Canonicalize raw type

sdk/lib/_internal/compiler/implementation/elements/elements.dart

Index: sdk/lib/_internal/compiler/implementation/elements/elements.dart
diff --git a/sdk/lib/_internal/compiler/implementation/elements/elements.dart b/sdk/lib/_internal/compiler/implementation/elements/elements.dart
index df07e95ef89fddb49fd694ded8c548b74f16c6fb..b77dd98b1ae6fec89b8a6eafa31804db3ee845ee 100644
--- a/sdk/lib/_internal/compiler/implementation/elements/elements.dart
+++ b/sdk/lib/_internal/compiler/implementation/elements/elements.dart
@@ -838,6 +838,19 @@ class PrefixElement extends Element {
 class TypedefElement extends Element implements TypeDeclarationElement {
   Typedef cachedNode;
   TypedefType cachedType;
+
+  /**
+   * Canonicalize raw version of [cachedType].
+   *
+   * See [ClassElement.rawType] for motivation.
+   *
+   * The [rawType] is computed together with [cachedType] in [computeType].
+   */
+  TypedefType rawType;
+
+  /**
+   * The type annotation which defines this typedef.
+   */
   DartType alias;
 
   bool isResolved = false;
@@ -862,6 +875,16 @@ class TypedefElement extends Element implements TypeDeclarationElement {
     Link<DartType> parameters =
         TypeDeclarationElement.createTypeVariables(this, node.typeParameters);
     cachedType = new TypedefType(this, parameters);
+    if (parameters.isEmpty) {
+      rawType = cachedType;
+    } else {
+      var dynamicParameters = const Link<DartType>();
+      parameters.forEach((_) {
+        dynamicParameters =
+            dynamicParameters.prepend(compiler.types.dynamicType);
+      });
+      rawType = new TypedefType(this, dynamicParameters);
+    }
     compiler.resolveTypedef(this);
     return cachedType;
   }
@@ -1383,7 +1406,36 @@ abstract class TypeDeclarationElement implements Element {
 abstract class ClassElement extends ScopeContainerElement
     implements TypeDeclarationElement {
   final int id;
-  InterfaceType type;
+  /**
+   * The type of [:this:] for this class declaration.
+   *
+   * The type of [:this:] is the interface type based on this element in which
+   * the type arguments are the declared type variables. For instance,
+   * [:List<E>:] for [:List:] and [:Map<K,V>:] for [:Map:].
+   *
+   * This type is computed in [computeType].
+   */
+  InterfaceType thisType;
+
+  /**
+   * The raw type for this class declaration.
+   *
+   * The raw type is the interface type base on this element in which the type
+   * arguments are all [dynamic]. For instance [:List<dynamic>:] for [:List:]
+   * and [:Map<dynamic,dynamic>:] for [:Map:]. For non-generic classes [rawType]
+   * is the same as [thisType].
+   *
+   * The [rawType] field is a canonicalization of the raw type and should be
+   * used to distinguish explicit and implicit uses of the [dynamic]
+   * type arguments. For instance should [:List:] be the [rawType] of the
+   * [:List:] class element whereas [:List<dynamic>:] should be its own
+   * instantiation of [InterfaceType] with [:dynamic:] as type argument. Using
+   * this distinction, we can print the raw type with type arguments only when
+   * the input source has used explicit type arguments.
+   *
+   * This type is computed together with [thisType] in [computeType].
+   */
+  InterfaceType rawType;
   DartType supertype;
   DartType defaultClass;
   Link<DartType> interfaces;
@@ -1409,18 +1461,29 @@ abstract class ClassElement extends ScopeContainerElement
   ClassNode parseNode(Compiler compiler);
 
   InterfaceType computeType(compiler) {
-    if (type == null) {
+    if (thisType == null) {
       if (origin == null) {
         ClassNode node = parseNode(compiler);
         Link<DartType> parameters =
             TypeDeclarationElement.createTypeVariables(this,
                                                        node.typeParameters);
-        type = new InterfaceType(this, parameters);
+        thisType = new InterfaceType(this, parameters);
+        if (parameters.isEmpty) {
+          rawType = thisType;
+        } else {
+          var dynamicParameters = const Link<DartType>();
+          parameters.forEach((_) {
+            dynamicParameters =
+                dynamicParameters.prepend(compiler.types.dynamicType);
+          });
+          rawType = new InterfaceType(this, dynamicParameters);
+        }
       } else {
-        type = origin.computeType(compiler);
+        thisType = origin.computeType(compiler);
+        rawType = origin.rawType;
       }
     }
-    return type;
+    return thisType;
   }
 
   bool get isPatched => patch != null;
@@ -1435,7 +1498,7 @@ abstract class ClassElement extends ScopeContainerElement
   bool isObject(Compiler compiler) =>
       identical(declaration, compiler.objectClass);
 
-  Link<DartType> get typeVariables => type.typeArguments;
+  Link<DartType> get typeVariables => thisType.typeArguments;
 
   ClassElement ensureResolved(Compiler compiler) {
     if (resolutionState == STATE_NOT_STARTED) {
@@ -1729,10 +1792,6 @@ abstract class ClassElement extends ScopeContainerElement
 
   Scope buildScope() => new ClassScope(enclosingElement.buildScope(), this);
 
-  Link<DartType> get allSupertypesAndSelf {
-    return allSupertypes.prepend(new InterfaceType(this));
-  }
-
   String toString() {
     if (origin != null) {
       return 'patch ${super.toString()}';