Add tests

Author: ahejlsberg

tests/baselines/reference/relationComplexityError.errors.txt

@@ -0,0 +1,23 @@
+relationComplexityError.ts(12,5): error TS2322: Type 'T1 & T2' is not assignable to type 'T1 | null'.
+relationComplexityError.ts(12,5): error TS2855: Excessive complexity comparing types 'T1 & T2' and 'T1 | null'.
+
+
+==== relationComplexityError.ts (2 errors) ====
+    // Repro from #55630
+    
+    type Digits = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9';
+    type T1 = `${Digits}${Digits}${Digits}${Digits}` | undefined;
+    type T2 = { a: string } | { b: number };
+    
+    function f1(x: T1, y: T1 & T2) {
+        x = y;
+    }
+    
+    function f2(x: T1 | null, y: T1 & T2) {
+        x = y;  // Complexity error
+        ~
+!!! error TS2322: Type 'T1 & T2' is not assignable to type 'T1 | null'.
+        ~~~~~
+!!! error TS2855: Excessive complexity comparing types 'T1 & T2' and 'T1 | null'.
+    }
+    

tests/baselines/reference/relationComplexityError.symbols

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+//// [tests/cases/compiler/relationComplexityError.ts] ////
+
+=== relationComplexityError.ts ===
+// Repro from #55630
+
+type Digits = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9';
+>Digits : Symbol(Digits, Decl(relationComplexityError.ts, 0, 0))
+
+type T1 = `${Digits}${Digits}${Digits}${Digits}` | undefined;
+>T1 : Symbol(T1, Decl(relationComplexityError.ts, 2, 72))
+>Digits : Symbol(Digits, Decl(relationComplexityError.ts, 0, 0))
+>Digits : Symbol(Digits, Decl(relationComplexityError.ts, 0, 0))
+>Digits : Symbol(Digits, Decl(relationComplexityError.ts, 0, 0))
+>Digits : Symbol(Digits, Decl(relationComplexityError.ts, 0, 0))
+
+type T2 = { a: string } | { b: number };
+>T2 : Symbol(T2, Decl(relationComplexityError.ts, 3, 61))
+>a : Symbol(a, Decl(relationComplexityError.ts, 4, 11))
+>b : Symbol(b, Decl(relationComplexityError.ts, 4, 27))
+
+function f1(x: T1, y: T1 & T2) {
+>f1 : Symbol(f1, Decl(relationComplexityError.ts, 4, 40))
+>x : Symbol(x, Decl(relationComplexityError.ts, 6, 12))
+>T1 : Symbol(T1, Decl(relationComplexityError.ts, 2, 72))
+>y : Symbol(y, Decl(relationComplexityError.ts, 6, 18))
+>T1 : Symbol(T1, Decl(relationComplexityError.ts, 2, 72))
+>T2 : Symbol(T2, Decl(relationComplexityError.ts, 3, 61))
+
+    x = y;
+>x : Symbol(x, Decl(relationComplexityError.ts, 6, 12))
+>y : Symbol(y, Decl(relationComplexityError.ts, 6, 18))
+}
+
+function f2(x: T1 | null, y: T1 & T2) {
+>f2 : Symbol(f2, Decl(relationComplexityError.ts, 8, 1))
+>x : Symbol(x, Decl(relationComplexityError.ts, 10, 12))
+>T1 : Symbol(T1, Decl(relationComplexityError.ts, 2, 72))
+>y : Symbol(y, Decl(relationComplexityError.ts, 10, 25))
+>T1 : Symbol(T1, Decl(relationComplexityError.ts, 2, 72))
+>T2 : Symbol(T2, Decl(relationComplexityError.ts, 3, 61))
+
+    x = y;  // Complexity error
+>x : Symbol(x, Decl(relationComplexityError.ts, 10, 12))
+>y : Symbol(y, Decl(relationComplexityError.ts, 10, 25))
+}
+

tests/baselines/reference/relationComplexityError.types

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+// @strict: true
+// @noEmit: true
+
+// Repro from #55630
+
+type Digits = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9';
+type T1 = `${Digits}${Digits}${Digits}${Digits}` | undefined;
+type T2 = { a: string } | { b: number };
+
+function f1(x: T1, y: T1 & T2) {
+    x = y;
+}
+
+function f2(x: T1 | null, y: T1 & T2) {
+    x = y;  // Complexity error
+}