if the items they point at
                    // are already in the results.
                    if (obj.item.ty === TY_IMPORT && duplicates.has(res[2])) {
                        continue;
                    }
                    if (duplicates.has(res[2] + "|" + TY_IMPORT)) {
                        continue;
                    }
                    duplicates.add(obj.fullPath);
                    duplicates.add(res[2]);

                    if (typeInfo !== null) {
                        obj.displayTypeSignature = formatDisplayTypeSignature(
                            obj,
                            typeInfo,
                            result.elems,
                            result.returned,
                        );
                    }

                    obj.href = res[1];
                    out.push(obj);
                    if (out.length >= MAX_RESULTS) {
                        break;
                    }
                }
            }

            return out;
        };

        const sortAndTransformResults =
            /**
             * @this {DocSearch}
             * @param {Array<rustdoc.PlainResultObject|null>} results
             * @param {"sig"|"elems"|"returned"|null} typeInfo
             * @param {string} preferredCrate
             * @param {Set<string>} duplicates
             * @returns {AsyncGenerator<rustdoc.ResultObject, number>}
             */
            async function*(results, typeInfo, preferredCrate, duplicates) {
                const userQuery = parsedQuery.userQuery;
                const normalizedUserQuery = parsedQuery.userQuery.toLowerCase();
                const isMixedCase = normalizedUserQuery !== userQuery;
                /**
                 * @type {[rustdoc.PlainResultObject, rustdoc.Row][]}
                 */
                const result_list = [];
                for (const result of results.values()) {
                    if (!result) {
                        continue;
                    }
                    /**
                     * @type {rustdoc.Row?}
                     */
                    const item = await this.getRow(result.id);
                    if (!item) {
                        continue;
                    }
                    if (filterCrates !== null && item.crate !== filterCrates) {
                        continue;
                    }
                    if (item) {
                        result_list.push([result, item]);
                    } else {
                        continue;
                    }
                }

                result_list.sort(([aaa, aai], [bbb, bbi]) => {
                    /** @type {number} */
                    let a;
                    /** @type {number} */
                    let b;

                    if (typeInfo === null) {
                        // in name based search...

                        // sort by exact case-sensitive match
                        if (isMixedCase) {
                            a = Number(aai.name !== userQuery);
                            b = Number(bbi.name !== userQuery);
                            if (a !== b) {
                                return a - b;
                            }
                        }

                        // sort by exact match with regard to the last word (mismatch goes later)
                        a = Number(aai.normalizedName !== normalizedUserQuery);
                        b = Number(bbi.normalizedName !== normalizedUserQuery);
                        if (a !== b) {
                            return a - b;
                        }

                        // sort by index of keyword in item name (no literal occurrence goes later)
                        a = Number(aaa.index < 0);
                        b = Number(bbb.index < 0);
                        if (a !== b) {
                            return a - b;
                        }
                    }

                    // Sort by distance in the path part, if specified
                    // (less changes required to match means higher rankings)
                    a = Number(aaa.path_dist);
                    b = Number(bbb.path_dist);
                    if (a !== b) {
                        return a - b;
                    }

                    // (later literal occurrence, if any, goes later)
                    a = Number(aaa.index);
                    b = Number(bbb.index);
                    if (a !== b) {
                        return a - b;
                    }

                    // Sort by distance in the name part, the last part of the path
                    // (less changes required to match means higher rankings)
                    a = Number(aaa.dist);
                    b = Number(bbb.dist);
                    if (a !== b) {
                        return a - b;
                    }

                    // sort aliases lower
                    a = Number(aaa.is_alias);
                    b = Number(bbb.is_alias);
                    if (a !== b) {
                        return a - b;
                    }

                    // sort deprecated items later
                    a = Number(aai.deprecated);
                    b = Number(bbi.deprecated);
                    if (a !== b) {
                        return a - b;
                    }

                    // sort by crate (current crate comes first)
                    a = Number(aai.crate !== preferredCrate);
                    b = Number(bbi.crate !== preferredCrate);
                    if (a !== b) {
                        return a - b;
                    }

                    // sort by item name length (longer goes later)
                    a = Number(aai.normalizedName.length);
                    b = Number(bbi.normalizedName.length);
                    if (a !== b) {
                        return a - b;
                    }

                    // sort by item name (lexicographically larger goes later)
                    let aw = aai.normalizedName;
                    let bw = bbi.normalizedName;
                    if (aw !== bw) {
                        return (aw > bw ? +1 : -1);
                    }

                    // sort by description (no description goes later)
                    const di = this.database.getData("desc");
                    if (di) {
                        a = Number(di.isEmpty(aaa.id));
                        b = Number(di.isEmpty(bbb.id));
                        if (a !== b) {
                            return a - b;
                        }
                    }

                    // sort by type (later occurrence in `itemTypes` goes later)
                    a = Number(aai.ty);
                    b = Number(bbi.ty);
                    if (a !== b) {
                        return a - b;
                    }

                    // sort by path (lexicographically larger goes later)
                    const ap = aai.modulePath;
                    const bp = bbi.modulePath;
                    aw = ap === undefined ? "" : ap;
                    bw = bp === undefined ? "" : bp;
                    if (aw !== bw) {
                        return (aw > bw ? +1 : -1);
                    }

                    // que sera, sera
                    return 0;
                });

                const transformed_result_list = transformResults(result_list, typeInfo, duplicates);
                yield* transformed_result_list;
                return transformed_result_list.length;
            }
            .bind(this);

        /**
         * This function checks if a list of search query `queryElems` can all be found in the
         * search index (`fnTypes`).
         *
         * This function returns highlighted results on a match, or `null`. If `solutionCb` is
         * supplied, it will call that function with mgens, and that callback can accept or
         * reject the result by returning `true` or `false`. If the callback returns false,
         * then this function will try with a different solution, or bail with null if it
         * runs out of candidates.
         *
         * @param {rustdoc.FunctionType[]} fnTypesIn - The objects to check.
         * @param {rustdoc.QueryElement[]} queryElems - The elements from the parsed query.
         * @param {rustdoc.FunctionType[][]} whereClause - Trait bounds for generic items.
         * @param {Map<number,number>|null} mgensIn
         *     - Map query generics to function generics (never modified).
         * @param {function(Map<number,number>?): boolean} solutionCb
         *     - Called for each `mgens` solution.
         * @param {number} unboxingDepth
         *     - Limit checks that Ty matches Vec<Ty>,
         *       but not Vec<ParamEnvAnd<WithInfcx<ConstTy<Interner<Ty=Ty>>>>>
         *
         * @return {rustdoc.HighlightedFunctionType[]|null}
         *     - Returns highlighted results if a match, null otherwise.
         */
        function unifyFunctionTypes(
            fnTypesIn,
            queryElems,
            whereClause,
            mgensIn,
            solutionCb,
            unboxingDepth,
        ) {
            if (unboxingDepth >= UNBOXING_LIMIT) {
                return null;
            }
            /**
             * @type {Map<number, number>|null}
             */
            const mgens = mgensIn === null ? null : new Map(mgensIn);
            if (queryElems.length === 0) {
                return solutionCb(mgens) ? fnTypesIn : null;
            }
            if (!fnTypesIn || fnTypesIn.length === 0) {
                return null;
            }
            const ql = queryElems.length;
            const fl = fnTypesIn.length;

            // One element fast path / base case
            if (ql === 1 && queryElems[0].generics.length === 0
                && queryElems[0].bindings.size === 0) {
                const queryElem = queryElems[0];
                for (const [i, fnType] of fnTypesIn.entries()) {
                    if (!unifyFunctionTypeIsMatchCandidate(fnType, queryElem, mgens)) {
                        continue;
                    }
                    if (fnType.id !== null &&
                        fnType.id < 0 &&
                        queryElem.id !== null &&
                        queryElem.id < 0
                    ) {
                        if (mgens && mgens.has(queryElem.id) &&
                            mgens.get(queryElem.id) !== fnType.id) {
                            continue;
                        }
                        const mgensScratch = new Map(mgens);
                        mgensScratch.set(queryElem.id, fnType.id);
                        if (!solutionCb || solutionCb(mgensScratch)) {
                            const highlighted = [...fnTypesIn];
                            highlighted[i] = Object.assign({
                                highlighted: true,
                            }, fnType, {
                                generics: whereClause[-1 - fnType.id],
                            });
                            return highlighted;
                        }
                    } else if (solutionCb(mgens ? new Map(mgens) : null)) {
                        // unifyFunctionTypeIsMatchCandidate already checks that ids match
                        const highlighted = [...fnTypesIn];
                        highlighted[i] = Object.assign({
                            highlighted: true,
                        }, fnType, {
                            generics: unifyGenericTypes(
                                fnType.generics,
                                queryElem.generics,
                                whereClause,
                                mgens ? new Map(mgens) : null,
                                solutionCb,
                                unboxingDepth,
                            ) || fnType.generics,
                        });
                        return highlighted;
                    }
                }
                for (const [i, fnType] of fnTypesIn.entries()) {
                    if (!unifyFunctionTypeIsUnboxCandidate(
                        fnType,
                        queryElem,
                        whereClause,
                        mgens,
                        unboxingDepth + 1,
                    )) {
                        continue;
                    }
                    // @ts-expect-error
                    if (fnType.id < 0) {
                        const highlightedGenerics = unifyFunctionTypes(
                            // @ts-expect-error
                            whereClause[(-fnType.id) - 1],
                            queryElems,
                            whereClause,
                            mgens,
                            solutionCb,
                            unboxingDepth + 1,
                        );
                        if (highlightedGenerics) {
                            const highlighted = [...fnTypesIn];
                            highlighted[i] = Object.assign({
                                highlighted: true,
                            }, fnType, {
                                generics: highlightedGenerics,
                            });
                            return highlighted;
                        }
                    } else {
                        const highlightedGenerics = unifyFunctionTypes(
                            [...Array.from(fnType.bindings.values()).flat(), ...fnType.generics],
                            queryElems,
                            whereClause,
                            mgens ? new Map(mgens) : null,
                            solutionCb,
                            unboxingDepth + 1,
                        );
                        if (highlightedGenerics) {
                            const highlighted = [...fnTypesIn];
                            highlighted[i] = Object.assign({}, fnType, {
                                generics: highlightedGenerics,
                                bindings: new Map([...fnType.bindings.entries()].map(([k, v]) => {
                                    return [k, highlightedGenerics.splice(0, v.length)];
                                })),
                            });
                            return highlighted;
                        }
                    }
                }
                return null;
            }

