[ESnext] Implement Object Rest

src/parsing/parser-base.h

 // Copyright 2012 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.
 
 #ifndef V8_PARSING_PARSER_BASE_H
 #define V8_PARSING_PARSER_BASE_H
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/bailout-reason.h"
@@ skipping 201 matching lines @@
         default_eager_compile_hint_(FunctionLiteral::kShouldLazyCompile),
         function_literal_id_(0),
         allow_natives_(false),
         allow_tailcalls_(false),
         allow_harmony_do_expressions_(false),
         allow_harmony_function_sent_(false),
         allow_harmony_async_await_(false),
         allow_harmony_restrictive_generators_(false),
         allow_harmony_trailing_commas_(false),
         allow_harmony_class_fields_(false),
-        allow_harmony_object_spread_(false) {}
+        allow_harmony_object_rest_spread_(false) {}
 
 #define ALLOW_ACCESSORS(name)                           \
   bool allow_##name() const { return allow_##name##_; } \
   void set_allow_##name(bool allow) { allow_##name##_ = allow; }
 
   ALLOW_ACCESSORS(natives);
   ALLOW_ACCESSORS(tailcalls);
   ALLOW_ACCESSORS(harmony_do_expressions);
   ALLOW_ACCESSORS(harmony_function_sent);
   ALLOW_ACCESSORS(harmony_async_await);
   ALLOW_ACCESSORS(harmony_restrictive_generators);
   ALLOW_ACCESSORS(harmony_trailing_commas);
   ALLOW_ACCESSORS(harmony_class_fields);
-  ALLOW_ACCESSORS(harmony_object_spread);
+  ALLOW_ACCESSORS(harmony_object_rest_spread);
 
 #undef ALLOW_ACCESSORS
 
   uintptr_t stack_limit() const { return stack_limit_; }
 
   void set_stack_limit(uintptr_t stack_limit) { stack_limit_ = stack_limit; }
 
   void set_default_eager_compile_hint(
       FunctionLiteral::EagerCompileHint eager_compile_hint) {
     default_eager_compile_hint_ = eager_compile_hint;
@@ skipping 915 matching lines @@
                                 bool* is_async, bool* is_computed_name,
                                 bool* ok);
   ExpressionT ParseObjectLiteral(bool* ok);
   ClassLiteralPropertyT ParseClassPropertyDefinition(
       ClassLiteralChecker* checker, bool has_extends, bool* is_computed_name,
       bool* has_seen_constructor, ClassLiteralProperty::Kind* property_kind,
       bool* is_static, bool* has_name_static_property, bool* ok);
   FunctionLiteralT ParseClassFieldForInitializer(bool has_initializer,
                                                  bool* ok);
   ObjectLiteralPropertyT ParseObjectPropertyDefinition(
-      ObjectLiteralChecker* checker, bool* is_computed_name, bool* ok);
+      ObjectLiteralChecker* checker, bool* is_computed_name,
+      bool* is_rest_property, bool* ok);
   ExpressionListT ParseArguments(Scanner::Location* first_spread_pos,
                                  bool maybe_arrow, bool* ok);
   ExpressionListT ParseArguments(Scanner::Location* first_spread_pos,
                                  bool* ok) {
     return ParseArguments(first_spread_pos, false, ok);
   }
 
   ExpressionT ParseAssignmentExpression(bool accept_IN, bool* ok);
   ExpressionT ParseYieldExpression(bool accept_IN, bool* ok);
   ExpressionT ParseConditionalExpression(bool accept_IN, bool* ok);
@@ skipping 269 matching lines @@
   int function_literal_id_;
 
   bool allow_natives_;
   bool allow_tailcalls_;
   bool allow_harmony_do_expressions_;
   bool allow_harmony_function_sent_;
   bool allow_harmony_async_await_;
   bool allow_harmony_restrictive_generators_;
   bool allow_harmony_trailing_commas_;
   bool allow_harmony_class_fields_;
-  bool allow_harmony_object_spread_;
+  bool allow_harmony_object_rest_spread_;
 
   friend class DiscardableZoneScope;
 };
 
 template <typename Impl>
 ParserBase<Impl>::FunctionState::FunctionState(
     FunctionState** function_state_stack, ScopeState** scope_stack,
     DeclarationScope* scope)
     : ScopeState(scope_stack, scope),
       next_materialized_literal_index_(0),
@@ skipping 634 matching lines @@
       Consume(Token::LBRACK);
       ExpressionClassifier computed_name_classifier(this);
       expression = ParseAssignmentExpression(true, CHECK_OK);
       impl()->RewriteNonPattern(CHECK_OK);
       impl()->AccumulateFormalParameterContainmentErrors();
       Expect(Token::RBRACK, CHECK_OK);
       break;
     }
 
     case Token::ELLIPSIS:
-      if (allow_harmony_object_spread()) {
-        // TODO(gsathya): Implement destructuring/rest
-        classifier()->RecordPatternError(scanner()->location(),
-                                         MessageTemplate::kUnexpectedToken);
-
+      if (allow_harmony_object_rest_spread()) {
         *name = impl()->EmptyIdentifier();
         Consume(Token::ELLIPSIS);
         ExpressionClassifier spread_classifier(this);
         expression = ParseAssignmentExpression(true, CHECK_OK);
         impl()->RewriteNonPattern(CHECK_OK);
         impl()->AccumulateFormalParameterContainmentErrors();
         *kind = PropertyKind::kSpreadProperty;
+
+        if (expression->IsAssignment()) {
+          classifier()->RecordPatternError(
+              scanner()->location(),
+              MessageTemplate::kInvalidDestructuringTarget);
+        } else {
+          CheckDestructuringElement(expression, pos,
+                                    scanner()->location().end_pos);
+        }
+
+        if (peek() != Token::RBRACE) {

[adamk, 2017/01/10 23:22:56]

I don't think this is correct, since there could be a comma (unless the grammar
actually forbids that?)

