Add support for converted closures with explicit contexts to VM

pkg/kernel/lib/transformations/closure/converter.dart

Index: pkg/kernel/lib/transformations/closure/converter.dart
diff --git a/pkg/kernel/lib/transformations/closure/converter.dart b/pkg/kernel/lib/transformations/closure/converter.dart
index e1865f7fd6d90a6c04a8e0dbeba37456490f612f..d03da68508882601d79cab1f09f254952c9ce674 100644
--- a/pkg/kernel/lib/transformations/closure/converter.dart
+++ b/pkg/kernel/lib/transformations/closure/converter.dart
@@ -230,6 +230,7 @@ class ClosureConverter extends Transformer {
       }
     }
     rewriter = null;
+    context = null;
     // Transform constructor body.
     FunctionNode function = node.function;
     if (function.body != null && function.body is! EmptyStatement) {
@@ -424,6 +425,8 @@ class ClosureConverter extends Transformer {
 
     FunctionNode function = node.function;
     if (function.body != null) {
+      bool hadSingleStatementBody = function.body is! Block;

[karlklose, 2017/06/19 11:58:14]

Please check if this is still required.

[Dmitry Stefantsov, 2017/06/19 12:12:44]

Thanks for pointing to this!  Apparently, DillLibraryBuilder code doesn't have
this requirement any more.  So I removed this line and the body-restoration code
in lines 437-452 below.

+
       setupContextForFunctionBody(function);
       VariableDeclaration self = thisAccess[currentMemberFunction];
       if (self != null) {
@@ -431,6 +434,22 @@ class ClosureConverter extends Transformer {
       }
       node.transformChildren(this);
       resetContext();
+
+      // Here a special case is handled: the body of the procedure was a single
+      // statement and after the transformation it is a block with a single
+      // statement inside.  In this case we make this statement the body of the
+      // procedure again.  It is required to follow the conventions imposed by
+      // [addClass] in [DillLibraryBuilder].
+      // See [dill_library_builder.dart]
+      // (../../../../front_end/lib/src/fasta/dill/dill_library_builder.dart)
+      // for details.
+      if (hadSingleStatementBody && function.body is Block) {
+        Block body = function.body;
+        if (body.statements.length == 1) {
+          function.body = body.statements[0];
+          function.body.parent = function;
+        }
+      }
     }
 
     return node;
@@ -483,7 +502,7 @@ class ClosureConverter extends Transformer {
   TreeNode visitBlock(Block node) {
     return saveContext(() {
       BlockRewriter blockRewriter = rewriter = rewriter.forNestedBlock(node);
-      blockRewriter.transformStatements(node, this);
+      blockRewriter.transformStatements(this);
       return node;
     });
   }
@@ -627,25 +646,26 @@ class ClosureConverter extends Transformer {
   }
 
   TreeNode visitStaticGet(StaticGet node) {
-    Member target = node.target;
-    if (target is Procedure && target.kind == ProcedureKind.Method) {
-      VariableDeclaration contextVariable = new VariableDeclaration(
-          "#contextParameter",
-          type: const VectorType());
-      Expression expression = getTearOffExpression(
-          null, node.target, contextVariable, new NullLiteral());
-      expression.transformChildren(this);
-      return expression;
-    }
+    // TODO(dmitryas): Add support for tear-offs. When added, uncomment this.
+    //
+    // Member target = node.target;
+    // if (target is Procedure && target.kind == ProcedureKind.Method) {
+    //   VariableDeclaration contextVariable = new VariableDeclaration(
+    //       "#contextParameter",
+    //       type: const VectorType());
+    //   Expression expression = getTearOffExpression(
+    //       null, node.target, contextVariable, new NullLiteral());
+    //   expression.transformChildren(this);
+    //   return expression;
+    // }
     return super.visitStaticGet(node);
   }
 
   TreeNode visitPropertyGet(PropertyGet node) {
     Name tearOffName = tearOffGetterNames[node.name];
     if (tearOffName != null) {
-      MethodInvocation replacement = new MethodInvocation(
-          node.receiver, tearOffName, new Arguments(<Expression>[]));
-      return super.visitMethodInvocation(replacement);
+      PropertyGet replacement = new PropertyGet(node.receiver, tearOffName);
+      return super.visitPropertyGet(replacement);
     }
     return super.visitPropertyGet(node);
   }
@@ -871,7 +891,7 @@ class ClosureConverter extends Transformer {
             self, procedure, contextVariable, parent.expression)));
 
         Procedure tearOffMethod = new Procedure(
-            name, ProcedureKind.Method, tearOffMethodFunction,
+            name, ProcedureKind.Getter, tearOffMethodFunction,
             fileUri: currentFileUri);
         newClassMembers.add(tearOffMethod);