            // Multiple element recursive case
            /**
             * @type {Array<rustdoc.FunctionType>}
             */
            const fnTypes = fnTypesIn.slice();
            /**
             * Algorithm works by building up a solution set in the working arrays
             * fnTypes gets mutated in place to make this work, while queryElems
             * is left alone.
             *
             * It works backwards, because arrays can be cheaply truncated that way.
             *
             *                         vvvvvvv `queryElem`
             * queryElems = [ unknown, unknown, good, good, good ]
             * fnTypes    = [ unknown, unknown, good, good, good ]
             *                ^^^^^^^^^^^^^^^^ loop over these elements to find candidates
             *
             * Everything in the current working solution is known to be a good
             * match, but it might not be the match we wind up going with, because
             * there might be more than one candidate match, and we need to try them all
             * before giving up. So, to handle this, it backtracks on failure.
             */
            const flast = fl - 1;
            const qlast = ql - 1;
            const queryElem = queryElems[qlast];
            let queryElemsTmp = null;
            for (let i = flast; i >= 0; i -= 1) {
                const fnType = fnTypes[i];
                if (!unifyFunctionTypeIsMatchCandidate(fnType, queryElem, mgens)) {
                    continue;
                }
                let mgensScratch;
                if (fnType.id !== null && queryElem.id !== null && fnType.id < 0) {
                    mgensScratch = new Map(mgens);
                    if (mgensScratch.has(queryElem.id)
                        && mgensScratch.get(queryElem.id) !== fnType.id) {
                        continue;
                    }
                    mgensScratch.set(queryElem.id, fnType.id);
                } else {
                    mgensScratch = mgens;
                }
                // fnTypes[i] is a potential match
                // fnTypes[flast] is the last item in the list
                // swap them, and drop the potential match from the list
                // check if the remaining function types also match
                fnTypes[i] = fnTypes[flast];
                fnTypes.length = flast;
                if (!queryElemsTmp) {
                    queryElemsTmp = queryElems.slice(0, qlast);
                }
                /** @type {rustdoc.HighlightedFunctionType[]|null} */
                let unifiedGenerics = [];
                /** @type {null|Map<number, number>} */
                let unifiedGenericsMgens = null;
                /** @type {rustdoc.HighlightedFunctionType[]|null} */
                const passesUnification = unifyFunctionTypes(
                    fnTypes,
                    queryElemsTmp,
                    whereClause,
                    mgensScratch,
                    mgensScratch => {
                        if (fnType.generics.length === 0 && queryElem.generics.length === 0
                            && fnType.bindings.size === 0 && queryElem.bindings.size === 0) {
                            return solutionCb(mgensScratch);
                        }
                        const solution = unifyFunctionTypeCheckBindings(
                            fnType,
                            queryElem,
                            whereClause,
                            mgensScratch,
                            unboxingDepth,
                        );
                        if (!solution) {
                            return false;
                        }
                        const simplifiedGenerics = solution.simplifiedGenerics;
                        for (const simplifiedMgens of solution.mgens) {
                            unifiedGenerics = unifyGenericTypes(
                                simplifiedGenerics,
                                queryElem.generics,
                                whereClause,
                                simplifiedMgens,
                                solutionCb,
                                unboxingDepth,
                            );
                            if (unifiedGenerics !== null) {
                                unifiedGenericsMgens = simplifiedMgens;
                                return true;
                            }
                        }
                        return false;
                    },
                    unboxingDepth,
                );
                if (passesUnification) {
                    passesUnification.length = fl;
                    passesUnification[flast] = passesUnification[i];
                    passesUnification[i] = Object.assign({}, fnType, {
                        highlighted: true,
                        generics: unifiedGenerics,
                        bindings: new Map([...fnType.bindings.entries()].map(([k, v]) => {
                            return [k, queryElem.bindings.has(k) ? unifyFunctionTypes(
                                v,
                                // @ts-expect-error
                                queryElem.bindings.get(k),
                                whereClause,
                                unifiedGenericsMgens,
                                solutionCb,
                                unboxingDepth,
                            // @ts-expect-error
                            ) : unifiedGenerics.splice(0, v.length)];
                        })),
                    });
                    return passesUnification;
                }
                // backtrack
                fnTypes[flast] = fnTypes[i];
                fnTypes[i] = fnType;
                fnTypes.length = fl;
            }
            for (let i = flast; i >= 0; i -= 1) {
                const fnType = fnTypes[i];
                if (!unifyFunctionTypeIsUnboxCandidate(
                    fnType,
                    queryElem,
                    whereClause,
                    mgens,
                    unboxingDepth + 1,
                )) {
                    continue;
                }
                const generics = fnType.id !== null && fnType.id < 0 ?
                    whereClause[(-fnType.id) - 1] :
                    fnType.generics;
                const bindings = fnType.bindings ?
                    Array.from(fnType.bindings.values()).flat() :
                    [];
                const passesUnification = unifyFunctionTypes(
                    fnTypes.toSpliced(i, 1, ...bindings, ...generics),
                    queryElems,
                    whereClause,
                    mgens,
                    solutionCb,
                    unboxingDepth + 1,
                );
                if (passesUnification) {
                    const highlightedGenerics = passesUnification.slice(
                        i,
                        i + generics.length + bindings.length,
                    );
                    const highlightedFnType = Object.assign({}, fnType, {
                        generics: highlightedGenerics,
                        bindings: new Map([...fnType.bindings.entries()].map(([k, v]) => {
                            return [k, highlightedGenerics.splice(0, v.length)];
                        })),
                    });
                    return passesUnification.toSpliced(
                        i,
                        generics.length + bindings.length,
                        highlightedFnType,
                    );
                }
            }
            return null;
        }
        /**
         * This function compares two lists of generics.
         *
         * This function behaves very similarly to `unifyFunctionTypes`, except that it
         * doesn't skip or reorder anything. This is intended to match the behavior of
         * the ordinary Rust type system, so that `Vec<Allocator>` only matches an actual
         * `Vec` of `Allocators` and not the implicit `Allocator` parameter that every
         * `Vec` has.
         *
         * @param {Array<rustdoc.FunctionType>} fnTypesIn - The objects to check.
         * @param {Array<rustdoc.QueryElement>} queryElems - The elements from the parsed query.
         * @param {rustdoc.FunctionType[][]} whereClause - Trait bounds for generic items.
         * @param {Map<number,number>|null} mgensIn
         *     - Map functions generics to query generics (never modified).
         * @param {function(Map<number,number>): boolean} solutionCb
         *     - Called for each `mgens` solution.
         * @param {number} unboxingDepth
         *     - Limit checks that Ty matches Vec<Ty>,
         *       but not Vec<ParamEnvAnd<WithInfcx<ConstTy<Interner<Ty=Ty>>>>>
         *
         * @return {rustdoc.HighlightedFunctionType[]|null}
         *     - Returns highlighted results if a match, null otherwise.
         */
        function unifyGenericTypes(
            fnTypesIn,
            queryElems,
            whereClause,
            mgensIn,
            solutionCb,
            unboxingDepth,
        ) {
            if (unboxingDepth >= UNBOXING_LIMIT) {
                return null;
            }
            /**
             * @type {Map<number, number>|null}
             */
            const mgens = mgensIn === null ? null : new Map(mgensIn);
            if (queryElems.length === 0) {
                // @ts-expect-error
                return solutionCb(mgens) ? fnTypesIn : null;
            }
            if (!fnTypesIn || fnTypesIn.length === 0) {
                return null;
            }
            const fnType = fnTypesIn[0];
            const queryElem = queryElems[0];
            if (unifyFunctionTypeIsMatchCandidate(fnType, queryElem, mgens)) {
                if (fnType.id !== null &&
                    fnType.id < 0 &&
                    queryElem.id !== null &&
                    queryElem.id < 0
                ) {
                    if (!mgens || !mgens.has(queryElem.id) ||
                        mgens.get(queryElem.id) === fnType.id
                    ) {
                        const mgensScratch = new Map(mgens);
                        mgensScratch.set(queryElem.id, fnType.id);
                        const fnTypesRemaining = unifyGenericTypes(
                            fnTypesIn.slice(1),
                            queryElems.slice(1),
                            whereClause,
                            mgensScratch,
                            solutionCb,
                            unboxingDepth,
                        );
                        if (fnTypesRemaining) {
                            const highlighted = [fnType, ...fnTypesRemaining];
                            highlighted[0] = Object.assign({
                                highlighted: true,
                            }, fnType, {
                                generics: whereClause[-1 - fnType.id],
                            });
                            return highlighted;
                        }
                    }
                } else {
                    let unifiedGenerics;
                    const fnTypesRemaining = unifyGenericTypes(
                        fnTypesIn.slice(1),
                        queryElems.slice(1),
                        whereClause,
                        mgens,
                        // @ts-expect-error
                        mgensScratch => {
                            const solution = unifyFunctionTypeCheckBindings(
                                fnType,
                                queryElem,
                                whereClause,
                                mgensScratch,
                                unboxingDepth,
                            );
                            if (!solution) {
                                return false;
                            }
                            const simplifiedGenerics = solution.simplifiedGenerics;
                            for (const simplifiedMgens of solution.mgens) {
                                unifiedGenerics = unifyGenericTypes(
                                    simplifiedGenerics,
                                    queryElem.generics,
                                    whereClause,
                                    simplifiedMgens,
                                    solutionCb,
                                    unboxingDepth,
                                );
                                if (unifiedGenerics !== null) {
                                    return true;
                                }
                            }
                        },
                        unboxingDepth,
                    );
                    if (fnTypesRemaining) {
                        const highlighted = [fnType, ...fnTypesRemaining];
                        highlighted[0] = Object.assign({
                            highlighted: true,
                        }, fnType, {
                            generics: unifiedGenerics || fnType.generics,
                        });
                        return highlighted;
                    }
                }
            }
            if (unifyFunctionTypeIsUnboxCandidate(
                fnType,
                queryElem,
                whereClause,
                mgens,
                unboxingDepth + 1,
            )) {
                let highlightedRemaining;
                if (fnType.id !== null && fnType.id < 0) {
                    // Where clause corresponds to `F: A + B`
                    //                                 ^^^^^
                    // The order of the constraints doesn't matter, so
                    // use order-agnostic matching for it.
                    const highlightedGenerics = unifyFunctionTypes(
                        whereClause[(-fnType.id) - 1],
                        [queryElem],
                        whereClause,
                        mgens,
                        // @ts-expect-error
                        mgensScratch => {
                            const hl = unifyGenericTypes(
                                fnTypesIn.slice(1),
                                queryElems.slice(1),
                                whereClause,
                                mgensScratch,
                                solutionCb,
                                unboxingDepth,
                            );
                            if (hl) {
                                highlightedRemaining = hl;
                            }
                            return hl;
                        },
                        unboxingDepth + 1,
                    );
                    if (highlightedGenerics) {
                        return [Object.assign({
                            highlighted: true,
                        }, fnType, {
                            generics: highlightedGenerics,
                        // @ts-expect-error
                        }), ...highlightedRemaining];
                    }
                } else {
                    const highlightedGenerics = unifyGenericTypes(
                        [
                            ...Array.from(fnType.bindings.values()).flat(),
                            ...fnType.generics,
                        ],
                        [queryElem],
                        whereClause,
                        mgens,
                        // @ts-expect-error
                        mgensScratch => {
                            const hl = unifyGenericTypes(
                                fnTypesIn.slice(1),
                                queryElems.slice(1),
                                whereClause,
                                mgensScratch,
                                solutionCb,
                                unboxingDepth,
                            );
                            if (hl) {
                                highlightedRemaining = hl;
                            }
                            return hl;
                        },
                        unboxingDepth + 1,
                    );
                    if (highlightedGenerics) {
                        return [Object.assign({}, fnType, {
                            generics: highlightedGenerics,
                            bindings: new Map([...fnType.bindings.entries()].map(([k, v]) => {
                                return [k, highlightedGenerics.splice(0, v.length)];
                            })),
                        // @ts-expect-error
                        }), ...highlightedRemaining];
                    }
                }
            }
            return null;
        }
        /**
         * Check if this function is a match candidate.
         *
         * This function is all the fast checks that don't require backtracking.
         * It checks that two items are not named differently, and is load-bearing for that.
         * It also checks that, if the query has generics, the function type must have generics
         * or associated type bindings: that's not load-bearing, but it prevents unnecessary
         * backtracking later.
         *
         * @param {rustdoc.FunctionType} fnType
         * @param {rustdoc.QueryElement} queryElem
         * @param {Map<number,number>|null} mgensIn - Map query generics to function generics.
         * @returns {boolean}
         */
        const unifyFunctionTypeIsMatchCandidate = (fnType, queryElem, mgensIn) => {
            // type filters look like `trait:Read` or `enum:Result`
            if (!typePassesFilter(queryElem.typeFilter, fnType.ty)) {
                return false;
            }
            // fnType.id < 0 means generic
            // queryElem.id < 0 does too
            // mgensIn[queryElem.id] = fnType.id
            if (fnType.id !== null && fnType.id < 0 && queryElem.id !== null && queryElem.id < 0) {
                if (
                    mgensIn && mgensIn.has(queryElem.id) &&
                    mgensIn.get(queryElem.id) !== fnType.id
                ) {
                    return false;
                }
                return true;
            } else {
                // For these special cases, matching code need added to the inverted index.
                // search_index.rs -> convert_render_type does this
                if (queryElem.id === this.typeNameIdOfArrayOrSlice &&
                    (fnType.id === this.typeNameIdOfSlice || fnType.id === this.typeNameIdOfArray)
                ) {
                    // [] matches primitive:array or primitive:slice
                    // if it matches, then we're fine, and this is an appropriate match candidate
                } else if (queryElem.id === this.typeNameIdOfTupleOrUnit &&
                    (fnType.id === this.typeNameIdOfTuple || fnType.id === this.typeNameIdOfUnit)
                ) {
                    // () matches primitive:tuple or primitive:unit
                    // if it matches, then we're fine, and this is an appropriate match candidate
                } else if (queryElem.id === this.typeNameIdOfHof && (
                    fnType.id === this.typeNameIdOfFn ||
                    fnType.id === this.typeNameIdOfFnMut ||
                    fnType.id === this.typeNameIdOfFnOnce ||
                    fnType.id === this.typeNameIdOfFnPtr
                )) {
                    // -> matches fn, fnonce, and fnmut
                    // if it matches, then we're fine, and this is an appropriate match candidate
                } else if (fnType.id !== queryElem.id || queryElem.id === null) {
                    return false;
                }
                // If the query elem has generics, and the function doesn't,
                // it can't match.
                if ((fnType.generics.length + fnType.bindings.size) === 0 &&
                    queryElem.generics.length !== 0
                ) {
                    return false;
                }
                if (fnType.bindings.size < queryElem.bindings.size) {
                    return false;
                }
                // If the query element is a path (it contains `::`), we need to check if this
                // path is compatible with the target type.
                const queryElemPathLength = queryElem.pathWithoutLast.length;
                if (queryElemPathLength > 0) {
                    const fnTypePath = fnType.path !== undefined && fnType.path !== null ?
                        fnType.path.split("::") : [];
                    // If the path provided in the query element is longer than this type,
                    // no need to check it since it won't match in any case.
                    if (queryElemPathLength > fnTypePath.length) {
                        return false;
                    }
                    let i = 0;
                    for (const path of fnTypePath) {
                        if (path === queryElem.pathWithoutLast[i]) {
                            i += 1;
                            if (i >= queryElemPathLength) {
                                break;
                            }
                        }
                    }
                    if (i < queryElemPathLength) {
                        // If we didn't find all parts of the path of the query element inside
                        // the fn type, then it's not the right one.
                        return false;
                    }
                }
                return true;
            }
        };
        /**
         * This function checks the associated type bindings. Any that aren't matched get converted
         * to generics, and this function returns an array of the function's generics with these
         * simplified bindings added to them. That is, it takes a path like this:
         *
         *     Iterator<Item=u32>
         *
         * ... if queryElem itself has an `Item=` in it, then this function returns an empty array.
         * But if queryElem contains no Item=, then this function returns a one-item array with the
         * ID of u32 in it, and the rest of the matching engine acts as if `Iterator<u32>` were
         * the type instead.
         *
         * @param {rustdoc.FunctionType} fnType
         * @param {rustdoc.QueryElement} queryElem
         * @param {rustdoc.FunctionType[][]} whereClause - Trait bounds for generic items.
         * @param {Map<number,number>|null} mgensIn - Map query generics to function generics.
         *                                            Never modified.
         * @param {number} unboxingDepth
         * @returns {false|{
         *     mgens: [Map<number,number>|null], simplifiedGenerics: rustdoc.FunctionType[]
         * }}
         */
        function unifyFunctionTypeCheckBindings(
            fnType,
            queryElem,
            whereClause,
            mgensIn,
            unboxingDepth,
        ) {
            if (fnType.bindings.size < queryElem.bindings.size) {
                return false;
            }
            let simplifiedGenerics = fnType.generics || [];
            if (fnType.bindings.size > 0) {
                let mgensSolutionSet = [mgensIn];
                for (const [name, constraints] of queryElem.bindings.entries()) {
                    if (mgensSolutionSet.length === 0) {
                        return false;
                    }
                    if (!fnType.bindings.has(name)) {
                        return false;
                    }
                    const fnTypeBindings = fnType.bindings.get(name);
                    mgensSolutionSet = mgensSolutionSet.flatMap(mgens => {
                        /** @type{Array<Map<number, number> | null>} */
                        const newSolutions = [];
                        unifyFunctionTypes(
                            // @ts-expect-error
                            fnTypeBindings,
                            constraints,
                            whereClause,
                            mgens,
                            newMgens => {
                                newSolutions.push(newMgens);
                                // return `false` makes unifyFunctionTypes return the full set of
                                // possible solutions
                                return false;
                            },
                            unboxingDepth,
                        );
                        return newSolutions;
                    });
                }
                if (mgensSolutionSet.length === 0) {
                    return false;
                }
                const binds = Array.from(fnType.bindings.entries()).flatMap(entry => {
                    const [name, constraints] = entry;
                    if (queryElem.bindings.has(name)) {
                        return [];
                    } else {
                        return constraints;
                    }
                });
                if (simplifiedGenerics.length > 0) {
                    simplifiedGenerics = [...binds, ...simplifiedGenerics];
                } else {
                    simplifiedGenerics = binds;
                }
                // @ts-expect-error
                return { simplifiedGenerics, mgens: mgensSolutionSet };
            }
            return { simplifiedGenerics, mgens: [mgensIn] };
        }
        /**
         * @param {rustdoc.FunctionType} fnType
         * @param {rustdoc.QueryElement} queryElem
         * @param {rustdoc.FunctionType[][]} whereClause - Trait bounds for generic items.
         * @param {Map<number,number>|null} mgens - Map query generics to function generics.
         * @param {number} unboxingDepth
         * @returns {boolean}
         */
        function unifyFunctionTypeIsUnboxCandidate(
            fnType,
            queryElem,
            whereClause,
            mgens,
            unboxingDepth,
        ) {
            if (unboxingDepth >= UNBOXING_LIMIT) {
                return false;
            }
            if (fnType.id !== null && fnType.id < 0) {
                if (!whereClause) {
                    return false;
                }
                // This is only a potential unbox if the search query appears in the where clause
                // for example, searching `Read -> usize` should find
                // `fn read_all<R: Read>(R) -> Result<usize>`
                // generic `R` is considered "unboxed"
                return checkIfInList(
                    whereClause[(-fnType.id) - 1],
                    queryElem,
                    whereClause,
                    mgens,
                    unboxingDepth,
                );
            } else if (fnType.unboxFlag &&
                (fnType.generics.length > 0 || fnType.bindings.size > 0)) {
                const simplifiedGenerics = [
                    ...fnType.generics,
                    ...Array.from(fnType.bindings.values()).flat(),
                ];
                return checkIfInList(
                    simplifiedGenerics,
                    queryElem,
                    whereClause,
                    mgens,
                    unboxingDepth,
                );
            }
            return false;
        }

