Produce run-time error when type parameters are accessed from static context.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

 // 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.
 
 part of resolution;
 
 abstract class TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   DartType getType(Node node);
@@ skipping 1020 matching lines @@
     breakTargetStack = breakTargetStack.tail;
     labels = labels.outer;
   }
 }
 
 class TypeResolver {
   final Compiler compiler;
 
   TypeResolver(this.compiler);
 
+  bool anyMalformedTypesInThere(Link<DartType> list) {
+    for (Link<DartType> link = list;
+        !link.isEmpty;
+        link = link.tail) {
+      DartType dtype = link.head;
+      if (dtype is MalformedType) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   Element resolveTypeName(Scope scope, TypeAnnotation node) {
     Identifier typeName = node.typeName.asIdentifier();
     Send send = node.typeName.asSend();
     return resolveTypeNameInternal(scope, typeName, send);
   }
 
   Element resolveTypeNameInternal(Scope scope, Identifier typeName, Send send) {
     if (send != null) {
       typeName = send.selector;
     }
@@ skipping 23 matching lines @@
     }
   }
 
   // TODO(johnniwinther): Change  [onFailure] and [whenResolved] to use boolean
   // flags instead of closures.
   // TODO(johnniwinther): Should never return [null] but instead an erroneous
   // type.
   DartType resolveTypeAnnotation(
       TypeAnnotation node,
       Scope scope,
+      bool inStaticContext,
       {onFailure(Node node, MessageKind kind, [List arguments]),
        whenResolved(Node node, DartType type)}) {
     if (onFailure == null) {
       onFailure = (n, k, [arguments]) {};
     }
     if (whenResolved == null) {
       whenResolved = (n, t) {};
     }
     if (scope == null) {
       compiler.internalError('resolveTypeAnnotation: no scope specified');
     }
-    return resolveTypeAnnotationInContext(scope, node, onFailure,
-                                          whenResolved);
+    return resolveTypeAnnotationInContext(scope, node, inStaticContext,
+        onFailure, whenResolved);
   }
 
   DartType resolveTypeAnnotationInContext(Scope scope, TypeAnnotation node,
+                                          bool inStaticContext,
                                           onFailure, whenResolved) {
     Element element = resolveTypeName(scope, node);
     DartType type;
     if (element == null) {
       onFailure(node, MessageKind.CANNOT_RESOLVE_TYPE, [node.typeName]);
     } else if (element.isAmbiguous()) {
       AmbiguousElement ambiguous = element;
       onFailure(node, ambiguous.messageKind, ambiguous.messageArguments);
     } else if (!element.impliesType()) {
       onFailure(node, MessageKind.NOT_A_TYPE, [node.typeName]);
     } else {
       if (identical(element, compiler.types.voidType.element) ||
           identical(element, compiler.types.dynamicType.element)) {
         type = element.computeType(compiler);
       } else if (element.isClass()) {
         ClassElement cls = element;
         cls.ensureResolved(compiler);
         Link<DartType> arguments =
-            resolveTypeArguments(node, cls.typeVariables, scope,
+            resolveTypeArguments(node, cls.typeVariables,
+                                 inStaticContext, scope,
                                  onFailure, whenResolved);
         if (cls.typeVariables.isEmpty && arguments.isEmpty) {
           // Use the canonical type if it has no type parameters.
           type = cls.computeType(compiler);
         } else {
-          type = new InterfaceType(cls.declaration, arguments);
+          // In checked mode malformed-ness of the type argument bubbles up.
+          if (anyMalformedTypesInThere(arguments) &&
+              compiler.enableTypeAssertions) {
+            type = new MalformedType(
+                new MalformedTypeElement(node, element));
+          } else {
+            type = new InterfaceType(cls.declaration, arguments);
+          }
         }
       } else if (element.isTypedef()) {
         TypedefElement typdef = element;
         // TODO(ahe): Should be [ensureResolved].
         compiler.resolveTypedef(typdef);
         typdef.computeType(compiler);
         Link<DartType> arguments = resolveTypeArguments(
-            node, typdef.typeVariables,
+            node, typdef.typeVariables, inStaticContext,
             scope, onFailure, whenResolved);
         if (typdef.typeVariables.isEmpty && arguments.isEmpty) {
           // Return the canonical type if it has no type parameters.
           type = typdef.computeType(compiler);
         } else {
           type = new TypedefType(typdef, arguments);
         }
       } else if (element.isTypeVariable()) {
-        type = element.computeType(compiler);
+        if (inStaticContext) {
+          compiler.reportWarning(node,
+              MessageKind.TYPE_VARIABLE_WITHIN_STATIC_MEMBER.message(
+                  [element]));
+          type = new MalformedType(new MalformedTypeElement(node, element));
+        } else {
+          type = element.computeType(compiler);
+        }
       } else {
         compiler.cancel("unexpected element kind ${element.kind}",
                         node: node);
       }
     }
     whenResolved(node, type);
     return type;
   }
 
