Detect SIM910 when using variadic keyword arguments, i.e., **kwargs (#13503)

Closes #13493

Author: zanieb

crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM910.py

@@ -33,3 +33,19 @@
 # OK
 ages = ["Tom", "Maria", "Dog"]
 age = ages.get("Cat", None)
+
+# SIM910
+def foo(**kwargs):
+    a = kwargs.get('a', None)
+
+# SIM910
+def foo(some_dict: dict):
+    a = some_dict.get('a', None)
+
+# OK
+def foo(some_other: object):
+    a = some_other.get('a', None)
+
+# OK
+def foo(some_other):
+    a = some_other.get('a', None)

crates/ruff_linter/src/rules/flake8_simplify/snapshots/ruff_linter__rules__flake8_simplify__tests__SIM910_SIM910.py.snap

@@ -119,4 +119,44 @@ SIM910.py:31:7: SIM910 [*] Use `ages.get("Cat")` instead of `ages.get("Cat", Non
 33 33 | # OK
 34 34 | ages = ["Tom", "Maria", "Dog"]
 
+SIM910.py:39:9: SIM910 [*] Use `kwargs.get('a')` instead of `kwargs.get('a', None)`
+   |
+37 | # SIM910
+38 | def foo(**kwargs):
+39 |     a = kwargs.get('a', None)
+   |         ^^^^^^^^^^^^^^^^^^^^^ SIM910
+40 | 
+41 | # SIM910
+   |
+   = help: Replace `kwargs.get('a', None)` with `kwargs.get('a')`
+
+ℹ Safe fix
+36 36 | 
+37 37 | # SIM910
+38 38 | def foo(**kwargs):
+39    |-    a = kwargs.get('a', None)
+   39 |+    a = kwargs.get('a')
+40 40 | 
+41 41 | # SIM910
+42 42 | def foo(some_dict: dict):
 
+SIM910.py:43:9: SIM910 [*] Use `some_dict.get('a')` instead of `some_dict.get('a', None)`
+   |
+41 | # SIM910
+42 | def foo(some_dict: dict):
+43 |     a = some_dict.get('a', None)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^ SIM910
+44 | 
+45 | # OK
+   |
+   = help: Replace `some_dict.get('a', None)` with `some_dict.get('a')`
+
+ℹ Safe fix
+40 40 | 
+41 41 | # SIM910
+42 42 | def foo(some_dict: dict):
+43    |-    a = some_dict.get('a', None)
+   43 |+    a = some_dict.get('a')
+44 44 | 
+45 45 | # OK
+46 46 | def foo(some_other: object):

crates/ruff_python_semantic/src/analyze/typing.rs

@@ -738,9 +738,26 @@ pub fn is_list(binding: &Binding, semantic: &SemanticModel) -> bool {
 
 /// Test whether the given binding can be considered a dictionary.
 ///
-/// For this, we check what value might be associated with it through it's initialization and
-/// what annotation it has (we consider `dict` and `typing.Dict`).
+/// For this, we check what value might be associated with it through it's initialization,
+/// what annotation it has (we consider `dict` and `typing.Dict`), and if it is a variadic keyword
+/// argument parameter.
 pub fn is_dict(binding: &Binding, semantic: &SemanticModel) -> bool {
+    // ```python
+    // def foo(**kwargs):
+    //   ...
+    // ```
+    if matches!(binding.kind, BindingKind::Argument) {
+        if let Some(Stmt::FunctionDef(ast::StmtFunctionDef { parameters, .. })) =
+            binding.statement(semantic)
+        {
+            if let Some(kwarg_parameter) = parameters.kwarg.as_deref() {
+                if kwarg_parameter.name.range() == binding.range() {
+                    return true;
+                }
+            }
+        }
+    }
+
     check_type::<DictChecker>(binding, semantic)
 }