        /**
         * This function checks if the given list contains any
         * (non-generic) types mentioned in the query.
         *
         * @param {rustdoc.QueryElement[]} elems
         * @param {rustdoc.FunctionType[]} list    - A list of function types.
         * @param {rustdoc.FunctionType[][]} where_clause - Trait bounds for generic items.
         */
        function containsTypeFromQuery(elems, list, where_clause) {
            if (!list) return false;
            for (const ty of elems) {
                if (ty.id !== null && ty.id < 0) {
                    continue;
                }
                if (checkIfInList(list, ty, where_clause, null, 0)) {
                    return true;
                }
            }
            return false;
        }

        /**
         * This function checks if the object (`row`) matches the given type (`elem`) and its
         * generics (if any).
         *
         * @param {rustdoc.FunctionType[]} list
         * @param {rustdoc.QueryElement} elem          - The element from the parsed query.
         * @param {rustdoc.FunctionType[][]} whereClause - Trait bounds for generic items.
         * @param {Map<number,number>|null} mgens - Map functions generics to query generics.
         * @param {number} unboxingDepth
         *
         * @return {boolean} - Returns true if found, false otherwise.
         */
        function checkIfInList(list, elem, whereClause, mgens, unboxingDepth) {
            for (const entry of list) {
                if (checkType(entry, elem, whereClause, mgens, unboxingDepth)) {
                    return true;
                }
            }
            return false;
        }

        /**
         * This function checks if the object (`row`) matches the given type (`elem`) and its
         * generics (if any).
         *
         * @param {rustdoc.FunctionType} row
         * @param {rustdoc.QueryElement} elem          - The element from the parsed query.
         * @param {rustdoc.FunctionType[][]} whereClause - Trait bounds for generic items.
         * @param {Map<number,number>|null} mgens - Map query generics to function generics.
         *
         * @return {boolean} - Returns true if the type matches, false otherwise.
         */
        // @ts-expect-error
        const checkType = (row, elem, whereClause, mgens, unboxingDepth) => {
            if (unboxingDepth >= UNBOXING_LIMIT) {
                return false;
            }
            if (row.id !== null && elem.id !== null &&
                row.id > 0 && elem.id > 0 && elem.pathWithoutLast.length === 0 &&
                row.generics.length === 0 && elem.generics.length === 0 &&
                row.bindings.size === 0 && elem.bindings.size === 0 &&
                // special case
                elem.id !== this.typeNameIdOfArrayOrSlice &&
                elem.id !== this.typeNameIdOfHof &&
                elem.id !== this.typeNameIdOfTupleOrUnit
            ) {
                return row.id === elem.id && typePassesFilter(elem.typeFilter, row.ty);
            } else {
                // @ts-expect-error
                return unifyFunctionTypes(
                    [row],
                    [elem],
                    whereClause,
                    mgens,
                    () => true,
                    unboxingDepth,
                );
            }
        };

