Re-scope inner scopes in arrow parameter initializers

This patch correctly re-scopes inner scopes that can appear in do
expressions used as initializers to arrow parameters.

R=rossberg@chromium.org
BUG=v8:4904
LOG=N

Review URL: https://codereview.chromium.org/1887743002

Cr-Commit-Position: refs/heads/master@{#35542}

src/ast/ast-expression-visitor.h

@@ -27,10 +27,10 @@ class AstExpressionVisitor : public AstVisitor {
   virtual void VisitExpression(Expression* expression) = 0;
   int depth() { return depth_; }
 
- private:
   void VisitDeclarations(ZoneList<Declaration*>* d) override;
   void VisitStatements(ZoneList<Statement*>* s) override;
 
+ private:
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
 
 #define DECLARE_VISIT(type) void Visit##type(type* node) override;

src/parsing/parameter-initializer-rewriter.cc

@@ -29,6 +29,10 @@ class Rewriter final : public AstExpressionVisitor {
   void VisitClassLiteral(ClassLiteral* expr) override;
   void VisitVariableProxy(VariableProxy* expr) override;
 
+  void VisitBlock(Block* stmt) override;
+  void VisitTryCatchStatement(TryCatchStatement* stmt) override;
+  void VisitWithStatement(WithStatement* stmt) override;
+
   Scope* old_scope_;
   Scope* new_scope_;
 };
@@ -73,6 +77,26 @@ void Rewriter::VisitVariableProxy(VariableProxy* proxy) {
 }
 
 
+void Rewriter::VisitBlock(Block* stmt) {
+  if (stmt->scope() != nullptr)
+    stmt->scope()->ReplaceOuterScope(new_scope_);
+  else
+    VisitStatements(stmt->statements());
+}
+
+
+void Rewriter::VisitTryCatchStatement(TryCatchStatement* stmt) {
+  Visit(stmt->try_block());
+  stmt->scope()->ReplaceOuterScope(new_scope_);
+}
+
+
+void Rewriter::VisitWithStatement(WithStatement* stmt) {
+  Visit(stmt->expression());
+  stmt->scope()->ReplaceOuterScope(new_scope_);
+}
+
+
 }  // anonymous namespace
 
 

test/mjsunit/harmony/regress/regress-4904.js

+// Copyright 2015 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.
+
+// Flags: --harmony-do-expressions
+
+(function testCatchScopeInDoExpression() {
+  var f = (s = 17, y = do { try { throw 25; } catch(e) { s += e; }; }) => s;
+  var result = f();
+  assertEquals(result, 42);
+})();
+
+(function testCatchScopeInDoExpression() {
+  var f = (s = 17, y = do { let t; try { throw 25; } catch(e) { s += e; }; }) => s;
+  var result = f();
+  assertEquals(result, 42);
+})();
+
+(function testCatchScopeInDoExpression() {
+  let t1;
+  var f = (s = 17, y = do { let t2; try { throw 25; } catch(e) { s += e; }; }) => s;
+  var result = f();
+  assertEquals(result, 42);
+})();

test/mjsunit/mjsunit.status

@@ -794,10 +794,6 @@
   # objects.
   'es6/mirror-collections': [FAIL],
 
-  # TODO(mythria, 4904): Parser bug. It creates incorrectly nested scopes
-  # for do expressions in arrow functions.
-  'harmony/regress/regress-4658': [FAIL, ['mode == release and dcheck_always_on == False', PASS],],
-
   # TODO(rmcilroy, 4680): Script throws RangeError as expected, but does so during
   # eager compile of the whole script instead of during lazy compile of the function
   # f(), so we can't catch the exception in the try/catch. Skip because on some