[gsathya, 2017/01/12 21:27:41]

No trailing comma allowed after destructuring property.

+          classifier()->RecordPatternError(scanner()->location(),
+                                           MessageTemplate::kElementAfterRest);
+        }
         return expression;
       }
 
     default:
       *name = ParseIdentifierName(CHECK_OK);
       break;
   }
 
   if (*kind == PropertyKind::kNotSet) {
     SetPropertyKindFromToken(peek(), kind);
@@ skipping 189 matching lines @@
       FunctionLiteral::kNoDuplicateParameters,
       FunctionLiteral::kAnonymousExpression, default_eager_compile_hint_,
       initializer_scope->start_position(), true, GetNextFunctionLiteralId());
   return function_literal;
 }
 
 template <typename Impl>
 typename ParserBase<Impl>::ObjectLiteralPropertyT
 ParserBase<Impl>::ParseObjectPropertyDefinition(ObjectLiteralChecker* checker,
                                                 bool* is_computed_name,
+                                                bool* is_rest_property,
                                                 bool* ok) {
   bool is_get = false;
   bool is_set = false;
   bool is_generator = false;
   bool is_async = false;
   PropertyKind kind = PropertyKind::kNotSet;
 
   IdentifierT name = impl()->EmptyIdentifier();
   Token::Value name_token = peek();
   int next_beg_pos = scanner()->peek_location().beg_pos;
   int next_end_pos = scanner()->peek_location().end_pos;
 
   ExpressionT name_expression = ParsePropertyName(
       &name, &kind, &is_generator, &is_get, &is_set, &is_async,
       is_computed_name, CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
   switch (kind) {
     case PropertyKind::kSpreadProperty:
-      DCHECK(allow_harmony_object_spread());
+      DCHECK(allow_harmony_object_rest_spread());
       DCHECK(!is_get && !is_set && !is_generator && !is_async &&
              !*is_computed_name);
       DCHECK(name_token == Token::ELLIPSIS);
 
       *is_computed_name = true;
+      *is_rest_property = true;
 
       return factory()->NewObjectLiteralProperty(
           impl()->GetLiteralTheHole(kNoSourcePosition), name_expression,
           ObjectLiteralProperty::SPREAD, true);
 
     case PropertyKind::kValueProperty: {
       DCHECK(!is_get && !is_set && !is_generator && !is_async);
 
       if (!*is_computed_name) {
         checker->CheckDuplicateProto(name_token);
@@ skipping 154 matching lines @@
 typename ParserBase<Impl>::ExpressionT ParserBase<Impl>::ParseObjectLiteral(
     bool* ok) {
   // ObjectLiteral ::
   // '{' (PropertyDefinition (',' PropertyDefinition)* ','? )? '}'
 
   int pos = peek_position();
   typename Types::ObjectPropertyList properties =
       impl()->NewObjectPropertyList(4);
   int number_of_boilerplate_properties = 0;
   bool has_computed_names = false;
+  bool has_rest_property = false;
   ObjectLiteralChecker checker(this);
 
   Expect(Token::LBRACE, CHECK_OK);
 
   while (peek() != Token::RBRACE) {
     FuncNameInferrer::State fni_state(fni_);
 
     bool is_computed_name = false;
-    ObjectLiteralPropertyT property =
-        ParseObjectPropertyDefinition(&checker, &is_computed_name, CHECK_OK);
+    bool is_rest_property = false;
+    ObjectLiteralPropertyT property = ParseObjectPropertyDefinition(
+        &checker, &is_computed_name, &is_rest_property, CHECK_OK);
 
     if (is_computed_name) {
       has_computed_names = true;
     }
 
+    if (is_rest_property) {
+      has_rest_property = true;
+    }
+
     // Count CONSTANT or COMPUTED properties to maintain the enumeration order.
     if (!has_computed_names && impl()->IsBoilerplateProperty(property)) {
       number_of_boilerplate_properties++;
     }
     properties->Add(property, zone());
 
     if (peek() != Token::RBRACE) {
       // Need {} because of the CHECK_OK macro.
       Expect(Token::COMMA, CHECK_OK);
     }
 
     if (fni_ != nullptr) fni_->Infer();
   }
   Expect(Token::RBRACE, CHECK_OK);
 
   // Computation of literal_index must happen before pre parse bailout.
   int literal_index = function_state_->NextMaterializedLiteralIndex();
 
-  return factory()->NewObjectLiteral(properties,
-                                     literal_index,
-                                     number_of_boilerplate_properties,
-                                     pos);
+  return factory()->NewObjectLiteral(properties, literal_index,
+                                     number_of_boilerplate_properties, pos,
+                                     has_rest_property);
 }
 
 template <typename Impl>
 typename ParserBase<Impl>::ExpressionListT ParserBase<Impl>::ParseArguments(
     Scanner::Location* first_spread_arg_loc, bool maybe_arrow, bool* ok) {
   // Arguments ::
   //   '(' (AssignmentExpression)*[','] ')'
 
   Scanner::Location spread_arg = Scanner::Location::invalid();
   ExpressionListT result = impl()->NewExpressionList(4);
@@ skipping 2950 matching lines @@
     has_seen_constructor_ = true;
     return;
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_BASE_H