[parser] Allow duplicate __proto__ keys in patterns

This patch subsumes CoverInitializedNameProduction to create an ObjectLiteralProduction which is now used to report the duplicate proto error as well.

This patch also changes ObjectLiteralChecker::CheckProperty
to record an ObjectLiteralProduction error instead of
bailing out immediately. Once we realize that we're in a
pattern, we rewind the error, otherwise we report the
error.

BUG=v8:5121

Review-Url: https://codereview.chromium.org/2255353002
Cr-Commit-Position: refs/heads/master@{#38764}

src/parsing/expression-classifier.h

@@ -22,12 +22,11 @@ namespace internal {
   T(StrictModeFormalParametersProduction, 5)    \
   T(ArrowFormalParametersProduction, 6)         \
   T(LetPatternProduction, 7)                    \
-  T(CoverInitializedNameProduction, 8)          \
+  T(ObjectLiteralProduction, 8)                 \
   T(TailCallExpressionProduction, 9)            \
   T(AsyncArrowFormalParametersProduction, 10)   \
   T(AsyncBindingPatternProduction, 11)
 
-
 template <typename Traits>
 class ExpressionClassifier {
  public:
@@ -74,7 +73,7 @@ class ExpressionClassifier {
     AllProductions =
         (ExpressionProductions | PatternProductions |
          FormalParametersProductions | ArrowFormalParametersProduction |
-         CoverInitializedNameProduction | AsyncArrowFormalParametersProduction)
+         ObjectLiteralProduction | AsyncArrowFormalParametersProduction)
   };
 
   enum FunctionProperties : unsigned {
@@ -187,12 +186,12 @@ class ExpressionClassifier {
     return reported_error(kLetPatternProduction);
   }
 
-  V8_INLINE bool has_cover_initialized_name() const {
-    return !is_valid(CoverInitializedNameProduction);
+  V8_INLINE bool has_object_literal_error() const {
+    return !is_valid(ObjectLiteralProduction);
   }
 
-  V8_INLINE const Error& cover_initialized_name_error() const {
-    return reported_error(kCoverInitializedNameProduction);
+  V8_INLINE const Error& object_literal_error() const {
+    return reported_error(kObjectLiteralProduction);
   }
 
   V8_INLINE bool has_tail_call_expression() const {
@@ -201,6 +200,7 @@ class ExpressionClassifier {
   V8_INLINE const Error& tail_call_expression_error() const {
     return reported_error(kTailCallExpressionProduction);
   }
+
   V8_INLINE const Error& async_arrow_formal_parameters_error() const {
     return reported_error(kAsyncArrowFormalParametersProduction);
   }
@@ -314,12 +314,12 @@ class ExpressionClassifier {
     Add(Error(loc, message, kLetPatternProduction, arg));
   }
 
-  void RecordCoverInitializedNameError(const Scanner::Location& loc,
+  void RecordObjectLiteralError(const Scanner::Location& loc,
                                 MessageTemplate::Template message,
                                 const char* arg = nullptr) {
-    if (has_cover_initialized_name()) return;
-    invalid_productions_ |= CoverInitializedNameProduction;
-    Add(Error(loc, message, kCoverInitializedNameProduction, arg));
+    if (has_object_literal_error()) return;
+    invalid_productions_ |= ObjectLiteralProduction;
+    Add(Error(loc, message, kObjectLiteralProduction, arg));
   }
 
   void RecordTailCallExpressionError(const Scanner::Location& loc,
@@ -330,11 +330,11 @@ class ExpressionClassifier {
     Add(Error(loc, message, kTailCallExpressionProduction, arg));
   }
 
