Implement 'instantiate to bounds' feature in resynthesizer.

pkg/analyzer/lib/src/summary/link.dart

 // Copyright (c) 2016, 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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 564 matching lines @@
 
   @override
   List<UnlinkedTypeParam> get _unlinkedTypeParams =>
       _unlinkedClass.typeParameters;
 
   @override
   DartType buildType(
       DartType getTypeArgument(int i), List<int> implicitFunctionTypeIndices) {
     int numTypeParameters = _unlinkedClass.typeParameters.length;
     if (numTypeParameters != 0) {
-      List<DartType> typeArguments = new List<DartType>(numTypeParameters);
-      for (int i = 0; i < numTypeParameters; i++) {
-        typeArguments[i] = getTypeArgument(i);
-      }
-      return new InterfaceTypeImpl.elementWithNameAndArgs(
-          this, name, typeArguments);
+      return new InterfaceTypeImpl.elementWithNameAndArgs(this, name, () {
+        List<DartType> typeArguments = new List<DartType>(numTypeParameters);
+        for (int i = 0; i < numTypeParameters; i++) {
+          typeArguments[i] = getTypeArgument(i);
+        }
+        return typeArguments;
+      });
     } else {
       return _type ??= new InterfaceTypeImpl(this);
     }
   }
 
   @override
   PropertyAccessorElement getGetter(String getterName) {
     for (PropertyAccessorElement accessor in accessors) {
       if (accessor.isGetter && accessor.name == getterName) {
         return accessor;
@@ skipping 1634 matching lines @@
     int numNamed = _getNextInt();
     int numPositional = _getNextInt();
     // TODO(paulberry): don't just pop the args; use their types
     // to infer the type of type arguments.
     stack.length -= numNamed + numPositional;
     strPtr += numNamed;
     EntityRef ref = _getNextRef();
     ConstructorElementForLink element =
         unit._resolveRef(ref.reference).asConstructor;
     if (element != null) {
-      stack.add(element.enclosingClass.buildType(
-          (int i) => i >= ref.typeArguments.length
-              ? DynamicTypeImpl.instance
-              : unit._resolveTypeRef(
-                  ref.typeArguments[i], variable._typeParameterContext),
-          const []));
+      ClassElementForLink_Class enclosingClass = element.enclosingClass;
+      stack.add(enclosingClass.buildType((int i) {
+        TypeParameterElement typeParameter = enclosingClass.typeParameters[i];
+        if (linker.strongMode && typeParameter.bound != null) {

[Paul Berry, 2016/05/09 21:26:36]

I don't think the logic is right here.  Consider the case of:

class C<T extends num> {}
C<int> x;

If I'm reading your code correctly, it looks like it will instantiate x with
type C<num>.

[scheglov, 2016/05/10 02:42:42]

Fixed.

+          return typeParameter.bound;
+        }
+        return i >= ref.typeArguments.length
+            ? DynamicTypeImpl.instance
+            : unit._resolveTypeRef(
+                ref.typeArguments[i], variable._typeParameterContext);
+      }, const []));
     } else {
       stack.add(DynamicTypeImpl.instance);
     }
   }
 
   void _doInvokeMethod() {
     int numNamed = unlinkedConst.ints[intPtr++];
     int numPositional = unlinkedConst.ints[intPtr++];
     List<String> namedArgNames = _getNextStrings(numNamed);
     List<DartType> namedArgTypeList = _popList(numNamed);
@@ skipping 2023 matching lines @@
    * declared earlier in the file.
    */
   final int nestingLevel;
 
   @override
   final TypeParameterizedElementForLink enclosingElement;
 
   TypeParameterTypeImpl _type;
   ElementLocation _location;
 
+  DartType _bound;
+
   TypeParameterElementForLink(
       this.enclosingElement, this._unlinkedTypeParam, this.nestingLevel);
 
   @override
   DartType get bound {
     if (_unlinkedTypeParam.bound == null) {
       return null;
     }
-    // TODO(scheglov) implement
-    throw new UnimplementedError();
+    return _bound ??= enclosingElement.compilationUnit
+        ._resolveTypeRef(_unlinkedTypeParam.bound, enclosingElement);
   }
 
   @override
   String get identifier => name;
 
   @override
   ElementKind get kind => ElementKind.TYPE_PARAMETER;
 
   @override
   ElementLocation get location =>
@@ skipping 423 matching lines @@
    * there are no type parameters in scope.
    */
   TypeParameterizedElementForLink get _typeParameterContext;
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   String toString() => '$enclosingElement.$name';
 }