        /**
         * Check a query solution for conflicting generics.
         */
        // @ts-expect-error
        const checkTypeMgensForConflict = mgens => {
            if (!mgens) {
                return true;
            }
            const fnTypes = new Set();
            for (const [_qid, fid] of mgens) {
                if (fnTypes.has(fid)) {
                    return false;
                }
                fnTypes.add(fid);
            }
            return true;
        };

        /**
         * Compute an "edit distance" that ignores missing path elements.
         * @param {string[]} contains search query path
         * @param {string[]} path indexed page path
         * @returns {null|number} edit distance
         */
        function checkPath(contains, path) {
            if (contains.length === 0) {
                return 0;
            }
            const maxPathEditDistance = Math.floor(
                contains.reduce((acc, next) => acc + next.length, 0) / 3,
            );
            let ret_dist = maxPathEditDistance + 1;

            const length = path.length;
            const clength = contains.length;
            pathiter: for (let i = length - clength; i >= 0; i -= 1) {
                let dist_total = 0;
                for (let x = 0; x < clength; ++x) {
                    const [p, c] = [path[i + x], contains[x]];
                    if (Math.floor((p.length - c.length) / 3) <= maxPathEditDistance &&
                        p.indexOf(c) !== -1
                    ) {
                        // discount distance on substring match
                        dist_total += Math.floor((p.length - c.length) / 3);
                    } else {
                        const dist = editDistance(p, c, maxPathEditDistance);
                        if (dist > maxPathEditDistance) {
                            continue pathiter;
                        }
                        dist_total += dist;
                    }
                }
                ret_dist = Math.min(ret_dist, Math.round(dist_total / clength));
            }
            return ret_dist > maxPathEditDistance ? null : ret_dist;
        }

        /**
         * Compute an "edit distance" that ignores missing path elements.
         * @param {string[]} contains search query path
         * @param {rustdoc.Row} row indexed item
         * @returns {null|number} edit distance
         */
        function checkRowPath(contains, row) {
            if (contains.length === 0) {
                return 0;
            }

            const path = row.modulePath.split("::");

            if (row.parent && row.parent.name) {
                path.push(row.parent.name.toLowerCase());
            }

            return checkPath(contains, path);
        }

        /**
         *
         * @param {number} filter
         * @param {rustdoc.ItemType} type
         * @returns
         */
        function typePassesFilter(filter, type) {
            // No filter or Exact mach
            if (filter <= NO_TYPE_FILTER || filter === type) return true;

            // Match related items
            const name = itemTypes[type];
            switch (itemTypes[filter]) {
                case "constant":
                    return name === "associatedconstant";
                case "fn":
                    return name === "method" || name === "tymethod";
                case "type":
                    return name === "primitive" || name === "associatedtype";
                case "trait":
                    return name === "traitalias";
            }

            // No match
            return false;
        }

        const innerRunNameQuery =
            /**
             * @this {DocSearch}
             * @param {string} currentCrate
             * @returns {AsyncGenerator<rustdoc.ResultObject>}
             */
            async function*(currentCrate) {
                const index = this.database.getIndex("normalizedName");
                if (!index) {
                    return;
                }
                const idDuplicates = new Set();
                const pathDuplicates = new Set();
                let count = 0;
                const prefixResults = [];
                const normalizedUserQuery = parsedQuery.userQuery
                    .replace(/[_"]/g, "")
                    .toLowerCase();
                /**
                 * @param {string} name
                 * @param {number} alias
                 * @param {number} dist
                 * @param {number} index
                 * @returns {Promise<rustdoc.PlainResultObject?>}
                 */
                const handleAlias = async(name, alias, dist, index) => {
                    return {
                        id: alias,
                        dist,
                        path_dist: 0,
                        index,
                        alias: name,
                        is_alias: true,
                        elems: [], // only used in type-based queries
                        returned: [], // only used in type-based queries
                        original: await this.getRow(alias),
                    };
                };
                /**
                 * @param {Promise<rustdoc.PlainResultObject|null>[]} data
                 * @returns {AsyncGenerator<rustdoc.ResultObject, boolean>}
                 */
                const flush = async function* (data) {
                    const satr = sortAndTransformResults(
                        await Promise.all(data),
                        null,
                        currentCrate,
                        pathDuplicates,
                    );
                    data.length = 0;
                    for await (const processed of satr) {
                        yield processed;
                        count += 1;
                        if ((count & 0x7F) === 0) {
                            await yieldToBrowser();
                        }
                        if (count >= MAX_RESULTS) {
                            return true;
                        }
                    }
                    return false;
                };
                const aliasResults = await index.search(normalizedUserQuery);
                if (aliasResults) {
                    for (const id of aliasResults.matches().entries()) {
                        const [name, alias] = await Promise.all([
                            this.getName(id),
                            this.getAliasTarget(id),
                        ]);
                        if (name !== null &&
                            alias !== null &&
                            !idDuplicates.has(id) &&
                            name.replace(/[_"]/g, "").toLowerCase() === normalizedUserQuery
                        ) {
                            prefixResults.push(handleAlias(name, alias, 0, 0));
                            idDuplicates.add(id);
                        }
                    }
                }
                if (parsedQuery.error !== null || parsedQuery.elems.length === 0) {
                    yield* flush(prefixResults);
                    return;
                }
                const elem = parsedQuery.elems[0];
                const typeFilter = itemTypeFromName(elem.typeFilter);
                /**
                 * @param {number} id
                 * @returns {Promise<rustdoc.PlainResultObject?>}
                 */
                const handleNameSearch = async id => {
                    const row = await this.getRow(id);
                    if (!row || !row.entry) {
                        return null;
                    }
                    if (!typePassesFilter(typeFilter, row.ty) ||
                        (filterCrates !== null && row.crate !== filterCrates)) {
                        return null;
                    }

                    /** @type {number|null} */
                    let pathDist = 0;
                    if (elem.fullPath.length > 1) {
                        pathDist = checkRowPath(elem.pathWithoutLast, row);
                        if (pathDist === null) {
                            return null;
                        }
                    }

                    if (parsedQuery.literalSearch) {
                        return row.name.toLowerCase() === elem.pathLast ? {
                            id,
                            dist: 0,
                            path_dist: 0,
                            index: 0,
                            elems: [], // only used in type-based queries
                            returned: [], // only used in type-based queries
                            is_alias: false,
                        } : null;
                    } else {
                        return {
                            id,
                            dist: editDistance(
                                row.normalizedName,
                                elem.normalizedPathLast,
                                maxEditDistance,
                            ),
                            path_dist: pathDist,
                            index: row.normalizedName.indexOf(elem.normalizedPathLast),
                            elems: [], // only used in type-based queries
                            returned: [], // only used in type-based queries
                            is_alias: false,
                        };
                    }
                };
                if (elem.normalizedPathLast === "") {
                    // faster full-table scan for this specific case.
                    const nameData = this.database.getData("name");
                    const l = nameData ? nameData.length : 0;
                    for (let id = 0; id < l; ++id) {
                        if (!idDuplicates.has(id)) {
                            idDuplicates.add(id);
                            prefixResults.push(handleNameSearch(id));
                        }
                        if (yield* flush(prefixResults)) {
                            return;
                        }
                    }
                    return;
                }
                const results = await index.search(elem.normalizedPathLast);
                if (results) {
                    for await (const result of results.prefixMatches()) {
                        for (const id of result.entries()) {
                            if (!idDuplicates.has(id)) {
                                idDuplicates.add(id);
                                prefixResults.push(handleNameSearch(id));
                                const [name, alias] = await Promise.all([
                                    this.getName(id),
                                    this.getAliasTarget(id),
                                ]);
                                if (name !== null && alias !== null) {
                                    prefixResults.push(handleAlias(name, alias, 0, 0));
                                }
                            }
                        }
                        if (yield* flush(prefixResults)) {
                            return;
                        }
                    }
                    if (yield* flush(prefixResults)) {
                        return;
                    }
                }
                const levSearchResults = index.searchLev(elem.normalizedPathLast);
                const levResults = [];
                for await (const levResult of levSearchResults) {
                    for (const id of levResult.matches().entries()) {
                        if (!idDuplicates.has(id)) {
                            idDuplicates.add(id);
                            levResults.push(handleNameSearch(id));
                            const [name, alias] = await Promise.all([
                                this.getName(id),
                                this.getAliasTarget(id),
                            ]);
                            if (name !== null && alias !== null) {
                                levResults.push(handleAlias(
                                    name,
                                    alias,
                                    editDistance(elem.normalizedPathLast, name, maxEditDistance),
                                    name.indexOf(elem.normalizedPathLast),
                                ));
                            }
                        }
                    }
                }
                yield* flush(levResults);
                if (results) {
                    const substringResults = [];
                    for await (const result of results.substringMatches()) {
                        for (const id of result.entries()) {
                            if (!idDuplicates.has(id)) {
                                idDuplicates.add(id);
                                substringResults.push(handleNameSearch(id));
                                const [name, alias] = await Promise.all([
                                    this.getName(id),
                                    this.getAliasTarget(id),
                                ]);
                                if (name !== null && alias !== null) {
                                    levResults.push(handleAlias(
                                        name,
                                        alias,
                                        editDistance(
                                            elem.normalizedPathLast,
                                            name,
                                            maxEditDistance,
                                        ),
                                        name.indexOf(elem.normalizedPathLast),
                                    ));
                                }
                            }
                        }
                        if (yield* flush(substringResults)) {
                            return;
                        }
                    }
                }
            }
            .bind(this);