-  void ForgiveCoverInitializedNameError() {
-    if (!(invalid_productions_ & CoverInitializedNameProduction)) return;
-    Error& e = reported_error(kCoverInitializedNameProduction);
+  void ForgiveObjectLiteralError() {
+    if (!(invalid_productions_ & ObjectLiteralProduction)) return;
+    Error& e = reported_error(kObjectLiteralProduction);
     e.kind = kUnusedError;
-    invalid_productions_ &= ~CoverInitializedNameProduction;
+    invalid_productions_ &= ~ObjectLiteralProduction;
   }
 
   void ForgiveAssignmentPatternError() {

src/parsing/parser-base.h

@@ -910,12 +910,12 @@ class ParserBase : public Traits {
 
   void ValidateExpression(const ExpressionClassifier* classifier, bool* ok) {
     if (!classifier->is_valid_expression() ||
-        classifier->has_cover_initialized_name()) {
+        classifier->has_object_literal_error()) {
       const Scanner::Location& a = classifier->expression_error().location;
       const Scanner::Location& b =
-          classifier->cover_initialized_name_error().location;
+          classifier->object_literal_error().location;
       if (a.beg_pos < 0 || (b.beg_pos >= 0 && a.beg_pos > b.beg_pos)) {
-        ReportClassifierError(classifier->cover_initialized_name_error());
+        ReportClassifierError(classifier->object_literal_error());
       } else {
         ReportClassifierError(classifier->expression_error());
       }
@@ -1202,7 +1202,8 @@ class ParserBase : public Traits {
     explicit ObjectLiteralCheckerBase(ParserBase* parser) : parser_(parser) {}
 
     virtual void CheckProperty(Token::Value property, PropertyKind type,
-                               MethodKind method_type, bool* ok) = 0;
+                               MethodKind method_type,
+                               ExpressionClassifier* classifier, bool* ok) = 0;
 
     virtual ~ObjectLiteralCheckerBase() {}
 
@@ -1221,7 +1222,8 @@ class ParserBase : public Traits {
         : ObjectLiteralCheckerBase(parser), has_seen_proto_(false) {}
 
     void CheckProperty(Token::Value property, PropertyKind type,
-                       MethodKind method_type, bool* ok) override;
+                       MethodKind method_type, ExpressionClassifier* classifier,
+                       bool* ok) override;
 
    private:
     bool IsProto() { return this->scanner()->LiteralMatches("__proto__", 9); }
@@ -1236,7 +1238,8 @@ class ParserBase : public Traits {
         : ObjectLiteralCheckerBase(parser), has_seen_constructor_(false) {}
 
     void CheckProperty(Token::Value property, PropertyKind type,
-                       MethodKind method_type, bool* ok) override;
+                       MethodKind method_type, ExpressionClassifier* classifier,
+                       bool* ok) override;
 
    private:
     bool IsConstructor() {
@@ -1980,6 +1983,7 @@ ParserBase<Traits>::ParsePropertyDefinition(
       //    PropertyName ':' AssignmentExpression
       if (!*is_computed_name) {
         checker->CheckProperty(name_token, kValueProperty, MethodKind::kNormal,
+                               classifier,
                                CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
       }
       Consume(Token::COLON);
@@ -2044,7 +2048,7 @@ ParserBase<Traits>::ParsePropertyDefinition(
                                ExpressionClassifier::ExpressionProductions);
         value = factory()->NewAssignment(Token::ASSIGN, lhs, rhs,
                                          kNoSourcePosition);
-        classifier->RecordCoverInitializedNameError(
+        classifier->RecordObjectLiteralError(
             Scanner::Location(next_beg_pos, scanner()->location().end_pos),
             MessageTemplate::kInvalidCoverInitializedName);
 
@@ -2080,6 +2084,7 @@ ParserBase<Traits>::ParsePropertyDefinition(
     //    '*' PropertyName '(' StrictFormalParameters ')' '{' FunctionBody '}'
     if (!*is_computed_name) {
       checker->CheckProperty(name_token, kMethodProperty, method_kind,
+                             classifier,
                              CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     }
 
@@ -2130,6 +2135,7 @@ ParserBase<Traits>::ParsePropertyDefinition(
 
     if (!*is_computed_name) {
       checker->CheckProperty(name_token, kAccessorProperty, method_kind,
+                             classifier,
                              CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     }
 
@@ -2416,7 +2422,7 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
       ExpressionClassifier::ExpressionProductions |
           ExpressionClassifier::PatternProductions |
           ExpressionClassifier::FormalParametersProductions |
-          ExpressionClassifier::CoverInitializedNameProduction |
+          ExpressionClassifier::ObjectLiteralProduction |
           ExpressionClassifier::AsyncArrowFormalParametersProduction,
       false);
 
