Check bounds of type parameters of function type aliases.

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 5207 matching lines @@
    */
   void _checkForTypeArgumentNotMatchingBounds(TypeName typeName) {
     if (typeName.typeArguments == null) {
       return;
     }
     // prepare Type
     DartType type = typeName.type;
     if (type == null) {
       return;
     }
-    // prepare ClassElement
+    // prepare type parameters
+    List<DartType> typeParameters = null;
+    List<TypeParameterElement> boundingElts = null;
+    List<DartType> typeArguments = null;
     Element element = type.element;
     if (element is ClassElement) {

[Brian Wilkerson, 2016/05/10 17:09:28]

Both ClassElement and FunctionTypeAliasElement are subtypes of
TypeParameterizedElement, and both InterfaceType and FunctionType are subtypes
of ParameterizedType. It would be nice if we could use that fact to remove the
duplication.

-      // prepare type parameters
-      List<DartType> typeParameters = element.type.typeArguments;
-      List<TypeParameterElement> boundingElts = element.typeParameters;
-      // iterate over each bounded type parameter and corresponding argument
-      NodeList<TypeName> typeNameArgList = typeName.typeArguments.arguments;
-      List<DartType> typeArguments = (type as InterfaceType).typeArguments;
-      int loopThroughIndex =
-          math.min(typeNameArgList.length, boundingElts.length);
-
-      bool shouldSubstitute = typeArguments.length != 0 &&
-          typeArguments.length == typeParameters.length;
-      for (int i = 0; i < loopThroughIndex; i++) {
-        TypeName argTypeName = typeNameArgList[i];
-        DartType argType = argTypeName.type;
-        DartType boundType = boundingElts[i].bound;
-        if (argType != null && boundType != null) {
-          if (shouldSubstitute) {
-            boundType = boundType.substitute2(typeArguments, typeParameters);
+      typeParameters = element.type.typeArguments;
+      boundingElts = element.typeParameters;
+      typeArguments = (type as InterfaceType).typeArguments;
+    } else if (element is FunctionTypeAliasElement) {
+      typeParameters = element.type.typeArguments;
+      boundingElts = element.typeParameters;
+      typeArguments = (type as FunctionType).typeArguments;
+    } else {
+      return;
+    }
+    // iterate over each bounded type parameter and corresponding argument
+    NodeList<TypeName> typeNameArgList = typeName.typeArguments.arguments;
+    int loopThroughIndex =
+        math.min(typeNameArgList.length, boundingElts.length);
+    bool shouldSubstitute = typeArguments.length != 0 &&
+        typeArguments.length == typeParameters.length;
+    for (int i = 0; i < loopThroughIndex; i++) {
+      TypeName argTypeName = typeNameArgList[i];
+      DartType argType = argTypeName.type;
+      DartType boundType = boundingElts[i].bound;
+      if (argType != null && boundType != null) {
+        if (shouldSubstitute) {
+          boundType = boundType.substitute2(typeArguments, typeParameters);
+        }
+        if (!_typeSystem.isSubtypeOf(argType, boundType)) {
+          ErrorCode errorCode;
+          if (_isInConstInstanceCreation) {
+            errorCode = CompileTimeErrorCode.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS;
+          } else {
+            errorCode = StaticTypeWarningCode.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS;
           }
-          if (!_typeSystem.isSubtypeOf(argType, boundType)) {
-            ErrorCode errorCode;
-            if (_isInConstInstanceCreation) {
-              errorCode =
-                  CompileTimeErrorCode.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS;
-            } else {
-              errorCode =
-                  StaticTypeWarningCode.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS;
-            }
-            _errorReporter.reportTypeErrorForNode(
-                errorCode, argTypeName, [argType, boundType]);
-          }
+          _errorReporter.reportTypeErrorForNode(
+              errorCode, argTypeName, [argType, boundType]);
         }
       }
     }
   }
 
   /**
    * Check whether the given type [name] is a type parameter being used to
    * define a static member.
    *
    * See [StaticWarningCode.TYPE_PARAMETER_REFERENCED_BY_STATIC].
@@ skipping 963 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);
     }
   }
 }