fix #25578, implement @covariant parameter overrides

pkg/analyzer/lib/src/generated/element_resolver.dart

Index: pkg/analyzer/lib/src/generated/element_resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/element_resolver.dart b/pkg/analyzer/lib/src/generated/element_resolver.dart
index e70c1d8e639a6922a1efee1bf95e9b8bbdc1a0b2..5fb43b62b12accfdc134a740b58dc7f6a6df8c1a 100644
--- a/pkg/analyzer/lib/src/generated/element_resolver.dart
+++ b/pkg/analyzer/lib/src/generated/element_resolver.dart
@@ -419,7 +419,7 @@ class ElementResolver extends SimpleAstVisitor<Object> {
 
   @override
   Object visitFieldFormalParameter(FieldFormalParameter node) {
-    _resolveMetadataForParameter(node.element, node);
+    _resolveMetadataForParameter(node);
     return super.visitFieldFormalParameter(node);
   }
 
@@ -463,7 +463,7 @@ class ElementResolver extends SimpleAstVisitor<Object> {
 
   @override
   Object visitFunctionTypedFormalParameter(FunctionTypedFormalParameter node) {
-    _resolveMetadataForParameter(node.element, node);
+    _resolveMetadataForParameter(node);
     return null;
   }
 
@@ -1055,7 +1055,7 @@ class ElementResolver extends SimpleAstVisitor<Object> {
 
   @override
   Object visitSimpleFormalParameter(SimpleFormalParameter node) {
-    _resolveMetadataForParameter(node.element, node);
+    _resolveMetadataForParameter(node);
     return null;
   }
 
@@ -2270,8 +2270,7 @@ class ElementResolver extends SimpleAstVisitor<Object> {
    * Given a [node] that can have annotations associated with it, resolve the
    * annotations in the element model representing annotations to the node.
    */
-  void _resolveMetadataForParameter(
-      Element element, NormalFormalParameter node) {
+  void _resolveMetadataForParameter(NormalFormalParameter node) {
     _resolveAnnotations(node.metadata);
   }