@@ -2433,7 +2439,7 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
   CheckNoTailCallExpressions(classifier, CHECK_OK);
 
   if (IsValidPattern(expression) && peek() == Token::ASSIGN) {
-    classifier->ForgiveCoverInitializedNameError();
+    classifier->ForgiveObjectLiteralError();
     ValidateAssignmentPattern(classifier, CHECK_OK);
     is_destructuring_assignment = true;
   } else {
@@ -2461,7 +2467,7 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
   classifier->Accumulate(
       &rhs_classifier,
       ExpressionClassifier::ExpressionProductions |
-          ExpressionClassifier::CoverInitializedNameProduction |
+          ExpressionClassifier::ObjectLiteralProduction |
           ExpressionClassifier::AsyncArrowFormalParametersProduction);
 
   // TODO(1231235): We try to estimate the set of properties set by
@@ -3702,7 +3708,7 @@ void ParserBase<Traits>::CheckDestructuringElement(
 template <typename Traits>
 void ParserBase<Traits>::ObjectLiteralChecker::CheckProperty(
     Token::Value property, PropertyKind type, MethodKind method_type,
-    bool* ok) {
+    ExpressionClassifier* classifier, bool* ok) {
   DCHECK(!IsStaticMethod(method_type));
   DCHECK(!IsSpecialMethod(method_type) || type == kMethodProperty);
 
@@ -3710,19 +3716,18 @@ void ParserBase<Traits>::ObjectLiteralChecker::CheckProperty(
 
   if (type == kValueProperty && IsProto()) {
     if (has_seen_proto_) {
-      this->parser()->ReportMessage(MessageTemplate::kDuplicateProto);
-      *ok = false;
+      classifier->RecordObjectLiteralError(
+          this->scanner()->location(), MessageTemplate::kDuplicateProto);
       return;
     }
     has_seen_proto_ = true;
-    return;
   }
 }
 
 template <typename Traits>
 void ParserBase<Traits>::ClassLiteralChecker::CheckProperty(
     Token::Value property, PropertyKind type, MethodKind method_type,
-    bool* ok) {
+    ExpressionClassifier* classifier, bool* ok) {
   DCHECK(type == kMethodProperty || type == kAccessorProperty);
 
   if (property == Token::SMI || property == Token::NUMBER) return;

test/cctest/test-parsing.cc

@@ -6342,6 +6342,7 @@ TEST(DestructuringPositiveTests) {
     "[...rest]",
     "[a,b,...rest]",
     "[a,,...rest]",
+    "{ __proto__: x, __proto__: y}",
     "{arguments: x}",
     "{eval: x}",
     NULL};
@@ -6629,6 +6630,7 @@ TEST(DestructuringAssignmentPositiveTests) {
     "{ x : [ foo()[y] = 10 ] = {} }",
     "{ x : [ y.z = 10 ] = {} }",
     "{ x : [ y[z] = 10 ] = {} }",
+    "{ z : { __proto__: x, __proto__: y } = z }"
 
     "[ x ]",
     "[ foo().x ]",
@@ -6748,6 +6750,8 @@ TEST(DestructuringAssignmentPositiveTests) {
       "var x; (true ? { x = true } = {} : { x = false } = {})",
       "var q, x; (q, { x = 10 } = {});",
       "var { x = 10 } = { x = 20 } = {};",
+      "var { __proto__: x, __proto__: y } = {}",
+      "({ __proto__: x, __proto__: y } = {})",
       "var { x = 10 } = (o = { x = 20 } = {});",
       "var x; (({ x = 10 } = { x = 20 } = {}) => x)({})",
       NULL,

test/test262/test262.status

@@ -359,9 +359,6 @@
   'annexB/built-ins/Object/prototype/__lookupGetter__/this-non-obj': [FAIL],
   'annexB/built-ins/Object/prototype/__lookupSetter__/this-non-obj': [FAIL],
 
-  # https://bugs.chromium.org/p/v8/issues/detail?id=5121
-  'language/expressions/assignment/destructuring/obj-prop-__proto__dup': [FAIL],
-
   # https://bugs.chromium.org/p/v8/issues/detail?id=4973
   'language/literals/numeric/non-octal-decimal-integer-strict': [FAIL],