Issue 5302. Type alias type parameters should not conflict with formal parameters

compiler/java/com/google/dart/compiler/resolver/Resolver.java

 // Copyright (c) 2012, 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.
 
 package com.google.dart.compiler.resolver;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.dart.compiler.DartCompilationPhase;
@@ skipping 226 matching lines @@
       }
       return null;
     }
 
     @Override
     public Element visitFunctionTypeAlias(DartFunctionTypeAlias alias) {
       alias.getMetadata().accept(this);
       getContext().pushFunctionAliasScope(alias);
       resolveFunctionAlias(alias);
 
-      List<DartParameter> parameters = alias.getParameters();
-      for (DartParameter parameter : parameters) {
-        assert parameter.getElement() != null;
-        if (parameter.getQualifier() instanceof DartThisExpression) {
-          onError(parameter.getName(), ResolverErrorCode.PARAMETER_INIT_OUTSIDE_CONSTRUCTOR);
-        } else {
-          if (parameter.getModifiers().isNamed()
-              && DartIdentifier.isPrivateName(parameter.getElement().getName())) {
-            onError(parameter.getName(),
-                ResolverErrorCode.NAMED_PARAMETERS_CANNOT_START_WITH_UNDER);
+      getContext().pushScope("<parameters>");
+      try {
+        List<DartParameter> parameters = alias.getParameters();
+        for (DartParameter parameter : parameters) {
+          assert parameter.getElement() != null;
+          if (parameter.getQualifier() instanceof DartThisExpression) {
+            onError(parameter.getName(), ResolverErrorCode.PARAMETER_INIT_OUTSIDE_CONSTRUCTOR);
+          } else {
+            if (parameter.getModifiers().isNamed()
+                && DartIdentifier.isPrivateName(parameter.getElement().getName())) {
+              onError(parameter.getName(),
+                  ResolverErrorCode.NAMED_PARAMETERS_CANNOT_START_WITH_UNDER);
+            }
+            getContext().declare(parameter.getElement(), ResolverErrorCode.DUPLICATE_PARAMETER);
           }
-          getContext().declare(
-              parameter.getElement(),
-              ResolverErrorCode.DUPLICATE_PARAMETER);
         }
+      } finally {
+        getContext().popScope();
       }
 
       getContext().popScope();
       return null;
     }
 
     @Override
     public Element visitClass(DartClass cls) {
       assert currentMethod == null : "nested class?";
       ClassNodeElement classElement = cls.getElement();
@@ skipping 2105 matching lines @@
           ClassElement currentClass = (ClassElement) constructor.getEnclosingElement();
           if (nextClass == currentClass) {
             return (ConstructorNodeElement) nextConstructorElement;
           }
         }
       }
     }
     return null;
   }
 }