[es6] parse destructuring assignment

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 7a68e835ff2870e5397c2be37f7f17acb4fed00f..acf00b80f46e7b78f97c75f653a0c6bce0f37f80 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -570,7 +570,86 @@ class ParserBase : public Traits {
       bool HasError() const { return location.IsValid(); }
     };
 
-    ExpressionClassifier() {}
+    ExpressionClassifier() : lhs_type_(TARGET_NONE), assigned_(false) {}
+
+    enum AssignmentTargetType {
+      TARGET_NONE = 0,
+
+      // IdentifierReference
+      TARGET_IDENTIFIER,
+
+      // MemberExpression . <property name>
+      // MemberExpression [<property name>]
+      TARGET_PROPERTY,
+
+      // MemberExpression ( arguments )
+      // new MemberExpression ( arguments )
+      // MemberExpression TemplateLiteral
+      TARGET_CALL,
+
+      // this
+      // Literal
+      // ArrayLiteral
+      // ObjectLiteral
+      // FunctionExpression
+      // ClassExpression
+      // GeneratorExpression
+      // RegularExpressionLiteral
+      // TemplateLiteral
+      // CoverParenthesizedExpressionAndArrowParameterList
+      TARGET_PRIMARY,
+
+      // new.target
+      // yield (in generator)
+      TARGET_RESTRICTED,
+
+      // UnaryExpression
+      // MultiplicativeExpression
+      // AdditiveExpression
+      // ShiftExpression
+      // RelationalExpression
+      // EqualityExpression
+      // BitwiseANDExpression
+      // BitwiseXORExpression
+      // BitwiseORExpression
+      // LogicalANDExpression
+      // LogicalORExpression
+      // ConditionalExpression
+      // AssignmentExpression
+      // ... Pretty much any binary operator
+      UNACCEPTABLE_TARGET,
+
+      // BindingPattern
+      TARGET_PATTERN
+    };
+
+    inline AssignmentTargetType AssignmentTarget() const { return lhs_type_; }
+
+    inline void AppendAssignmentTarget(AssignmentTargetType type) {
+      if (lhs_type_ == UNACCEPTABLE_TARGET) return;
+      lhs_type_ = type;
+    }
+
+    inline void ReportInvalidSimpleAssignmentTarget() {
+      lhs_type_ = UNACCEPTABLE_TARGET;
+    }
+
+    inline bool IsValidSimpleAssignmentTarget() const {
+      // Only identifiers and properties are valid targets.
+      return lhs_type_ >= TARGET_IDENTIFIER && lhs_type_ <= TARGET_PROPERTY;
+    }
+
+    inline bool IsPatternAssignmentElement() const {
+      // Any AssignmentElement for which IsValidSimpleAssignmentTarget is false.
+      // Used for nested AssignmentPatterns
+      return lhs_type_ == TARGET_PATTERN && is_valid_assignment_pattern();
+    }
+
+    void set_assigned() { assigned_ = true; }
+
+    bool is_destructuring_assignment() const {
+      return lhs_type_ == TARGET_PATTERN && assigned_;
+    }
 
     bool is_valid_expression() const { return !expression_error_.HasError(); }
 
@@ -707,6 +786,13 @@ class ParserBase : public Traits {
                         ArrowFormalParametersProduction),
     };
 
+    void AccumulateValidSimpleAssignmentTarget(
+        const ExpressionClassifier& inner) {
+      if (lhs_type_ != UNACCEPTABLE_TARGET) {
+        lhs_type_ = inner.lhs_type_;
+      }
+    }
+
     void Accumulate(const ExpressionClassifier& inner,
                     unsigned productions = StandardProductions) {
       if (productions & ExpressionProduction && is_valid_expression()) {
@@ -755,6 +841,8 @@ class ParserBase : public Traits {
     }
 
    private:
+    AssignmentTargetType lhs_type_;
+    bool assigned_;
     Error expression_error_;
     Error binding_pattern_error_;
     Error assignment_pattern_error_;
@@ -764,6 +852,20 @@ class ParserBase : public Traits {
     Error strong_mode_formal_parameter_error_;
   };
 