   Link<DartType> resolveTypeArguments(TypeAnnotation node,
                                       Link<DartType> typeVariables,
+                                      bool inStaticContext,
                                       Scope scope, onFailure, whenResolved) {
     if (node.typeArguments == null) {
       return const Link<DartType>();
     }
     var arguments = new LinkBuilder<DartType>();
     for (Link<Node> typeArguments = node.typeArguments.nodes;
          !typeArguments.isEmpty;
          typeArguments = typeArguments.tail) {
       if (typeVariables.isEmpty) {
         onFailure(typeArguments.head, MessageKind.ADDITIONAL_TYPE_ARGUMENT);
       }
       DartType argType = resolveTypeAnnotationInContext(scope,
                                                     typeArguments.head,
+                                                    inStaticContext,
                                                     onFailure,
                                                     whenResolved);
+      // In production mode malformed type argument is replaced with dynamic.
+      if (argType is MalformedType && !compiler.enableTypeAssertions) {
+        argType = compiler.types.dynamicType;

[ahe, 2012/11/23 06:16:13]

I would rather do this check in the backend.  Here is why: we try to keep the
resolution phase as close to the truth as possible.  In this case, the type
really is malformed, and if you were building, for example, an IDE based on
dart2js, it would be nice to have the details (that is the malformed type)
rather than the dynamic type.

[aam-me, 2012/11/23 14:02:28]

Okay, understand.
Started looking for a good place in the backend for this replacement logic, but
discovered that it is not needed at all.

+      }
       arguments.addLast(argType);
       if (!typeVariables.isEmpty) {
         typeVariables = typeVariables.tail;
       }
     }
     if (!typeVariables.isEmpty) {
       onFailure(node.typeArguments, MessageKind.MISSING_TYPE_ARGUMENT);
     }
     return arguments.toLink();
   }
@@ skipping 872 matching lines @@
           argument.element.enclosingElement);
     } else if (argument is InterfaceType) {
       InterfaceType type = argument;
       type.arguments.forEach((DartType argument) {
         analyzeTypeArgument(type, argument);
       });
     }
   }
 
   DartType resolveTypeAnnotation(TypeAnnotation node) {
-    // TODO(johnniwinther): Remove this together with the named arguments
-    // on [TypeResolver.resolveTypeAnnotation].
-    void checkAndUseType(TypeAnnotation annotation, DartType type) {
-      useType(annotation, type);
-      if (type != null &&
-          identical(type.kind, TypeKind.TYPE_VARIABLE) &&
-          enclosingElement.isInStaticMember()) {
-        warning(annotation, MessageKind.TYPE_VARIABLE_WITHIN_STATIC_MEMBER,
-                [type]);
-      }
-    }
-
     Function report = typeRequired ? error : warning;
     DartType type = typeResolver.resolveTypeAnnotation(
-        node, scope, onFailure: report, whenResolved: checkAndUseType);
+        node, scope, enclosingElement.isInStaticMember(),
+        onFailure: report, whenResolved: useType);
     if (type == null) return null;
     if (inCheckContext) {
       compiler.enqueuer.resolution.registerIsCheck(type);
     }
     if (typeRequired || inCheckContext) {
       if (type is InterfaceType) {
         InterfaceType itf = type;
         itf.arguments.forEach((DartType argument) {
           analyzeTypeArgument(type, argument);
         });
@@ skipping 346 matching lines @@
       SourceString typeName = typeVariable.name;
       TypeVariable typeNode = nodeLink.head;
       if (nameSet.contains(typeName)) {
         error(typeNode, MessageKind.DUPLICATE_TYPE_VARIABLE_NAME, [typeName]);
       }
       nameSet.add(typeName);
 
       TypeVariableElement variableElement = typeVariable.element;
       if (typeNode.bound != null) {
         DartType boundType = typeResolver.resolveTypeAnnotation(
-            typeNode.bound, scope, onFailure: warning);
+            typeNode.bound, scope, element.isInStaticMember(),
+            onFailure: warning);
         if (boundType != null && boundType.element == variableElement) {
           // TODO(johnniwinther): Check for more general cycles, like
           // [: <A extends B, B extends C, C extends B> :].
           warning(node, MessageKind.CYCLIC_TYPE_VARIABLE,
                   [variableElement.name]);
         } else if (boundType != null) {
           variableElement.bound = boundType;
         } else {
           // TODO(johnniwinther): Should be an erroneous type.
           variableElement.bound = compiler.objectClass.computeType(compiler);
@@ skipping 667 matching lines @@
     return e;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitReturn(Return node) {
     Node expression = node.expression;
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }