[es7] implement |do| expressions proposal

src/typing.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/typing.h"
 
 #include "src/frames.h"
 #include "src/frames-inl.h"
 #include "src/ostreams.h"
 #include "src/parser.h"  // for CompileTimeValue; TODO(rossberg): should move
@@ skipping 331 matching lines @@
 void AstTyper::VisitFunctionLiteral(FunctionLiteral* expr) {}
 
 
 void AstTyper::VisitClassLiteral(ClassLiteral* expr) {}
 
 
 void AstTyper::VisitNativeFunctionLiteral(NativeFunctionLiteral* expr) {
 }
 
 
+void AstTyper::VisitDoExpression(DoExpression* expr) {
+  RECURSE(VisitBlock(expr->block()));
+  RECURSE(VisitVariableProxy(expr->result()));
+  NarrowType(expr, expr->result()->bounds());
+}
+
+
 void AstTyper::VisitConditional(Conditional* expr) {
   // Collect type feedback.
   expr->condition()->RecordToBooleanTypeFeedback(oracle());
 
   RECURSE(Visit(expr->condition()));
   Effects then_effects = EnterEffects();
   RECURSE(Visit(expr->then_expression()));
   ExitEffects();
   Effects else_effects = EnterEffects();
   RECURSE(Visit(expr->else_expression()));
@@ skipping 443 matching lines @@
 void AstTyper::VisitImportDeclaration(ImportDeclaration* declaration) {
 }
 
 
 void AstTyper::VisitExportDeclaration(ExportDeclaration* declaration) {
 }
 
 
 }  // namespace internal
 }  // namespace v8