+  ExpressionT CheckDestructuringAssignment(ExpressionT expr,
+                                           ExpressionClassifier* classifier,
+                                           bool* ok) {
+    if (classifier->is_destructuring_assignment()) {
+      if (!classifier->is_valid_assignment_pattern()) {
+        this->ReportClassifierError(classifier->assignment_pattern_error());
+        *ok = false;
+        return this->EmptyExpression();
+      }
+      return Traits::RewriteDestructuringAssignment(expr);
+    }
+    return expr;
+  }
+
   void ReportClassifierError(
       const typename ExpressionClassifier::Error& error) {
     Traits::ReportMessageAt(error.location, error.message, error.arg,
@@ -885,9 +987,15 @@ class ParserBase : public Traits {
   typename Traits::Type::ExpressionList ParseArguments(
       Scanner::Location* first_spread_pos, ExpressionClassifier* classifier,
       bool* ok);
-  ExpressionT ParseAssignmentExpression(bool accept_IN,
+  // TODO(caitp): Use enums for accept_IN / pattern_lhs?
+  ExpressionT ParseAssignmentExpression(bool accept_IN, bool pattern_lhs,
                                         ExpressionClassifier* classifier,
                                         bool* ok);
+  ExpressionT ParseAssignmentExpression(bool accept_IN,
+                                        ExpressionClassifier* classifier,
+                                        bool* ok) {
+    return ParseAssignmentExpression(accept_IN, false, classifier, ok);
+  }
   ExpressionT ParseYieldExpression(ExpressionClassifier* classifier, bool* ok);
   ExpressionT ParseConditionalExpression(bool accept_IN,
                                          ExpressionClassifier* classifier,
@@ -1840,6 +1948,11 @@ class PreParserTraits {
                                            PreParserExpressionList args,
                                            int pos);
 
+  inline PreParserExpression RewriteDestructuringAssignment(
+      PreParserExpression expr) {
+    return expr;
+  }
+
  private:
   PreParser* pre_parser_;
 };
@@ -2317,6 +2430,8 @@ ParserBase<Traits>::ParsePrimaryExpression(ExpressionClassifier* classifier,
   int end_pos = scanner()->peek_location().end_pos;
   ExpressionT result = this->EmptyExpression();
   Token::Value token = peek();
+  typename ExpressionClassifier::AssignmentTargetType lhs_part =
+      ExpressionClassifier::TARGET_PRIMARY;
   switch (token) {
     case Token::THIS: {
       BindingPatternUnexpectedToken(classifier);
@@ -2357,6 +2472,7 @@ ParserBase<Traits>::ParsePrimaryExpression(ExpressionClassifier* classifier,
     case Token::YIELD:
     case Token::FUTURE_STRICT_RESERVED_WORD: {
       // Using eval or arguments in this context is OK even in strict mode.
+      lhs_part = ExpressionClassifier::TARGET_IDENTIFIER;
       IdentifierT name = ParseAndClassifyIdentifier(classifier, CHECK_OK);
       result = this->ExpressionFromIdentifier(name, beg_pos, end_pos, scope_,
                                               factory());
@@ -2420,8 +2536,17 @@ ParserBase<Traits>::ParsePrimaryExpression(ExpressionClassifier* classifier,
         // Heuristically try to detect immediately called functions before
         // seeing the call parentheses.
         parenthesized_function_ = (peek() == Token::FUNCTION);
-        result = this->ParseExpression(true, classifier, CHECK_OK);
+        ExpressionClassifier expr_classifier;
+        result = this->ParseExpression(true, &expr_classifier, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
+        if (peek() == Token::ARROW || parenthesized_function_) {
+          classifier->Accumulate(
+              expr_classifier,
+              ExpressionClassifier::ArrowFormalParametersProduction |
+                  ExpressionClassifier::FormalParametersProduction);
+        } else {
+          lhs_part = expr_classifier.AssignmentTarget();
+        }
       }
       break;
 
