Preserve type variables in closure conversion.

pkg/kernel/lib/ast.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.
 
 /// -----------------------------------------------------------------------
 ///                           ERROR HANDLING
 /// -----------------------------------------------------------------------
 ///
 /// As a rule of thumb, errors that can be detected statically are handled by
 /// the frontend, typically by translating the erroneous code into a 'throw' or
@@ skipping 3058 matching lines @@
   }
 }
 
 /// Expression of the form `MakeClosure(f, c, t)` where `f` is a name of a
 /// closed top-level function, `c` is a Vector representing closure context, and
 /// `t` is the type of the resulting closure.
 class ClosureCreation extends Expression {
   Reference topLevelFunctionReference;
   Expression contextVector;
   FunctionType functionType;
+  List<DartType> typeArgs;
 
   ClosureCreation(Member topLevelFunction, Expression contextVector,
-      FunctionType functionType)
-      : this.byReference(
-            getMemberReference(topLevelFunction), contextVector, functionType);
+      FunctionType functionType, List<DartType> typeArgs)
+      : this.byReference(getMemberReference(topLevelFunction), contextVector,
+            functionType, typeArgs);
 
-  ClosureCreation.byReference(
-      this.topLevelFunctionReference, this.contextVector, this.functionType) {
+  ClosureCreation.byReference(this.topLevelFunctionReference,
+      this.contextVector, this.functionType, this.typeArgs) {
     contextVector?.parent = this;
   }
 
   Procedure get topLevelFunction => topLevelFunctionReference?.asProcedure;
 
   void set topLevelFunction(Member topLevelFunction) {
     topLevelFunctionReference = getMemberReference(topLevelFunction);
   }
 
   accept(ExpressionVisitor v) => v.visitClosureCreation(this);
   accept1(ExpressionVisitor1 v, arg) => v.visitClosureCreation(this, arg);
 
   visitChildren(Visitor v) {
     contextVector?.accept(v);

[karlklose, 2017/07/25 09:38:23]

I think this method should call visitList(typeArguments) (and also
topLevelFunctionReference.acceptReference(v) and functionType.accept(v)).

[sjindel, 2017/07/25 13:11:48]

I added visitList and functionType ones. But why the acceptReference one? It's
unclear to me where we should visit weak references and where we should not. For
example, the 'PropertyGet' class doesn't visit it's reference to an interface
target.

   }
 
   transformChildren(Transformer v) {
     if (contextVector != null) {
       contextVector = contextVector.accept(v);
       contextVector?.parent = this;
     }
   }
 
   DartType getStaticType(TypeEnvironment types) {
@@ skipping 1556 matching lines @@
   if (typedef_.canonicalName == null) {
     throw '$typedef_ has no canonical name';
   }
   return typedef_.canonicalName;
 }
 
 /// Annotation describing information which is not part of Dart semantics; in
 /// other words, if this information (or any information it refers to) changes,
 /// static analysis and runtime behavior of the library are unaffected.
 const informative = null;