        const innerRunTypeQuery =
            /**
             * @this {DocSearch}
             * @param {rustdoc.ParserQueryElement[]} inputs
             * @param {rustdoc.ParserQueryElement[]} output
             * @param {"sig"|"elems"|"returned"|null} typeInfo
             * @param {string} currentCrate
             * @returns {AsyncGenerator<rustdoc.ResultObject>}
             */
            async function*(inputs, output, typeInfo, currentCrate) {
                const index = this.database.getIndex("normalizedName");
                if (!index) {
                    return;
                }
                /** @type {Map<string, number>} */
                const genericMap = new Map();
                /**
                 * @template Q
                 * @typedef {{
                 *     invertedIndex: stringdex.RoaringBitmap[],
                 *     queryElem: Q,
                 * }} PostingsList
                 */
                /** @type {stringdex.RoaringBitmap[]} */
                const empty_inverted_index = [];
                /** @type {PostingsList<any>[]} */
                const empty_postings_list = [];
                /** @type {stringdex.RoaringBitmap[]} */
                const everything_inverted_index = [];
                for (let i = 0; i < 64; ++i) {
                    everything_inverted_index.push(RoaringBitmap.everything());
                }
                /**
                 * @type {PostingsList<rustdoc.QueryElement[]>}
                 */
                const everything_postings_list = {
                    invertedIndex: everything_inverted_index,
                    queryElem: [],
                };
                /**
                 * @type {PostingsList<rustdoc.QueryElement[]>[]}
                 */
                const nested_everything_postings_list = [everything_postings_list];
                /**
                 * @param {...stringdex.RoaringBitmap[]} idx
                 * @returns {stringdex.RoaringBitmap[]}
                 */
                const intersectInvertedIndexes = (...idx) => {
                    let i = 0;
                    const l = idx.length;
                    while (i < l - 1 && idx[i] === everything_inverted_index) {
                        i += 1;
                    }
                    const result = [...idx[i]];
                    for (; i < l; ++i) {
                        if (idx[i] === everything_inverted_index) {
                            continue;
                        }
                        if (idx[i].length < result.length) {
                            result.length = idx[i].length;
                        }
                        for (let j = 0; j < result.length; ++j) {
                            result[j] = result[j].intersection(idx[i][j]);
                        }
                    }
                    return result;
                };
                /**
                 * Fetch a bitmap of potentially-matching functions,
                 * plus a list of query elements annotated with the correct IDs.
                 *
                 * More than one ID can exist because, for example, q=`Iter` can match
                 * `std::vec::Iter`, or `std::btree_set::Iter`, or anything else, and those
                 * items different IDs. What's worse, q=`Iter<Iter>` has N**2 possible
                 * matches, because it could be `vec::Iter<btree_set::Iter>`,
                 * `btree_set::Iter<vec::Iter>`, `vec::Iter<vec::Iter>`,
                 * `btree_set::Iter<btree_set::Iter>`,
                 * or anything else. This function returns all possible permutations.
                 *
                 * @param {rustdoc.ParserQueryElement|null} elem
                 * @returns {Promise<PostingsList<rustdoc.QueryElement>[]>}
                 */
                const unpackPostingsList = async elem => {
                    if (!elem) {
                        return empty_postings_list;
                    }
                    const typeFilter = itemTypeFromName(elem.typeFilter);
                    const searchResults = await index.search(elem.normalizedPathLast);
                    /**
                     * @type {Promise<[
                     *     number,
                     *     string|null,
                     *     rustdoc.TypeData|null,
                     *     rustdoc.PathData|null,
                     * ]>[]}
                     * */
                    const typePromises = [];
                    if (typeFilter !== TY_GENERIC && searchResults) {
                        for (const id of searchResults.matches().entries()) {
                            typePromises.push(Promise.all([
                                this.getName(id),
                                this.getTypeData(id),
                                this.getPathData(id),
                            ]).then(([name, typeData, pathData]) =>
                                [id, name, typeData, pathData]));
                        }
                    }
                    const types = (await Promise.all(typePromises))
                        .filter(([_id, name, ty, path]) =>
                            name !== null && name.toLowerCase() === elem.pathLast &&
                            ty && !ty.invertedFunctionSignatureIndex.every(bitmap => {
                                return bitmap.isEmpty();
                            }) &&
                            path && path.ty !== TY_ASSOCTYPE &&
                            (elem.pathWithoutLast.length === 0 ||
                                checkPath(
                                    elem.pathWithoutLast,
                                    path.modulePath.split("::"),
                                ) === 0),
                            );
                    if (types.length === 0) {
                        const areGenericsAllowed = typeFilter === TY_GENERIC || (
                            typeFilter === -1 &&
                            (parsedQuery.totalElems > 1 || parsedQuery.hasReturnArrow) &&
                            elem.pathWithoutLast.length === 0 &&
                            elem.generics.length === 0 &&
                            elem.bindings.size === 0
                        );
                        if (typeFilter !== TY_GENERIC &&
                            (elem.name.length >= 3 || !areGenericsAllowed)
                        ) {
                            /** @type {string|null} */
                            let chosenName = null;
                            /** @type {rustdoc.TypeData[]} */
                            let chosenType = [];
                            /** @type {rustdoc.PathData[]} */
                            let chosenPath = [];
                            /** @type {number[]} */
                            let chosenId = [];
                            let chosenDist = Number.MAX_SAFE_INTEGER;
                            const levResults = index.searchLev(elem.normalizedPathLast);
                            for await (const searchResults of levResults) {
                                for (const id of searchResults.matches().entries()) {
                                    const [name, ty, path] = await Promise.all([
                                        this.getName(id),
                                        this.getTypeData(id),
                                        this.getPathData(id),
                                    ]);
                                    if (name !== null && ty !== null && path !== null &&
                                        !ty.invertedFunctionSignatureIndex.every(bitmap => {
                                            return bitmap.isEmpty();
                                        }) &&
                                        path.ty !== TY_ASSOCTYPE
                                    ) {
                                        let dist = editDistance(
                                            name,
                                            elem.pathLast,
                                            maxEditDistance,
                                        );
                                        if (elem.pathWithoutLast.length !== 0) {
                                            const pathDist = checkPath(
                                                elem.pathWithoutLast,
                                                path.modulePath.split("::"),
                                            );
                                            // guaranteed to be higher than the path limit
                                            dist += pathDist === null ?
                                                Number.MAX_SAFE_INTEGER :
                                                pathDist;
                                        }
                                        if (name === chosenName) {
                                            chosenId.push(id);
                                            chosenType.push(ty);
                                            chosenPath.push(path);
                                        } else if (dist < chosenDist) {
                                            chosenName = name;
                                            chosenId = [id];
                                            chosenType = [ty];
                                            chosenPath = [path];
                                            chosenDist = dist;
                                        }
                                    }
                                }
                                if (chosenId.length !== 0) {
                                    // searchLev returns results in order
                                    // if we have working matches, we're done
                                    break;
                                }
                            }
                            if (areGenericsAllowed) {
                                parsedQuery.proposeCorrectionFrom = elem.name;
                                parsedQuery.proposeCorrectionTo = chosenName;
                            } else {
                                parsedQuery.correction = chosenName;
                                for (let i = 0; i < chosenType.length; ++i) {
                                    types.push([
                                        chosenId[i],
                                        chosenName,
                                        chosenType[i],
                                        chosenPath[i],
                                    ]);
                                }
                            }
                        }
                        if (areGenericsAllowed) {
                            let genericId = genericMap.get(elem.normalizedPathLast);
                            if (genericId === undefined) {
                                genericId = genericMap.size;
                                genericMap.set(elem.normalizedPathLast, genericId);
                            }
                            return [{
                                invertedIndex: await this.getGenericInvertedIndex(genericId),
                                queryElem: {
                                    name: elem.name,
                                    id: (-genericId) - 1,
                                    typeFilter: TY_GENERIC,
                                    generics: [],
                                    bindings: EMPTY_BINDINGS_MAP,
                                    fullPath: elem.fullPath,
                                    pathLast: elem.pathLast,
                                    normalizedPathLast: elem.normalizedPathLast,
                                    pathWithoutLast: elem.pathWithoutLast,
                                },
                            }];
                        }
                    }
                    types.sort(([_i, name1, _t, pathData1], [_i2, name2, _t2, pathData2]) => {
                        const p1 = !pathData1 ? "" : pathData1.modulePath;
                        const p2 = !pathData2 ? "" : pathData2.modulePath;
                        const n1 = name1 === null ? "" : name1;
                        const n2 = name2 === null ? "" : name2;
                        if (p1.length !== p2.length) {
                            return p1.length > p2.length ? +1 : -1;
                        }
                        if (n1.length !== n2.length) {
                            return n1.length > n2.length ? +1 : -1;
                        }
                        if (n1 !== n2) {
                            return n1 > n2 ? +1 : -1;
                        }
                        if (p1 !== p2) {
                            return p1 > p2 ? +1 : -1;
                        }
                        return 0;
                    });
                    /** @type {PostingsList<rustdoc.QueryElement>[]} */
                    const results = [];
                    for (const [id, _name, typeData] of types) {
                        if (!typeData || typeData.invertedFunctionSignatureIndex.every(bitmap => {
                            return bitmap.isEmpty();
                        })) {
                            continue;
                        }
                        const upla = await unpackPostingsListAll(elem.generics);
                        const uplb = await unpackPostingsListBindings(elem.bindings);
                        for (const {invertedIndex: genericsIdx, queryElem: generics} of upla) {
                            for (const {invertedIndex: bindingsIdx, queryElem: bindings} of uplb) {
                                results.push({
                                    invertedIndex: intersectInvertedIndexes(
                                        typeData.invertedFunctionSignatureIndex,
                                        genericsIdx,
                                        bindingsIdx,
                                    ),
                                    queryElem: {
                                        name: elem.name,
                                        id,
                                        typeFilter,
                                        generics,
                                        bindings,
                                        fullPath: elem.fullPath,
                                        pathLast: elem.pathLast,
                                        normalizedPathLast: elem.normalizedPathLast,
                                        pathWithoutLast: elem.pathWithoutLast,
                                    },
                                });
                                if ((results.length & 0x7F) === 0) {
                                    await yieldToBrowser();
                                }
                            }
                        }
                    }
                    return results;
                };
                /**
                 * Fetch all possible matching permutations of a list of query elements.
                 *
                 * The empty list returns an "identity postings list", with a bitmap that
                 * matches everything and an empty list of elems. This allows you to safely
                 * take the intersection of this bitmap.
                 *
                 * @param {(rustdoc.ParserQueryElement|null)[]|null} elems
                 * @returns {Promise<PostingsList<rustdoc.QueryElement[]>[]>}
                 */
                const unpackPostingsListAll = async elems => {
                    if (!elems || elems.length === 0) {
                        return nested_everything_postings_list;
                    }
                    const [firstPostingsList, remainingAll] = await Promise.all([
                        unpackPostingsList(elems[0]),
                        unpackPostingsListAll(elems.slice(1)),
                    ]);
                    /** @type {PostingsList<rustdoc.QueryElement[]>[]} */
                    const results = [];
                    for (const {
                        invertedIndex: firstIdx,
                        queryElem: firstElem,
                    } of firstPostingsList) {
                        for (const {
                            invertedIndex: remainingIdx,
                            queryElem: remainingElems,
                        } of remainingAll) {
                            results.push({
                                invertedIndex: intersectInvertedIndexes(firstIdx, remainingIdx),
                                queryElem: [firstElem, ...remainingElems],
                            });
                            if ((results.length & 0x7F) === 0) {
                                await yieldToBrowser();
                            }
                        }
                    }
                    return results;
                };
                /**
                 * Fetch all possible matching permutations of a map query element bindings.
                 *
                 * The empty list returns an "identity postings list", with a bitmap that
                 * matches everything and an empty list of elems. This allows you to safely
                 * take the intersection of this bitmap.
                 *
                 * Heads up! This function mutates the Map that you provide.
                 * Before passing an actual parser item to it, make sure to clone the map.
                 *
                 * @param {Map<string, rustdoc.ParserQueryElement[]>} elems
                 * @returns {Promise<PostingsList<
                 *     Map<number, rustdoc.QueryElement[]>,
                 * >[]>}
                 */
                const unpackPostingsListBindings = async elems => {
                    if (!elems) {
                        return [{
                            invertedIndex: everything_inverted_index,
                            queryElem: new Map(),
                        }];
                    }
                    const firstKey = elems.keys().next().value;
                    if (firstKey === undefined) {
                        return [{
                            invertedIndex: everything_inverted_index,
                            queryElem: new Map(),
                        }];
                    }
                    const firstList = elems.get(firstKey);
                    if (firstList === undefined) {
                        return [{
                            invertedIndex: everything_inverted_index,
                            queryElem: new Map(),
                        }];
                    }
                    const firstKeyIds = await index.search(firstKey);
                    if (!firstKeyIds) {
                        // User specified a non-existent key.
                        return [{
                            invertedIndex: empty_inverted_index,
                            queryElem: new Map(),
                        }];
                    }
                    elems.delete(firstKey);
                    const [firstPostingsList, remainingAll] = await Promise.all([
                        unpackPostingsListAll(firstList),
                        unpackPostingsListBindings(elems),
                    ]);
                    /** @type {PostingsList<Map<number, rustdoc.QueryElement[]>>[]} */
                    const results = [];
                    for (const keyId of firstKeyIds.matches().entries()) {
                        for (const {
                            invertedIndex: firstIdx,
                            queryElem: firstElem,
                        } of firstPostingsList) {
                            for (const {
                                invertedIndex: remainingIdx,
                                queryElem: remainingElems,
                            } of remainingAll) {
                                const elems = new Map(remainingElems);
                                elems.set(keyId, firstElem);
                                results.push({
                                    invertedIndex: intersectInvertedIndexes(firstIdx, remainingIdx),
                                    queryElem: elems,
                                });
                                if ((results.length & 0x7F) === 0) {
                                    await yieldToBrowser();
                                }
                            }
                        }
                    }
                    elems.set(firstKey, firstList);
                    if (results.length === 0) {
                        // User specified a non-existent key.
                        return [{
                            invertedIndex: empty_inverted_index,
                            queryElem: new Map(),
                        }];
                    }
                    return results;
                };