@@ -2457,6 +2582,7 @@ ParserBase<Traits>::ParsePrimaryExpression(ExpressionClassifier* classifier,
     case Token::MOD:
       if (allow_natives() || extension_ != NULL) {
         result = this->ParseV8Intrinsic(CHECK_OK);
+        lhs_part = ExpressionClassifier::TARGET_CALL;
         break;
       }
       // If we're not allowing special syntax we fall-through to the
@@ -2469,6 +2595,10 @@ ParserBase<Traits>::ParsePrimaryExpression(ExpressionClassifier* classifier,
     }
   }
 
+  if (*ok && lhs_part != ExpressionClassifier::TARGET_NONE) {
+    classifier->AppendAssignmentTarget(lhs_part);
+  }
+
   return result;
 }
 
@@ -2491,18 +2621,27 @@ typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParseExpression(
   //   AssignmentExpression
   //   Expression ',' AssignmentExpression
 
-  ExpressionClassifier binding_classifier;
+  ExpressionClassifier expr_classifier;
   ExpressionT result =
-      this->ParseAssignmentExpression(accept_IN, &binding_classifier, CHECK_OK);
-  classifier->Accumulate(binding_classifier,
-                         ExpressionClassifier::AllProductions);
+      this->ParseAssignmentExpression(accept_IN, &expr_classifier, CHECK_OK);
+  classifier->AccumulateValidSimpleAssignmentTarget(expr_classifier);
+  classifier->Accumulate(expr_classifier,
+                         expr_classifier.is_destructuring_assignment()
+                             ? ExpressionClassifier::PatternProductions
+                             : ExpressionClassifier::AllProductions);
   while (peek() == Token::COMMA) {
     Expect(Token::COMMA, CHECK_OK);
     int pos = position();
-    ExpressionT right = this->ParseAssignmentExpression(
-        accept_IN, &binding_classifier, CHECK_OK);
-    classifier->Accumulate(binding_classifier,
-                           ExpressionClassifier::AllProductions);
+    classifier->ReportInvalidSimpleAssignmentTarget();
+    ExpressionClassifier expr_classifier;
+    ExpressionT right =
+        this->ParseAssignmentExpression(accept_IN, &expr_classifier, CHECK_OK);
+    classifier->Accumulate(expr_classifier,
+                           expr_classifier.is_destructuring_assignment()
+                               ? ExpressionClassifier::PatternProductions
+                               : ExpressionClassifier::AllProductions);
+
+
     result = factory()->NewBinaryOperation(Token::COMMA, result, right, pos);
   }
   return result;
@@ -2522,6 +2661,7 @@ typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParseArrayLiteral(
   while (peek() != Token::RBRACK) {
     bool seen_spread = false;
     ExpressionT elem = this->EmptyExpression();
+    ExpressionClassifier element_classifier;
     if (peek() == Token::COMMA) {
       if (is_strong(language_mode())) {
         ReportMessageAt(scanner()->peek_location(),
@@ -2541,7 +2681,16 @@ typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParseArrayLiteral(
       elem = factory()->NewSpread(argument, start_pos);
       seen_spread = true;
     } else {
-      elem = this->ParseAssignmentExpression(true, classifier, CHECK_OK);
+      int start_pos = peek_position();
+      elem =
+          this->ParseAssignmentExpression(true, &element_classifier, CHECK_OK);
+      if (!element_classifier.IsValidSimpleAssignmentTarget() &&
+          !element_classifier.IsPatternAssignmentElement()) {
+        Scanner::Location location(start_pos, scanner()->location().end_pos);
+        classifier->RecordAssignmentPatternError(
+            location, MessageTemplate::kInvalidDestructuringAssignmentTarget);
+      }
+      classifier->Accumulate(element_classifier);
     }
     values->Add(elem, zone_);
     if (peek() != Token::RBRACK) {
@@ -2635,13 +2784,16 @@ ParserBase<Traits>::ParsePropertyDefinition(
   bool is_set = false;
   bool name_is_static = false;
   bool is_generator = allow_harmony_object_literals_ && Check(Token::MUL);
-
+  // Classify destructuring assignment target for ObjectAssignmentPattern
+  ExpressionClassifier property_classifier;
   Token::Value name_token = peek();
   int next_beg_pos = scanner()->peek_location().beg_pos;
   int next_end_pos = scanner()->peek_location().end_pos;
+  int value_start = next_beg_pos;
+  int value_end = next_end_pos;
   ExpressionT name_expression = ParsePropertyName(
-      &name, &is_get, &is_set, &name_is_static, is_computed_name, classifier,
-      CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+      &name, &is_get, &is_set, &name_is_static, is_computed_name,
+      &property_classifier, CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
   if (fni_ != nullptr && !*is_computed_name) {
     this->PushLiteralName(fni_, name);
@@ -2655,12 +2807,16 @@ ParserBase<Traits>::ParsePropertyDefinition(
                              CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     }
     Consume(Token::COLON);
+    property_classifier = ExpressionClassifier();
+    value_start = peek_position();
     value = this->ParseAssignmentExpression(
-        true, classifier, CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
-
+        true, &property_classifier,
+        CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+    value_end = scanner()->location().end_pos;
   } else if (is_generator ||
              (allow_harmony_object_literals_ && peek() == Token::LPAREN)) {
     // Concise Method
+    property_classifier.ReportInvalidSimpleAssignmentTarget();
     if (!*is_computed_name) {
       checker->CheckProperty(name_token, kMethodProperty, is_static,
                              is_generator,
@@ -2691,10 +2847,12 @@ ParserBase<Traits>::ParsePropertyDefinition(
 
