fix(typescript): allow generic params and arrow params with same name

docs/CHANGELOG.md

@@ -46,6 +46,9 @@ Semantic Versioning.
 * TypeScript support (still experimental):
   * A newline after `public`, `protected`, `private`, or `readonly` inside a
     class is now interpreted correctly.
+  * `<T>(T: T) => {}` (a generic arrow function with the same name for a
+    run-time parameter and a generic parameter) no longer falsely reports
+    [E0034][] ("redeclaration of variable").
   * Nested `module` declarations no longer falsely report [E0361][]. E0361's
     message has been changed:
     * Before: "module with string name is only allowed at the top level"

src/quick-lint-js/fe/variable-analyzer.cpp

@@ -1049,7 +1049,6 @@ void Variable_Analyzer::report_error_if_variable_declaration_conflicts(
       (kind == VK::_function           && other_kind == VK::_function) ||
       (kind == VK::_function           && other_kind == VK::_var) ||
       (kind == VK::_function           && other_kind_is_parameter) ||
-      (kind == VK::_function_parameter && other_kind == VK::_generic_parameter) ||
       (kind == VK::_import             && other_kind == VK::_interface) ||
       (kind == VK::_interface          && other_kind == VK::_class) ||
       (kind == VK::_interface          && other_kind == VK::_import) ||
@@ -1074,6 +1073,7 @@ void Variable_Analyzer::report_error_if_variable_declaration_conflicts(
       (kind == VK::_var                && other_kind == VK::_var) ||
       (kind == VK::_var                && other_kind_is_parameter) ||
       (kind_is_parameter               && other_kind == VK::_function) ||
+      (kind_is_parameter               && other_kind == VK::_generic_parameter) ||
       (kind_is_parameter               && other_kind_is_parameter) ||
       (!is_type(kind)                  && other_kind == VK::_interface) ||
       // clang-format on

test/test-variable-analyzer-multiple-declarations.cpp

@@ -121,6 +121,8 @@ TEST(Test_Variable_Analyzer_Multiple_Declarations,
      function_parameter_can_have_same_name_as_generic_parameter) {
   test_parse_and_analyze(u8"(function <T>(T) {});"_sv, no_diags,
                          typescript_analyze_options, default_globals);
+  test_parse_and_analyze(u8"(<T>(T) => {});"_sv, no_diags,
+                         typescript_analyze_options, default_globals);
 }
 }
 }