                // finally, we can do the actual unification loop
                const [allInputs, allOutput] = await Promise.all([
                    unpackPostingsListAll(inputs),
                    unpackPostingsListAll(output),
                ]);
                let checkCounter = 0;
                /**
                 * Finally, we can perform an incremental search, sorted by the number of
                 * entries that match a given query.
                 *
                 * The outer list gives the number of elements. The inner one is separate
                 * for each distinct name resolution.
                 *
                 * @type {{
                 *     bitmap: stringdex.RoaringBitmap,
                 *     inputs: rustdoc.QueryElement[],
                 *     output: rustdoc.QueryElement[],
                 * }[][]}
                 */
                const queryPlan = [];
                for (const {invertedIndex: inputsIdx, queryElem: inputs} of allInputs) {
                    for (const {invertedIndex: outputIdx, queryElem: output} of allOutput) {
                        const invertedIndex = intersectInvertedIndexes(inputsIdx, outputIdx);
                        for (const [size, bitmap] of invertedIndex.entries()) {
                            checkCounter += 1;
                            if ((checkCounter & 0x7F) === 0) {
                                await yieldToBrowser();
                            }
                            if (!queryPlan[size]) {
                                queryPlan[size] = [];
                            }
                            queryPlan[size].push({
                                bitmap, inputs, output,
                            });
                        }
                    }
                }
                const resultPromises = [];
                const dedup = new Set();
                let resultCounter = 0;
                const isReturnTypeQuery = inputs.length === 0;
                /** @type {rustdoc.PlainResultObject[]} */
                const pushToBottom = [];
                plan: for (const queryStep of queryPlan) {
                    for (const {bitmap, inputs, output} of queryStep) {
                        for (const id of bitmap.entries()) {
                            checkCounter += 1;
                            if ((checkCounter & 0x7F) === 0) {
                                await yieldToBrowser();
                            }
                            resultPromises.push(this.getFunctionData(id).then(async fnData => {
                                if (!fnData || !fnData.functionSignature) {
                                    return null;
                                }
                                checkCounter += 1;
                                if ((checkCounter & 0x7F) === 0) {
                                    await yieldToBrowser();
                                }
                                const functionSignature = fnData.functionSignature;
                                if (!unifyFunctionTypes(
                                    functionSignature.inputs,
                                    inputs,
                                    functionSignature.where_clause,
                                    null,
                                    mgens => {
                                        return !!unifyFunctionTypes(
                                            functionSignature.output,
                                            output,
                                            functionSignature.where_clause,
                                            mgens,
                                            checkTypeMgensForConflict,
                                            0, // unboxing depth
                                        );
                                    },
                                    0, // unboxing depth
                                )) {
                                    return null;
                                }
                                const result = {
                                    id,
                                    dist: fnData.elemCount,
                                    path_dist: 0,
                                    index: -1,
                                    elems: inputs,
                                    returned: output,
                                    is_alias: false,
                                };
                                const entry = await this.getEntryData(id);
                                if ((entry && !isFnLikeTy(entry.ty)) ||
                                    (isReturnTypeQuery &&
                                        functionSignature &&
                                        containsTypeFromQuery(
                                            output,
                                            functionSignature.inputs,
                                            functionSignature.where_clause,
                                        )
                                    )
                                ) {
                                    pushToBottom.push(result);
                                    return null;
                                }
                                return result;
                            }));
                        }
                    }
                    for await (const result of sortAndTransformResults(
                        await Promise.all(resultPromises),
                        typeInfo,
                        currentCrate,
                        dedup,
                    )) {
                        if (resultCounter >= MAX_RESULTS) {
                            break plan;
                        }
                        yield result;
                        resultCounter += 1;
                    }
                    resultPromises.length = 0;
                }
                if (resultCounter >= MAX_RESULTS) {
                    return;
                }
                for await (const result of sortAndTransformResults(
                    await Promise.all(pushToBottom),
                    typeInfo,
                    currentCrate,
                    dedup,
                )) {
                    if (resultCounter >= MAX_RESULTS) {
                        break;
                    }
                    yield result;
                    resultCounter += 1;
                }
            }
            .bind(this);

        if (parsedQuery.foundElems === 1 && !parsedQuery.hasReturnArrow) {
            // We never want the main tab to delay behind the other two tabs.
            // This is a bit of a hack (because JS's scheduler doesn't have much of an API),
            // along with making innerRunTypeQuery yield to the UI thread.
            const {
                promise: donePromise,
                resolve: doneResolve,
                reject: doneReject,
            } = Promise.withResolvers();
            const doneTimeout = timeout(250);
            return {
                "in_args": (async function*() {
                    await Promise.race([donePromise, doneTimeout]);
                    yield* innerRunTypeQuery(parsedQuery.elems, [], "elems", currentCrate);
                })(),
                "returned": (async function*() {
                    await Promise.race([donePromise, doneTimeout]);
                    yield* innerRunTypeQuery([], parsedQuery.elems, "returned", currentCrate);
                })(),
                "others": (async function*() {
                    try {
                        yield* innerRunNameQuery(currentCrate);
                        doneResolve(null);
                    } catch (e) {
                        doneReject(e);
                        throw e;
                    }
                })(),
                "query": parsedQuery,
            };
        } else if (parsedQuery.error !== null) {
            return {
                "in_args": (async function*() {})(),
                "returned": (async function*() {})(),
                "others": innerRunNameQuery(currentCrate),
                "query": parsedQuery,
            };
        } else {
            const typeInfo = parsedQuery.elems.length === 0 ?
                "returned" : (
                    parsedQuery.returned.length === 0 ? "elems" : "sig"
                );
            return {
                "in_args": (async function*() {})(),
                "returned": (async function*() {})(),
                "others": parsedQuery.foundElems === 0 ?
                    (async function*() {})() :
                    innerRunTypeQuery(
                        parsedQuery.elems,
                        parsedQuery.returned,
                        typeInfo,
                        currentCrate,
                    ),
                "query": parsedQuery,
            };
        }
    }
}


// ==================== Core search logic end ====================

/** @type {DocSearch} */
let docSearch;
const longItemTypes = [
    "keyword",
    "primitive type",
    "module",
    "extern crate",
    "re-export",
    "struct",
    "enum",
    "function",
    "type alias",
    "static",
    "trait",
    "",
    "trait method",
    "method",
    "struct field",
    "enum variant",
    "macro",
    "assoc type",
    "constant",
    "assoc const",
    "union",
    "foreign type",
    "existential type",
    "attribute macro",
    "derive macro",
    "trait alias",
];
// @ts-expect-error
let currentResults;

// In the search display, allows to switch between tabs.
// @ts-expect-error
function printTab(nb) {
    let iter = 0;
    let foundCurrentTab = false;
    let foundCurrentResultSet = false;
    // @ts-expect-error
    onEachLazy(document.getElementById("search-tabs").childNodes, elem => {
        if (nb === iter) {
            addClass(elem, "selected");
            foundCurrentTab = true;
        } else {
            removeClass(elem, "selected");
        }
        iter += 1;
    });
    const isTypeSearch = (nb > 0 || iter === 1);
    iter = 0;
    // @ts-expect-error
    onEachLazy(document.getElementById("results").childNodes, elem => {
        if (nb === iter) {
            addClass(elem, "active");
            foundCurrentResultSet = true;
        } else {
            removeClass(elem, "active");
        }
        iter += 1;
    });
    if (foundCurrentTab && foundCurrentResultSet) {
        searchState.currentTab = nb;
        // Corrections only kick in on type-based searches.
        const correctionsElem = document.getElementsByClassName("search-corrections");
        if (isTypeSearch) {
            removeClass(correctionsElem[0], "hidden");
        } else {
            addClass(correctionsElem[0], "hidden");
        }
    } else if (nb !== 0) {
        printTab(0);
    }
}

/**
 * Build an URL with search parameters.
 *
 * @param {string} search            - The current search being performed.
 * @param {string|null} filterCrates - The current filtering crate (if any).
 *
 * @return {string}
 */
function buildUrl(search, filterCrates) {
    let extra = "?search=" + encodeURIComponent(search);

    if (filterCrates !== null) {
        extra += "&filter-crate=" + encodeURIComponent(filterCrates);
    }
    return getNakedUrl() + extra + window.location.hash;
}

/**
 * Return the filtering crate or `null` if there is none.
 *
 * @return {string|null}
 */
function getFilterCrates() {
    const elem = document.getElementById("crate-search");

    // @ts-expect-error
    if (elem && elem.value !== "all crates") {
        // @ts-expect-error
        return elem.value;
    }
    return null;
}

// @ts-expect-error
function nextTab(direction) {
    const next = (searchState.currentTab + direction + 3) % searchState.focusedByTab.length;
    window.searchState.focusedByTab[searchState.currentTab] = document.activeElement;
    printTab(next);
    focusSearchResult();
}