   } else if (in_class && name_is_static && !is_static) {
     // static MethodDefinition
+    property_classifier.ReportInvalidSimpleAssignmentTarget();
     return ParsePropertyDefinition(checker, true, has_extends, true,
                                    is_computed_name, nullptr, classifier, ok);
   } else if (is_get || is_set) {
     // Accessor
+    property_classifier.ReportInvalidSimpleAssignmentTarget();
     name = this->EmptyIdentifier();
     bool dont_care = false;
     name_token = peek();
@@ -2726,6 +2884,11 @@ ParserBase<Traits>::ParsePropertyDefinition(
           factory()->NewStringLiteral(name, name_expression->position());
     }
 
+    value_end = scanner()->location().end_pos;
+    Scanner::Location location(value_start, value_end);
+    classifier->RecordAssignmentPatternError(
+        location, MessageTemplate::kInvalidDestructuringAssignmentTarget);
+
     return factory()->NewObjectLiteralProperty(
         name_expression, value,
         is_get ? ObjectLiteralProperty::GETTER : ObjectLiteralProperty::SETTER,
@@ -2744,7 +2907,8 @@ ParserBase<Traits>::ParsePropertyDefinition(
       Consume(Token::ASSIGN);
       ExpressionClassifier rhs_classifier;
       ExpressionT rhs = this->ParseAssignmentExpression(
-          true, &rhs_classifier, CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+          true, true, &rhs_classifier,
+          CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
       classifier->AccumulateReclassifyingAsPattern(rhs_classifier);
       value = factory()->NewAssignment(Token::ASSIGN, lhs, rhs,
                                        RelocInfo::kNoPosition);
@@ -2761,6 +2925,14 @@ ParserBase<Traits>::ParsePropertyDefinition(
     return this->EmptyObjectLiteralProperty();
   }
 
+  if (!property_classifier.IsValidSimpleAssignmentTarget() &&
+      !property_classifier.IsPatternAssignmentElement()) {
+    Scanner::Location location(value_start, value_end);
+    classifier->RecordAssignmentPatternError(
+        location, MessageTemplate::kInvalidDestructuringAssignmentTarget);
+  }
+  classifier->Accumulate(property_classifier);
+
   return factory()->NewObjectLiteralProperty(name_expression, value, is_static,
                                              *is_computed_name);
 }
@@ -2903,7 +3075,7 @@ typename Traits::Type::ExpressionList ParserBase<Traits>::ParseArguments(
 // Precedence = 2
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
-ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
+ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN, bool pattern_lhs,
                                               ExpressionClassifier* classifier,
                                               bool* ok) {
   // AssignmentExpression ::
@@ -2918,6 +3090,11 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
     return this->ParseYieldExpression(classifier, ok);
   }
 
