Rewrite scopes in computed properties in destructured parameters

src/parsing/pattern-rewriter.cc

 // 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.
 
 #include "src/ast/ast.h"
 #include "src/messages.h"
 #include "src/parsing/parameter-initializer-rewriter.h"
 #include "src/parsing/parser.h"
 
 namespace v8 {
@@ skipping 363 matching lines @@
   Expression* expr = factory()->NewDoExpression(block_, temp, pos);
   node->Rewrite(expr);
   block_ = old_block;
   if (block_) {
     block_->statements()->Add(factory()->NewExpressionStatement(expr, pos),
                               zone());
   }
   return set_context(old_context);
 }
 
+// Two cases for scope rewriting the scope of default parameters:
+// - Eagerly parsed arrow functions are initially parsed as having
+//   expressions in the enclosing scope, but when the arrow is encountered,
+//   need to be in the scope of the function.
+// - When an extra declaration scope needs to be inserted to account for
+//   a sloppy eval in a default parameter or function body, the expressions
+//   needs to be in that new inner scope which was added after initial
+//   parsing.
+// Each of these cases can be handled by rewriting the contents of the
+// expression to the current scope. The source scope is typically the outer
+// scope when one case occurs; when both cases occur, both scopes need to
+// be included as the outer scope. (Both rewritings still need to be done
+// to account for lazily parsed arrow functions which hit the second case.)
+// TODO(littledan): Remove the outer_scope parameter of
+//                  RewriteParameterInitializerScope
+void Parser::PatternRewriter::RewriteParameterScopes(Expression* expr) {
+  if (!IsBindingContext()) return;
+  if (descriptor_->declaration_kind != DeclarationDescriptor::PARAMETER) return;
+  if (!scope()->is_arrow_scope() && !scope()->is_block_scope()) return;
+
+  // Either this scope is an arrow scope or a declaration block scope.
+  DCHECK(scope()->is_declaration_scope());
+
+  if (scope()->outer_scope()->is_arrow_scope() && scope()->is_block_scope()) {
+    RewriteParameterInitializerScope(parser_->stack_limit(), expr,
+                                     scope()->outer_scope()->outer_scope(),
+                                     scope());
+  }
+  RewriteParameterInitializerScope(parser_->stack_limit(), expr,
+                                   scope()->outer_scope(), scope());
+}
 
 void Parser::PatternRewriter::VisitObjectLiteral(ObjectLiteral* pattern,
                                                  Variable** temp_var) {
   auto temp = *temp_var = CreateTempVar(current_value_);
 
   block_->statements()->Add(parser_->BuildAssertIsCoercible(temp), zone());
 
   for (ObjectLiteralProperty* property : *pattern->properties()) {
     PatternContext context = SetInitializerContextIfNeeded(property->value());
+
+    // Computed property names contain expressions which might require
+    // scope rewriting.
+    if (!property->key()->IsLiteral()) RewriteParameterScopes(property->key());
+
     RecurseIntoSubpattern(
         property->value(),
         factory()->NewProperty(factory()->NewVariableProxy(temp),
                                property->key(), RelocInfo::kNoPosition));
     set_context(context);
   }
 }
 
 
 void Parser::PatternRewriter::VisitObjectLiteral(ObjectLiteral* node) {
@@ skipping 267 matching lines @@
   if (IsInitializerContext()) {
     Expression* is_undefined = factory()->NewCompareOperation(
         Token::EQ_STRICT, factory()->NewVariableProxy(temp),
         factory()->NewUndefinedLiteral(RelocInfo::kNoPosition),
         RelocInfo::kNoPosition);
     value = factory()->NewConditional(is_undefined, initializer,
                                       factory()->NewVariableProxy(temp),
                                       RelocInfo::kNoPosition);
   }
 
-  // Two cases for scope rewriting the scope of default parameters:
-  // - Eagerly parsed arrow functions are initially parsed as having
-  //   initializers in the enclosing scope, but when the arrow is encountered,
-  //   need to be in the scope of the function.
-  // - When an extra declaration scope needs to be inserted to account for
-  //   a sloppy eval in a default parameter or function body, the initializer
-  //   needs to be in that new inner scope which was added after initial
-  //   parsing.
-  // Each of these cases can be handled by rewriting the contents of the
-  // initializer to the current scope. The source scope is typically the outer
-  // scope when one case occurs; when both cases occur, both scopes need to
-  // be included as the outer scope. (Both rewritings still need to be done
-  // to account for lazily parsed arrow functions which hit the second case.)
-  // TODO(littledan): Remove the outer_scope parameter of
-  //                  RewriteParameterInitializerScope
-  if (IsBindingContext() &&
-      descriptor_->declaration_kind == DeclarationDescriptor::PARAMETER &&
-      (scope()->is_arrow_scope() || scope()->is_block_scope())) {
-    if (scope()->outer_scope()->is_arrow_scope() && scope()->is_block_scope()) {
-      RewriteParameterInitializerScope(parser_->stack_limit(), initializer,
-                                       scope()->outer_scope()->outer_scope(),
-                                       scope());
-    }
-    RewriteParameterInitializerScope(parser_->stack_limit(), initializer,
-                                     scope()->outer_scope(), scope());
-  }
+  // Initializer may have been parsed in the wrong scope.
+  RewriteParameterScopes(initializer);
 
   PatternContext old_context = SetAssignmentContextIfNeeded(initializer);
   RecurseIntoSubpattern(node->target(), value);
   set_context(old_context);
 }
 
 
 // =============== AssignmentPattern only ==================
 
 void Parser::PatternRewriter::VisitProperty(v8::internal::Property* node) {
@@ skipping 59 matching lines @@
 NOT_A_PATTERN(TryFinallyStatement)
 NOT_A_PATTERN(UnaryOperation)
 NOT_A_PATTERN(VariableDeclaration)
 NOT_A_PATTERN(WhileStatement)
 NOT_A_PATTERN(WithStatement)
 NOT_A_PATTERN(Yield)
 
 #undef NOT_A_PATTERN
 }  // namespace internal
 }  // namespace v8