// Focus the first search result on the active tab, or the result that
// was focused last time this tab was active.
function focusSearchResult() {
    const target = searchState.focusedByTab[searchState.currentTab] ||
        document.querySelectorAll(".search-results.active a").item(0) ||
        document.querySelectorAll("#search-tabs button").item(searchState.currentTab);
    searchState.focusedByTab[searchState.currentTab] = null;
    if (target && target instanceof HTMLElement) {
        target.focus();
    }
}

/**
 * Render a set of search results for a single tab.
 * @param {AsyncGenerator<rustdoc.ResultObject>} results   - The search results for this tab
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {boolean}     display - True if this is the active tab
 * @param {function(number, HTMLElement): any} finishedCallback
 * @param {boolean} isTypeSearch
 * @returns {Promise<HTMLElement>}
 */
async function addTab(results, query, display, finishedCallback, isTypeSearch) {
    const extraClass = display ? " active" : "";

    /** @type {HTMLElement} */
    let output = document.createElement("ul");
    output.className = "search-results " + extraClass;

    let count = 0;

    /** @type {Promise<string|null>[]} */
    const descList = [];

    /** @param {rustdoc.ResultObject} obj */
    const addNextResultToOutput = async obj => {
        count += 1;

        const name = obj.item.name;
        const type = itemTypes[obj.item.ty];
        const longType = longItemTypes[obj.item.ty];
        const typeName = longType.length !== 0 ? `${longType}` : "?";

        const link = document.createElement("a");
        link.className = "result-" + type;
        link.href = obj.href;

        const resultName = document.createElement("span");
        resultName.className = "result-name";

        resultName.insertAdjacentHTML(
            "beforeend",
            `<span class="typename">${typeName}</span>`);
        link.appendChild(resultName);

        let alias = " ";
        if (obj.alias !== undefined) {
            alias = ` <div class="alias">\
<b>${obj.alias}</b><i class="grey">&nbsp;- see&nbsp;</i>\
</div>`;
        }
        resultName.insertAdjacentHTML(
            "beforeend",
            `<div class="path">${alias}\
${obj.displayPath}<span class="${type}">${name}</span>\
</div>`);

        const description = document.createElement("div");
        description.className = "desc";
        obj.desc.then(desc => {
            if (desc !== null) {
                description.insertAdjacentHTML("beforeend", desc);
            }
        });
        descList.push(obj.desc);
        if (obj.displayTypeSignature) {
            const {type, mappedNames, whereClause} = await obj.displayTypeSignature;
            const displayType = document.createElement("div");
            type.forEach((value, index) => {
                if (index % 2 !== 0) {
                    const highlight = document.createElement("strong");
                    highlight.appendChild(document.createTextNode(value));
                    displayType.appendChild(highlight);
                } else {
                    displayType.appendChild(document.createTextNode(value));
                }
            });
            if (mappedNames.size > 0 || whereClause.size > 0) {
                let addWhereLineFn = () => {
                    const line = document.createElement("div");
                    line.className = "where";
                    line.appendChild(document.createTextNode("where"));
                    displayType.appendChild(line);
                    addWhereLineFn = () => {};
                };
                for (const [qname, name] of mappedNames) {
                    // don't care unless the generic name is different
                    if (name === qname) {
                        continue;
                    }
                    addWhereLineFn();
                    const line = document.createElement("div");
                    line.className = "where";
                    line.appendChild(document.createTextNode(`    ${qname} matches `));
                    const lineStrong = document.createElement("strong");
                    lineStrong.appendChild(document.createTextNode(name));
                    line.appendChild(lineStrong);
                    displayType.appendChild(line);
                }
                for (const [name, innerType] of whereClause) {
                    // don't care unless there's at least one highlighted entry
                    if (innerType.length <= 1) {
                        continue;
                    }
                    addWhereLineFn();
                    const line = document.createElement("div");
                    line.className = "where";
                    line.appendChild(document.createTextNode(`    ${name}: `));
                    innerType.forEach((value, index) => {
                        if (index % 2 !== 0) {
                            const highlight = document.createElement("strong");
                            highlight.appendChild(document.createTextNode(value));
                            line.appendChild(highlight);
                        } else {
                            line.appendChild(document.createTextNode(value));
                        }
                    });
                    displayType.appendChild(line);
                }
            }
            displayType.className = "type-signature";
            link.appendChild(displayType);
        }

        link.appendChild(description);
        output.appendChild(link);

        results.next().then(async nextResult => {
            if (nextResult.value) {
                addNextResultToOutput(nextResult.value);
            } else {
                await Promise.all(descList);
                // need to make sure the element is shown before
                // running this callback
                yieldToBrowser().then(() => finishedCallback(count, output));
            }
        });
    };
    const firstResult = await results.next();
    let correctionOutput = "";
    if (query.correction !== null && isTypeSearch) {
        const orig = query.returned.length > 0
            ? query.returned[0].name
            : query.elems[0].name;
        correctionOutput = "<h3 class=\"search-corrections\">" +
            `Type "${orig}" not found. ` +
            "Showing results for closest type name " +
            `"${query.correction}" instead.</h3>`;
    }
    if (query.proposeCorrectionFrom !== null && isTypeSearch) {
        const orig = query.proposeCorrectionFrom;
        const targ = query.proposeCorrectionTo;
        correctionOutput = "<h3 class=\"search-corrections\">" +
            `Type "${orig}" not found and used as generic parameter. ` +
            `Consider searching for "${targ}" instead.</h3>`;
    }
    if (firstResult.value) {
        if (correctionOutput !== "") {
            const h3 = document.createElement("h3");
            h3.innerHTML = correctionOutput;
            output.appendChild(h3);
        }
        await addNextResultToOutput(firstResult.value);
    } else {
        output = document.createElement("div");
        if (correctionOutput !== "") {
            const h3 = document.createElement("h3");
            h3.innerHTML = correctionOutput;
            output.appendChild(h3);
        }
        output.className = "search-failed" + extraClass;
        const dlroChannel = `https://doc.rust-lang.org/${getVar("channel")}`;
        if (query.userQuery !== "") {
            output.innerHTML += "No results :(<br/>" +
            "Try on <a href=\"https://duckduckgo.com/?q=" +
            encodeURIComponent("rust " + query.userQuery) +
            "\">DuckDuckGo</a>?<br/><br/>" +
            "Or try looking in one of these:<ul><li>The <a " +
            `href="${dlroChannel}/reference/index.html">Rust Reference</a> ` +
            " for technical details about the language.</li><li><a " +
            `href="${dlroChannel}/rust-by-example/index.html">Rust By ` +
            "Example</a> for expository code examples.</a></li><li>The <a " +
            `href="${dlroChannel}/book/index.html">Rust Book</a> for ` +
            "introductions to language features and the language itself.</li><li><a " +
            "href=\"https://docs.rs\">Docs.rs</a> for documentation of crates released on" +
            " <a href=\"https://crates.io/\">crates.io</a>.</li></ul>";
        }
        output.innerHTML += "Example searches:<ul>" +
            "<li><a href=\"" + getNakedUrl() + "?search=std::vec\">std::vec</a></li>" +
            "<li><a href=\"" + getNakedUrl() + "?search=u32+->+bool\">u32 -> bool</a></li>" +
            "<li><a href=\"" + getNakedUrl() + "?search=Option<T>,+(T+->+U)+->+Option<U>\">" +
                "Option&lt;T>, (T -> U) -> Option&lt;U></a></li>" +
            "</ul>";
        // need to make sure the element is shown before
        // running this callback
        yieldToBrowser().then(() => finishedCallback(0, output));
    }
    return output;
}

/**
 * returns [tab, output]
 * @param {number} tabNb
 * @param {string} text
 * @param {AsyncGenerator<rustdoc.ResultObject>} results
 * @param {rustdoc.ParsedQuery<rustdoc.ParserQueryElement>} query
 * @param {boolean} isTypeSearch
 * @param {boolean} goToFirst
 * @returns {[HTMLElement, Promise<HTMLElement>]}
 */
function makeTab(tabNb, text, results, query, isTypeSearch, goToFirst) {
    const isCurrentTab = window.searchState.currentTab === tabNb;
    const tabButton = document.createElement("button");
    tabButton.appendChild(document.createTextNode(text));
    tabButton.className = isCurrentTab ? "selected" : "";
    const tabCount = document.createElement("span");
    tabCount.className = "count loading";
    tabCount.innerHTML = "\u{2007}(\u{2007})\u{2007}\u{2007}";
    tabButton.appendChild(tabCount);
    return [
        tabButton,
        addTab(results, query, isCurrentTab, (count, output) => {
            const search = window.searchState.outputElement();
            const error = query.error;
            if (count === 0 && error !== null && search) {
                error.forEach((value, index) => {
                    value = value.split("<").join("&lt;").split(">").join("&gt;");
                    if (index % 2 !== 0) {
                        error[index] = `<code>${value.replaceAll(" ", "&nbsp;")}</code>`;
                    } else {
                        error[index] = value;
                    }
                });
                const errorReport = document.createElement("h3");
                errorReport.className = "error";
                errorReport.innerHTML = `Query parser error: "${error.join("")}".`;
                search.insertBefore(errorReport, search.firstElementChild);
            } else if (goToFirst ||
                (count === 1 && getSettingValue("go-to-only-result") === "true")
            ) {
                // Needed to force re-execution of JS when coming back to a page. Let's take this
                // scenario as example:
                //
                // 1. You have the "Directly go to item in search if there is only one result"
                //    option enabled.
                // 2. You make a search which results only one result, leading you automatically to
                //    this result.
                // 3. You go back to previous page.
                //
                // Now, without the call below, the JS will not be re-executed and the previous
                // state will be used, starting search again since the search input is not empty,
                // leading you back to the previous page again.
                window.onunload = () => { };
                window.searchState.removeQueryParameters();
                const a = output.querySelector("a");
                if (a) {
                    a.click();
                    return;
                }
            }

            // https://blog.horizon-eda.org/misc/2020/02/19/ui.html
            //
            // CSS runs with `font-variant-numeric: tabular-nums` to ensure all
            // digits are the same width. \u{2007} is a Unicode space character
            // that is defined to be the same width as a digit.
            const fmtNbElems =
                count < 10  ? `\u{2007}(${count})\u{2007}\u{2007}` :
                count < 100 ? `\u{2007}(${count})\u{2007}` : `\u{2007}(${count})`;
            tabCount.innerHTML = fmtNbElems;
            tabCount.className = "count";
        }, isTypeSearch),
    ];
}

/**
 * @param {DocSearch} docSearch
 * @param {rustdoc.ResultsTable} results
 * @param {boolean} goToFirst
 * @param {string} filterCrates
 */
async function showResults(docSearch, results, goToFirst, filterCrates) {
    const search = window.searchState.outputElement();

    if (!search) {
        return;
    }

    let crates = "";
    const crateNames = await docSearch.getCrateNameList();
    if (crateNames.length > 1) {
        crates = "&nbsp;in&nbsp;<div id=\"crate-search-div\">" +
            "<select id=\"crate-search\"><option value=\"all crates\">all crates</option>";
        const l = crateNames.length;
        for (let i = 0; i < l; i += 1) {
            const c = crateNames[i];
            crates += `<option value="${c}" ${c === filterCrates && "selected"}>${c}</option>`;
        }
        crates += "</select></div>";
    }
    nonnull(document.querySelector(".search-switcher")).innerHTML = `Search results${crates}`;