+  bool maybe_assignment_pattern =
+      allow_harmony_destructuring() &&
+      classifier->is_valid_assignment_pattern() &&
+      (peek() == Token::LBRACK || peek() == Token::LBRACE);
+
   if (fni_ != NULL) fni_->Enter();
   ParserBase<Traits>::Checkpoint checkpoint(this);
   ExpressionClassifier arrow_formals_classifier;
@@ -2926,13 +3103,26 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
     // formal parameter list.
     ArrowFormalParametersUnexpectedToken(&arrow_formals_classifier);
   }
+
   ExpressionT expression = this->ParseConditionalExpression(
       accept_IN, &arrow_formals_classifier, CHECK_OK);
+
+  if (!arrow_formals_classifier.is_valid_assignment_pattern()) {
+    if (maybe_assignment_pattern && peek() == Token::ASSIGN) {
+      // ObjectAssignmentPattern or ArrayAssignmentPattern contains an error
+      ReportClassifierError(
+          arrow_formals_classifier.assignment_pattern_error());
+      *ok = false;
+      return this->EmptyExpression();
+    }
+  }
+
   classifier->Accumulate(arrow_formals_classifier);
 
   if (allow_harmony_arrow_functions() && peek() == Token::ARROW) {
     checkpoint.Restore();
     BindingPatternUnexpectedToken(classifier);
+    classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_PRIMARY);
     ValidateArrowFormalParameters(&arrow_formals_classifier, expression,
                                   CHECK_OK);
     Scanner::Location loc(lhs_location.beg_pos, scanner()->location().end_pos);
@@ -2957,6 +3147,29 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
   classifier->Accumulate(arrow_formals_classifier,
                          ExpressionClassifier::FormalParametersProduction);
 
+  bool valid_destructuring_assignment_target =
+      arrow_formals_classifier.IsValidSimpleAssignmentTarget();
+  if (valid_destructuring_assignment_target) {
+    classifier->AccumulateValidSimpleAssignmentTarget(arrow_formals_classifier);
+  } else if (!maybe_assignment_pattern ||
+             !arrow_formals_classifier.is_valid_assignment_pattern()) {
+    // Potentially a bad DestructuringAssignmentTarget
+    classifier->RecordAssignmentPatternError(
+        Scanner::Location(lhs_location.beg_pos, scanner()->location().end_pos),
+        MessageTemplate::kInvalidDestructuringAssignmentTarget);
+  }
+
+  if (maybe_assignment_pattern) {
+    classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_PATTERN);
+  }
+
+  if (pattern_lhs && peek() != Token::ASSIGN) {
+    // If LHS was an AssignmentPattern and there is no additional assignment,
+    // ensure that the RHS is a valid expression
+    ValidateExpression(classifier, CHECK_OK);
+    return expression;
+  }
+
   if (!Token::IsAssignmentOp(peek())) {
     if (fni_ != NULL) fni_->Leave();
     // Parsed conditional expression only (no assignment).
@@ -2967,9 +3180,12 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
     BindingPatternUnexpectedToken(classifier);
   }
 
-  expression = this->CheckAndRewriteReferenceExpression(
-      expression, lhs_location, MessageTemplate::kInvalidLhsInAssignment,
-      CHECK_OK);
+  if (!maybe_assignment_pattern || peek() != Token::ASSIGN) {
+    expression = this->CheckAndRewriteReferenceExpression(
+        expression, lhs_location, MessageTemplate::kInvalidLhsInAssignment,
+        CHECK_OK);
+  }
+
   expression = this->MarkExpressionAsAssigned(expression);
 
   Token::Value op = Next();  // Get assignment operator.
@@ -2977,12 +3193,14 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
     classifier->RecordBindingPatternError(scanner()->location(),
                                           MessageTemplate::kUnexpectedToken,
                                           Token::String(op));
+  } else {
+    classifier->set_assigned();
   }
   int pos = position();
 
