Make types concrete when checking overrides.

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

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.generated.error_verifier;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 1386 matching lines @@
     if (overridingFT == null || overriddenFT == null) {
       return false;
     }
 
     // Handle generic function type parameters.
     // TODO(jmesserly): this duplicates some code in isSubtypeOf and most of
     // _isGenericFunctionSubtypeOf. Ideally, we'd let TypeSystem produce
     // an error message once it's ready to "return false".
     if (!overridingFT.typeFormals.isEmpty) {
       if (overriddenFT.typeFormals.isEmpty) {
-        overriddenFT = _typeSystem.instantiateToBounds(overriddenFT);
+        overridingFT = _typeSystem.instantiateToBounds(overridingFT);
       } else {
         List<TypeParameterElement> params1 = overridingFT.typeFormals;
         List<TypeParameterElement> params2 = overriddenFT.typeFormals;
         int count = params1.length;
         if (params2.length != count) {
           _errorReporter.reportErrorForNode(
               StaticWarningCode.INVALID_METHOD_OVERRIDE_TYPE_PARAMETERS,
               errorNameTarget, [
             count,
             params2.length,
@@ skipping 3146 matching lines @@
         if ((elt is MethodElement && !elt.isAbstract) ||
             (elt is PropertyAccessorElement && !elt.isAbstract)) {
           // Since we are comparing two function types, we need to do the
           // appropriate type substitutions first ().
           FunctionType foundConcreteFT = _inheritanceManager
               .substituteTypeArgumentsInMemberFromInheritance(
                   concreteType, memberName, enclosingType);
           FunctionType requiredMemberFT = _inheritanceManager
               .substituteTypeArgumentsInMemberFromInheritance(
                   requiredMemberType, memberName, enclosingType);
+          foundConcreteFT =
+              _typeSystem.typeToConcreteType(_typeProvider, foundConcreteFT);
+          requiredMemberFT =
+              _typeSystem.typeToConcreteType(_typeProvider, requiredMemberFT);
           if (_typeSystem.isSubtypeOf(foundConcreteFT, requiredMemberFT)) {
             continue;
           }
         }
       }
       // The not qualifying concrete executable element was found, add it to the
       // list.
       missingOverrides.add(executableElt);
     }
     // Now that we have the set of missing overrides, generate a warning on this
@@ skipping 1554 matching lines @@
 class _InvocationCollector extends RecursiveAstVisitor {
   final List<String> superCalls = <String>[];
 
   @override
   visitMethodInvocation(MethodInvocation node) {
     if (node.target is SuperExpression) {
       superCalls.add(node.methodName.name);
     }
   }
 }