    /** @type {[HTMLElement, Promise<HTMLElement>][]} */
    const tabs = [];
    searchState.currentTab = 0;
    if (results.query.error !== null) {
        tabs.push(makeTab(0, "In Names", results.others, results.query, false, goToFirst));
    } else if (
        results.query.foundElems <= 1 &&
        results.query.returned.length === 0 &&
        !results.query.hasReturnArrow
    ) {
        tabs.push(makeTab(0, "In Names", results.others, results.query, false, goToFirst));
        tabs.push(makeTab(1, "In Parameters", results.in_args, results.query, true, false));
        tabs.push(makeTab(2, "In Return Types", results.returned, results.query, true, false));
    } else {
        const signatureTabTitle =
            results.query.elems.length === 0 ? "In Function Return Types" :
                results.query.returned.length === 0 ? "In Function Parameters" :
                    "In Function Signatures";
        tabs.push(makeTab(0, signatureTabTitle, results.others, results.query, true, goToFirst));
    }

    const tabsElem = document.createElement("div");
    tabsElem.id = "search-tabs";

    const resultsElem = document.createElement("div");
    resultsElem.id = "results";

    search.innerHTML = "";
    for (const [tab, output] of tabs) {
        tabsElem.appendChild(tab);
        const placeholder = document.createElement("div");
        output.then(output => {
            if (placeholder.parentElement) {
                placeholder.parentElement.replaceChild(output, placeholder);
            }
        });
        resultsElem.appendChild(placeholder);
    }

    if (window.searchState.rustdocToolbar) {
        nonnull(
            nonnull(window.searchState.containerElement())
                .querySelector(".main-heading"),
        ).appendChild(window.searchState.rustdocToolbar);
    }
    const crateSearch = document.getElementById("crate-search");
    if (crateSearch) {
        crateSearch.addEventListener("input", updateCrate);
    }
    search.appendChild(tabsElem);
    search.appendChild(resultsElem);
    // Reset focused elements.
    window.searchState.showResults();
    window.searchState.focusedByTab = [null, null, null];
    let i = 0;
    for (const elem of tabsElem.childNodes) {
        const j = i;
        // @ts-expect-error
        elem.onclick = () => printTab(j);
        window.searchState.focusedByTab[i] = null;
        i += 1;
    }
    printTab(0);
}

// @ts-expect-error
function updateSearchHistory(url) {
    const btn = document.querySelector("#search-button a");
    if (btn instanceof HTMLAnchorElement) {
        btn.href = url;
    }
    if (!browserSupportsHistoryApi()) {
        return;
    }
    const params = searchState.getQueryStringParams();
    if (!history.state && params.search === undefined) {
        history.pushState(null, "", url);
    } else {
        history.replaceState(null, "", url);
    }
}

/**
 * Perform a search based on the current state of the search input element
 * and display the results.
 * @param {boolean} [forced]
 */
async function search(forced) {
    const query = DocSearch.parseQuery(nonnull(window.searchState.inputElement()).value.trim());

    let filterCrates = getFilterCrates();

    // @ts-expect-error
    if (!forced && query.userQuery === currentResults) {
        if (query.userQuery.length > 0) {
            putBackSearch();
        }
        return;
    }
    currentResults = query.userQuery;

    searchState.setLoadingSearch();

    const params = searchState.getQueryStringParams();

    // In case we have no information about the saved crate and there is a URL query parameter,
    // we override it with the URL query parameter.
    if (filterCrates === null && params["filter-crate"] !== undefined) {
        filterCrates = params["filter-crate"];
    }

    if (filterCrates !== null &&
        (await docSearch.getCrateNameList()).indexOf(filterCrates) === -1
    ) {
        filterCrates = null;
    }

    // Update document title to maintain a meaningful browser history
    searchState.title = "\"" + query.userQuery + "\" Search - Rust";

    // Because searching is incremental by character, only the most
    // recent search query is added to the browser history.
    updateSearchHistory(buildUrl(query.userQuery, filterCrates));

    await showResults(
        docSearch,
        // @ts-expect-error
        await docSearch.execQuery(query, filterCrates, window.currentCrate),
        params.go_to_first,
        // @ts-expect-error
        filterCrates);
}

/**
 * Callback for when the search form is submitted.
 * @param {Event} [e] - The event that triggered this call, if any
 */
function onSearchSubmit(e) {
    // @ts-expect-error
    e.preventDefault();
    searchState.clearInputTimeout();
    search();
}

function putBackSearch() {
    const search_input = window.searchState.inputElement();
    if (!search_input) {
        return;
    }
    if (search_input.value !== "" && !searchState.isDisplayed()) {
        searchState.showResults();
        if (browserSupportsHistoryApi()) {
            history.replaceState(null, "",
                buildUrl(search_input.value, getFilterCrates()));
        }
        document.title = searchState.title;
    }
}

function registerSearchEvents() {
    const params = searchState.getQueryStringParams();

    // Populate search bar with query string search term when provided,
    // but only if the input bar is empty. This avoid the obnoxious issue
    // where you start trying to do a search, and the index loads, and
    // suddenly your search is gone!
    const inputElement = nonnull(window.searchState.inputElement());
    if (inputElement.value === "") {
        inputElement.value = params.search || "";
    }

    const searchAfter500ms = () => {
        searchState.clearInputTimeout();
        window.searchState.timeout = setTimeout(search, 500);
    };
    inputElement.onkeyup = searchAfter500ms;
    inputElement.oninput = searchAfter500ms;
    if (inputElement.form) {
        inputElement.form.onsubmit = onSearchSubmit;
    }
    inputElement.onchange = e => {
        if (e.target !== document.activeElement) {
            // To prevent doing anything when it's from a blur event.
            return;
        }
        // Do NOT e.preventDefault() here. It will prevent pasting.
        searchState.clearInputTimeout();
        // zero-timeout necessary here because at the time of event handler execution the
        // pasted content is not in the input field yet. Shouldn’t make any difference for
        // change, though.
        setTimeout(search, 0);
    };
    inputElement.onpaste = inputElement.onchange;

    // @ts-expect-error
    searchState.outputElement().addEventListener("keydown", e => {
        if (!(e instanceof KeyboardEvent)) {
            return;
        }
        // We only handle unmodified keystrokes here. We don't want to interfere with,
        // for instance, alt-left and alt-right for history navigation.
        if (e.altKey || e.ctrlKey || e.shiftKey || e.metaKey) {
            return;
        }
        // up and down arrow select next/previous search result, or the
        // search box if we're already at the top.
        if (e.which === 38) { // up
            // @ts-expect-error
            const previous = document.activeElement.previousElementSibling;
            if (previous) {
                // @ts-expect-error
                previous.focus();
            } else {
                searchState.focus();
            }
            e.preventDefault();
        } else if (e.which === 40) { // down
            // @ts-expect-error
            const next = document.activeElement.nextElementSibling;
            if (next) {
                // @ts-expect-error
                next.focus();
            }
            // @ts-expect-error
            const rect = document.activeElement.getBoundingClientRect();
            if (window.innerHeight - rect.bottom < rect.height) {
                window.scrollBy(0, rect.height);
            }
            e.preventDefault();
        } else if (e.which === 37) { // left
            nextTab(-1);
            e.preventDefault();
        } else if (e.which === 39) { // right
            nextTab(1);
            e.preventDefault();
        }
    });

    inputElement.addEventListener("keydown", e => {
        if (e.which === 40) { // down
            focusSearchResult();
            e.preventDefault();
        }
    });

    inputElement.addEventListener("focus", () => {
        putBackSearch();
    });
}

// @ts-expect-error
function updateCrate(ev) {
    if (ev.target.value === "all crates") {
        // If we don't remove it from the URL, it'll be picked up again by the search.
        const query = nonnull(window.searchState.inputElement()).value.trim();
        updateSearchHistory(buildUrl(query, null));
    }
    // In case you "cut" the entry from the search input, then change the crate filter
    // before paste back the previous search, you get the old search results without
    // the filter. To prevent this, we need to remove the previous results.
    currentResults = null;
    search(true);
}

// eslint-disable-next-line max-len
// polyfill https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/fromBase64
/**
 * @type {function(string): Uint8Array} base64
 */
//@ts-expect-error
const makeUint8ArrayFromBase64 = Uint8Array.fromBase64 ? Uint8Array.fromBase64 : (string => {
    const bytes_as_string = atob(string);
    const l = bytes_as_string.length;
    const bytes = new Uint8Array(l);
    for (let i = 0; i < l; ++i) {
        bytes[i] = bytes_as_string.charCodeAt(i);
    }
    return bytes;
});


if (ROOT_PATH === null) {
    return;
}
const database = await Stringdex.loadDatabase(hooks);
if (typeof window !== "undefined") {
    docSearch = new DocSearch(ROOT_PATH, database);
    await docSearch.buildIndex();
    onEachLazy(document.querySelectorAll(
        ".search-form.loading",
    ), form => {
        removeClass(form, "loading");
    });
    registerSearchEvents();
    // If there's a search term in the URL, execute the search now.
    if (window.searchState.getQueryStringParams().search !== undefined) {
        search();
    }
} else if (typeof exports !== "undefined") {
    docSearch = new DocSearch(ROOT_PATH, database);
    await docSearch.buildIndex();
    return { docSearch, DocSearch };
}
};

if (typeof window !== "undefined") {
    const ROOT_PATH = window.rootPath;
    /** @type {stringdex.Callbacks|null} */
    let databaseCallbacks = null;
    initSearch(window.Stringdex, window.RoaringBitmap, {
        loadRoot: callbacks => {
            for (const key in callbacks) {
                if (Object.hasOwn(callbacks, key)) {
                    // @ts-ignore
                    window[key] = callbacks[key];
                }
            }
            databaseCallbacks = callbacks;
            // search.index/root is loaded by main.js, so
            // this script doesn't need to launch it, but
            // must pick it up
            // @ts-ignore
            if (window.searchIndex) {
                // @ts-ignore
                window.rr_(window.searchIndex);
            }
        },
        loadTreeByHash: hashHex => {
            const script = document.createElement("script");
            script.src = `${ROOT_PATH}search.index/${hashHex}.js`;
            script.onerror = e => {
                if (databaseCallbacks) {
                    databaseCallbacks.err_rn_(hashHex, e);
                }
            };
            document.documentElement.appendChild(script);
        },
        loadDataByNameAndHash: (name, hashHex) => {
            const script = document.createElement("script");
            script.src = `${ROOT_PATH}search.index/${name}/${hashHex}.js`;
            script.onerror = e => {
                if (databaseCallbacks) {
                    databaseCallbacks.err_rd_(hashHex, e);
                }
            };
            document.documentElement.appendChild(script);
        },
    });
} else if (typeof exports !== "undefined") {
    // eslint-disable-next-line no-undef
    exports.initSearch = initSearch;
}