   ExpressionClassifier rhs_classifier;
-  ExpressionT right =
-      this->ParseAssignmentExpression(accept_IN, &rhs_classifier, CHECK_OK);
+  ExpressionT right = this->ParseAssignmentExpression(
+      accept_IN, maybe_assignment_pattern, &rhs_classifier, CHECK_OK);
   classifier->AccumulateReclassifyingAsPattern(rhs_classifier);
 
   // TODO(1231235): We try to estimate the set of properties set by
@@ -3011,7 +3229,8 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
     fni_->Leave();
   }
 
-  return factory()->NewAssignment(op, expression, right, pos);
+  ExpressionT result = factory()->NewAssignment(op, expression, right, pos);
+  return this->CheckDestructuringAssignment(result, classifier, CHECK_OK);
 }
 
 template <class Traits>
@@ -3078,6 +3297,7 @@ ParserBase<Traits>::ParseConditionalExpression(bool accept_IN,
       this->ParseBinaryExpression(4, accept_IN, classifier, CHECK_OK);
   if (peek() != Token::CONDITIONAL) return expression;
   BindingPatternUnexpectedToken(classifier);
+  classifier->ReportInvalidSimpleAssignmentTarget();
   Consume(Token::CONDITIONAL);
   // In parsing the first assignment expression in conditional
   // expressions we always accept the 'in' keyword; see ECMA-262,
@@ -3102,6 +3322,7 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN,
     // prec1 >= 4
     while (Precedence(peek(), accept_IN) == prec1) {
       BindingPatternUnexpectedToken(classifier);
+      classifier->ReportInvalidSimpleAssignmentTarget();
       Token::Value op = Next();
       Scanner::Location op_location = scanner()->location();
       int pos = position();
@@ -3164,7 +3385,7 @@ ParserBase<Traits>::ParseUnaryExpression(ExpressionClassifier* classifier,
   Token::Value op = peek();
   if (Token::IsUnaryOp(op)) {
     BindingPatternUnexpectedToken(classifier);
-
+    classifier->ReportInvalidSimpleAssignmentTarget();
     op = Next();
     int pos = position();
     ExpressionT expression = ParseUnaryExpression(classifier, CHECK_OK);
@@ -3186,6 +3407,7 @@ ParserBase<Traits>::ParseUnaryExpression(ExpressionClassifier* classifier,
     return this->BuildUnaryExpression(expression, op, pos, factory());
   } else if (Token::IsCountOp(op)) {
     BindingPatternUnexpectedToken(classifier);
+    classifier->ReportInvalidSimpleAssignmentTarget();
     op = Next();
     Scanner::Location lhs_location = scanner()->peek_location();
     ExpressionT expression = this->ParseUnaryExpression(classifier, CHECK_OK);
@@ -3218,7 +3440,7 @@ ParserBase<Traits>::ParsePostfixExpression(ExpressionClassifier* classifier,
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       Token::IsCountOp(peek())) {
     BindingPatternUnexpectedToken(classifier);
-
+    classifier->ReportInvalidSimpleAssignmentTarget();
     expression = this->CheckAndRewriteReferenceExpression(
         expression, lhs_location, MessageTemplate::kInvalidLhsInPostfixOp,
         CHECK_OK);
@@ -3249,9 +3471,11 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
     switch (peek()) {
       case Token::LBRACK: {
         BindingPatternUnexpectedToken(classifier);
+        classifier->AppendAssignmentTarget(
+            ExpressionClassifier::TARGET_PROPERTY);
         Consume(Token::LBRACK);
         int pos = position();
-        ExpressionT index = ParseExpression(true, classifier, CHECK_OK);
+        ExpressionT index = ParseExpression(true, CHECK_OK);
         result = factory()->NewProperty(result, index, pos);
         Expect(Token::RBRACK, CHECK_OK);
         break;
@@ -3259,7 +3483,7 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
 
