Reland "[parser] Remove RETURN_IF* part 16"

Change-Id: I44ac330e093a4cbca4540a1948c9365c08f73914
Reviewed-on: https://chromium-review.googlesource.com/c/1310293Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57183}

src/ast/ast.h

@@ -449,9 +449,7 @@ class FunctionDeclaration final : public Declaration {
   friend class AstNodeFactory;
 
   FunctionDeclaration(VariableProxy* proxy, FunctionLiteral* fun, int pos)
-      : Declaration(proxy, pos, kFunctionDeclaration), fun_(fun) {
-    DCHECK_NOT_NULL(fun);
-  }
+      : Declaration(proxy, pos, kFunctionDeclaration), fun_(fun) {}
 
   FunctionLiteral* fun_;
 };

src/parsing/parser-base.h

@@ -1547,7 +1547,7 @@ ParserBase<Impl>::ParseAndClassifyIdentifier() {
     if (impl()->IsEvalOrArguments(name)) {
       if (impl()->IsArguments(name) && scope()->ShouldBanArguments()) {
         ReportMessage(MessageTemplate::kArgumentsDisallowedInInitializer);
-        return impl()->NullIdentifier();
+        return impl()->EmptyIdentifierString();
       }
 
       classifier()->RecordStrictModeFormalParameterError(
@@ -1575,7 +1575,7 @@ ParserBase<Impl>::ParseAndClassifyIdentifier() {
     return impl()->GetSymbol();
   } else {
     ReportUnexpectedToken(next);
-    return impl()->NullIdentifier();
+    return impl()->EmptyIdentifierString();
   }
 }
 
@@ -1594,7 +1594,7 @@ ParserBase<Impl>::ParseIdentifierOrStrictReservedWord(
     *is_strict_reserved = true;
   } else {
     ReportUnexpectedToken(next);
-    return impl()->NullIdentifier();
+    return impl()->EmptyIdentifierString();
   }
 
   return impl()->GetSymbol();
@@ -1606,7 +1606,7 @@ typename ParserBase<Impl>::IdentifierT ParserBase<Impl>::ParseIdentifierName() {
   if (!Token::IsAnyIdentifier(next) && next != Token::ESCAPED_KEYWORD &&
       !Token::IsKeyword(next)) {
     ReportUnexpectedToken(next);
-    return impl()->NullIdentifier();
+    return impl()->EmptyIdentifierString();
   }
 
   return impl()->GetSymbol();
@@ -1628,7 +1628,6 @@ ParserBase<Impl>::ParseIdentifierNameOrPrivateName() {
     name = ParseIdentifierName();
     key = factory()->NewStringLiteral(name, pos);
   }
-  RETURN_IF_PARSE_ERROR;
   impl()->PushLiteralName(name);
   return key;
 }
@@ -2131,7 +2130,6 @@ typename ParserBase<Impl>::ExpressionT ParserBase<Impl>::ParsePropertyName(
   if (*kind == ParsePropertyKind::kNotSet) {
     ParsePropertyKindFromToken(peek(), kind);
   }
-  RETURN_IF_PARSE_ERROR;
   impl()->PushLiteralName(*name);
   return is_array_index ? factory()->NewNumberLiteral(index, pos)
                         : factory()->NewStringLiteral(*name, pos);
@@ -2705,8 +2703,6 @@ ParserBase<Impl>::ParseAssignmentExpression(bool accept_IN) {
     }
 
     scope->set_start_position(lhs_beg_pos);
-    // TODO(verwaest): Disable DCHECKs in failure mode?
-    RETURN_IF_PARSE_ERROR;
     impl()->DeclareArrowFunctionFormalParameters(&parameters, expression, loc);
 
     expression =
@@ -3828,7 +3824,7 @@ ParserBase<Impl>::ParseHoistableDeclaration(
     impl()->GetDefaultStrings(&name, &variable_name);
     name_validity = kSkipFunctionNameCheck;
   } else {
-    bool is_strict_reserved;
+    bool is_strict_reserved = false;
     bool is_await = false;
     name = ParseIdentifierOrStrictReservedWord(&is_strict_reserved, &is_await);
     name_validity = is_strict_reserved ? kFunctionNameIsStrictReserved
@@ -3837,8 +3833,6 @@ ParserBase<Impl>::ParseHoistableDeclaration(
   }
 
   FuncNameInferrerState fni_state(&fni_);
-  // TODO(verwaest): Remove once we have FailureIdentifier.
-  RETURN_IF_PARSE_ERROR_CUSTOM(NullStatement);
   impl()->PushEnclosingName(name);
 
   FunctionKind kind = FunctionKindFor(flags);
@@ -3862,7 +3856,6 @@ ParserBase<Impl>::ParseHoistableDeclaration(
                                   !scope()->is_declaration_scope() &&
                                   flags == ParseFunctionFlag::kIsNormal;
 
-  RETURN_IF_PARSE_ERROR_CUSTOM(NullStatement);
   return impl()->DeclareFunction(variable_name, function, mode, pos,
                                  is_sloppy_block_function, names);
 }
@@ -3904,7 +3897,6 @@ typename ParserBase<Impl>::StatementT ParserBase<Impl>::ParseClassDeclaration(
   ExpressionT value = ParseClassLiteral(name, scanner()->location(),
                                         is_strict_reserved, class_token_pos);
   int end_pos = position();
-  RETURN_IF_PARSE_ERROR_CUSTOM(NullStatement);
   return impl()->DeclareClass(variable_name, value, names, class_token_pos,
                               end_pos);
 }
@@ -4138,7 +4130,7 @@ ParserBase<Impl>::ParseArrowFunctionLiteral(
   base::ElapsedTimer timer;
   if (V8_UNLIKELY(FLAG_log_function_events)) timer.Start();
 
-  DCHECK_EQ(Token::ARROW, peek());
+  DCHECK_IMPLIES(!has_error(), peek() == Token::ARROW);
   if (scanner_->HasLineTerminatorBeforeNext()) {
     // ASI inserts `;` after arrow parameters if a line terminator is found.
     // `=> ...` is never a valid expression, so report as syntax error.

src/parsing/parser.cc

@@ -2436,7 +2436,7 @@ void Parser::AddArrowFunctionFormalParameters(
 void Parser::DeclareArrowFunctionFormalParameters(
     ParserFormalParameters* parameters, Expression* expr,
     const Scanner::Location& params_loc) {
-  if (expr->IsEmptyParentheses()) return;
+  if (expr->IsEmptyParentheses() || has_error()) return;
 
   AddArrowFunctionFormalParameters(parameters, expr, params_loc.end_pos);
 
@@ -2446,7 +2446,8 @@ void Parser::DeclareArrowFunctionFormalParameters(
   }
 
   DeclareFormalParameters(parameters);
-  DCHECK_EQ(parameters->is_simple, parameters->scope->has_simple_parameters());
+  DCHECK_IMPLIES(parameters->is_simple,
+                 parameters->scope->has_simple_parameters());
 }
 
 void Parser::PrepareGeneratorVariables() {

src/parsing/parser.h

@@ -862,7 +862,6 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
   V8_INLINE VariableProxy* ExpressionFromIdentifier(
       const AstRawString* name, int start_position,
       InferName infer = InferName::kYes) {
-    if (has_error()) return nullptr;
     if (infer == InferName::kYes) {
       fni_.PushVariableName(name);
     }