Add ability to look up type parameters that are associated with ClassEntities with the element envi…

pkg/compiler/lib/src/kernel/element_map_impl.dart

 // Copyright (c) 2017, 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 dart2js.kernel.element_map;
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart' show BoxLocal, ThisLocal;
 import '../common.dart';
@@ skipping 235 matching lines @@
                   _getTypeVariable(node.typeParameters[index]));
             }));
         data.rawType = new InterfaceType(
             cls,
             new List<DartType>.filled(
                 node.typeParameters.length, const DynamicType()));
       }
     }
   }
 
+  List<DartType> getTypeVariables(ir.Class cls) {
+    return cls.typeParameters
+        .map((ir.TypeParameter type) => getDartType(type.bound));

[Johnni Winther, 2017/09/04 06:59:56]

This is not the correct implementation.

class C<T extends String> {}

for this class [getTypeVariables] would return `[String]` and not `[T]`.

The correct implementation can be implementated directly in the element
environment (see comment below).

[Emily Fortuna, 2017/09/05 17:13:31]

Done.

+  }
+
   TypeVariableEntity getTypeVariable(ir.TypeParameter node) =>
       _getTypeVariable(node);
 
   TypeVariableEntity _getTypeVariable(ir.TypeParameter node);
 
   void _ensureSupertypes(ClassEntity cls, ClassData data) {
     assert(checkFamily(cls));
     if (data.orderedTypeSet == null) {
       _ensureThisAndRawType(cls, data);
 
@@ skipping 1001 matching lines @@
   @override
   FunctionType getFunctionType(FunctionEntity function) {
     return elementMap._getFunctionType(function);
   }
 
   @override
   DartType getFieldType(FieldEntity field) {
     return elementMap._getFieldType(field);
   }
 
+  List<DartType> getTypeVariables(ClassEntity cls) {
+    ir.Class irClass = elementMap._classes.getEnv(cls).cls;
+    // Not all entities have corresponding ir.Nodes, but those that do not are
+    // synthetic elements like closure classes, which don't have specialized
+    // type variables.
+    return irClass == null
+        ? const <DartType>[]
+        : elementMap.getTypeVariables(irClass);

[Johnni Winther, 2017/09/04 06:59:56]

This method can be implemented using the current interface:

List<DartType> getTypeVariables(ClassEntity cls) =>
    getThisType(cls).typeArguments;

[Emily Fortuna, 2017/09/05 17:13:31]

Done.

+  }
+
   @override
   FunctionType getLocalFunctionType(covariant KLocalFunction function) {
     return function.functionType;
   }
 
   @override
   ConstantExpression getFieldConstant(FieldEntity field) {
     return elementMap._getFieldConstantExpression(field);
   }
 
@@ skipping 1055 matching lines @@
   ///
   /// These names are not used in generated code, just as element name.
   String _getClosureVariableName(String name, int id) {
     return "_captured_${name}_$id";
   }
 
   String getDeferredUri(ir.LibraryDependency node) {
     throw new UnimplementedError('JsKernelToElementMap.getDeferredUri');
   }
 }