       case Token::LPAREN: {
         BindingPatternUnexpectedToken(classifier);
-
+        classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_CALL);
         if (is_strong(language_mode()) && this->IsIdentifier(result) &&
             this->IsEval(this->AsIdentifier(result))) {
           ReportMessage(MessageTemplate::kStrongDirectEval);
@@ -3310,6 +3534,8 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
 
       case Token::PERIOD: {
         BindingPatternUnexpectedToken(classifier);
+        classifier->AppendAssignmentTarget(
+            ExpressionClassifier::TARGET_PROPERTY);
         Consume(Token::PERIOD);
         int pos = position();
         IdentifierT name = ParseIdentifierName(CHECK_OK);
@@ -3349,6 +3575,7 @@ ParserBase<Traits>::ParseMemberWithNewPrefixesExpression(
 
   if (peek() == Token::NEW) {
     BindingPatternUnexpectedToken(classifier);
+    classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_CALL);
     Consume(Token::NEW);
     int new_pos = position();
     ExpressionT result = this->EmptyExpression();
@@ -3400,7 +3627,7 @@ ParserBase<Traits>::ParseMemberExpression(ExpressionClassifier* classifier,
   ExpressionT result = this->EmptyExpression();
   if (peek() == Token::FUNCTION) {
     BindingPatternUnexpectedToken(classifier);
-
+    classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_PRIMARY);
     Consume(Token::FUNCTION);
     int function_token_position = position();
     bool is_generator = Check(Token::MUL);
@@ -3589,12 +3816,14 @@ ParserBase<Traits>::ParseSuperExpression(bool is_new,
   if (IsConciseMethod(kind) || IsAccessorFunction(kind) ||
       i::IsConstructor(kind)) {
     if (peek() == Token::PERIOD || peek() == Token::LBRACK) {
+      classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_PROPERTY);
       scope->RecordSuperPropertyUsage();
       return this->SuperPropertyReference(scope_, factory(), pos);
     }
     // new super() is never allowed.
     // super() is only allowed in derived constructor
     if (!is_new && peek() == Token::LPAREN && IsSubclassConstructor(kind)) {
+      classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_CALL);
       if (is_strong(language_mode())) {
         // Super calls in strong mode are parsed separately.
         ReportMessageAt(scanner()->location(),
@@ -3625,10 +3854,14 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
     switch (peek()) {
       case Token::LBRACK: {
         BindingPatternUnexpectedToken(classifier);
-
+        classifier->AppendAssignmentTarget(
+            ExpressionClassifier::TARGET_PROPERTY);
         Consume(Token::LBRACK);
         int pos = position();
-        ExpressionT index = this->ParseExpression(true, classifier, CHECK_OK);
+        // Ignore pattern errors within expression
+        ExpressionClassifier prop_classifier;
+        ExpressionT index =
+            this->ParseExpression(true, &prop_classifier, CHECK_OK);
         expression = factory()->NewProperty(expression, index, pos);
         if (fni_ != NULL) {
           this->PushPropertyName(fni_, index);
@@ -3638,6 +3871,8 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
       }
       case Token::PERIOD: {
         BindingPatternUnexpectedToken(classifier);
+        classifier->AppendAssignmentTarget(
+            ExpressionClassifier::TARGET_PROPERTY);
 
         Consume(Token::PERIOD);
         int pos = position();
@@ -3652,6 +3887,7 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
       case Token::TEMPLATE_SPAN:
       case Token::TEMPLATE_TAIL: {
         BindingPatternUnexpectedToken(classifier);
+        classifier->AppendAssignmentTarget(ExpressionClassifier::TARGET_CALL);
         int pos;
         if (scanner()->current_token() == Token::IDENTIFIER) {
           pos = position();
@@ -3663,8 +3899,10 @@ ParserBase<Traits>::ParseMemberExpressionContinuation(
             expression->AsFunctionLiteral()->set_should_eager_compile();
           }
         }
+        // Ignore classifying tagged template
+        ExpressionClassifier call_classifier;
         expression =
-            ParseTemplateLiteral(expression, pos, classifier, CHECK_OK);
+            ParseTemplateLiteral(expression, pos, &call_classifier, CHECK_OK);
         break;
       }
       default: