[wildcards] fix super formal parameter handling

Fixes:

language/wildcard_variables/initializing_formal_parameters/super_test
co19/LanguageFeatures/Wildcards/super_parameters_A04_t01

See: #55680

Change-Id: I7223da0df0f66fcc7b5737af686e34aa387c5c92
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/379721
Commit-Queue: Phil Quitslund <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: pq

pkg/analyzer/lib/src/error/duplicate_definition_verifier.dart

@@ -69,6 +69,14 @@ class DuplicateDefinitionVerifier {
       if (identifier != null) {
         // The identifier can be null if this is a parameter list for a generic
         // function type.
+
+        // Skip wildcard `super._`.
+        if (parameter is SuperFormalParameter &&
+            identifier.lexeme == '_' &&
+            _currentLibrary.hasWildcardVariablesFeatureEnabled) {
+          continue;
+        }
+
         _checkDuplicateIdentifier(definedNames, identifier,
             element: parameter.declaredElement!);
       }

pkg/analyzer/test/src/diagnostics/duplicate_definition_test.dart

@@ -2658,8 +2658,6 @@ class B extends A {
 }
 ''', [
       error(WarningCode.UNUSED_FIELD, 17, 1),
-      error(CompileTimeErrorCode.DUPLICATE_DEFINITION, 74, 1,
-          contextMessages: [message(testFile, 65, 1)]),
     ]);
   }