[analyzer] copy generic type args when inferring a new function type for an ExecutableElement

pkg/analyzer/test/src/task/strong_mode_test.dart

 // Copyright (c) 2015, 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 test.src.task.strong_mode_test;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/strong_mode.dart';
@@ skipping 689 matching lines @@
     String methodName = 'm';
     CompilationUnitElement unit = resolve('''
 class A<E> {
   $methodName(E p) => 0;
 }
 class C<E> implements A<E> {
   $methodName(p) => 0;
 }
 ''');
     ClassElement classC = unit.getType('C');
+    DartType typeCE = classC.typeParameters[0].type;
     MethodElement methodC = classC.getMethod(methodName);
     ParameterElement parameterC = methodC.parameters[0];
     expect(parameterC.type.isDynamic, isTrue);
+    expect(methodC.type.typeArguments, [typeCE]);
 
     inferrer.inferCompilationUnit(unit);
 
     expect(parameterC.type, classC.typeParameters[0].type);
+    expect(methodC.type.typeArguments, [typeCE],

[Jennifer Messerly, 2015/09/24 22:35:56]

this check was failing without the fix.

+        reason: 'function type should still have type arguments');
   }
 
   void test_inferCompilationUnit_method_return_multiple_different() {
     InstanceMemberInferrer inferrer = createInferrer;
     String methodName = 'm';
     CompilationUnitElement unit = resolve('''
 class A {
   int $methodName() => 0;
 }
 class B {
@@ skipping 183 matching lines @@
     String methodName = 'm';
     CompilationUnitElement unit = resolve('''
 class A<E> {
   E $methodName() => 0;
 }
 class B<E> extends A<E> {
   $methodName() => 0;
 }
 ''');
     ClassElement classB = unit.getType('B');
+    DartType typeBE = classB.typeParameters[0].type;
     MethodElement methodB = classB.getMethod(methodName);
     expect(methodB.returnType.isDynamic, isTrue);
+    expect(methodB.type.typeArguments, [typeBE]);
 
     inferrer.inferCompilationUnit(unit);
 
     expect(methodB.returnType, classB.typeParameters[0].type);
+    expect(methodB.type.typeArguments, [typeBE],
+        reason: 'function type should still have type arguments');
   }
 }
 
 @reflectiveTest
 class VariableGathererTest extends AbstractContextTest {
   void test_creation_withFilter() {
     VariableFilter filter = (variable) => true;
     VariableGatherer gatherer = new VariableGatherer(filter);
     expect(gatherer, isNotNull);
     expect(gatherer.filter, filter);
@@ skipping 51 matching lines @@
     }
   }
 }
 ''');
     CompilationUnit unit = context.resolveCompilationUnit2(source, source);
     VariableGatherer gatherer = new VariableGatherer(filter);
     unit.accept(gatherer);
     return gatherer.results;
   }
 }