[cleanup] Remove on-by-default --harmony-trailing-commas flag

This feature has been on by default without incident
since V8 5.8.

Bug: v8:5051
Change-Id: I1baf81922efd87e07448955147c50a5ba5a0aa42
Reviewed-on: https://chromium-review.googlesource.com/532214Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45881}

src/bootstrapper.cc

@@ -3922,7 +3922,6 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_regexp_property)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_function_sent)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tailcalls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_restrictive_generators)
-EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_trailing_commas)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_function_tostring)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_class_fields)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_object_rest_spread)

src/flag-definitions.h

@@ -219,8 +219,6 @@ DEFINE_IMPLICATION(es_staging, harmony)
 #define HARMONY_SHIPPING_BASE(V)                           \
   V(harmony_restrictive_generators,                        \
     "harmony restrictions on generator declarations")      \
-  V(harmony_trailing_commas,                               \
-    "harmony trailing commas in function parameter lists") \
   V(harmony_object_rest_spread, "harmony object rest spread properties")
 
 #ifdef V8_INTL_SUPPORT

src/parsing/parser-base.h

@@ -265,7 +265,6 @@ class ParserBase {
         allow_harmony_do_expressions_(false),
         allow_harmony_function_sent_(false),
         allow_harmony_restrictive_generators_(false),
-        allow_harmony_trailing_commas_(false),
         allow_harmony_class_fields_(false),
         allow_harmony_object_rest_spread_(false),
         allow_harmony_dynamic_import_(false),
@@ -281,7 +280,6 @@ class ParserBase {
   ALLOW_ACCESSORS(harmony_do_expressions);
   ALLOW_ACCESSORS(harmony_function_sent);
   ALLOW_ACCESSORS(harmony_restrictive_generators);
-  ALLOW_ACCESSORS(harmony_trailing_commas);
   ALLOW_ACCESSORS(harmony_class_fields);
   ALLOW_ACCESSORS(harmony_object_rest_spread);
   ALLOW_ACCESSORS(harmony_dynamic_import);
@@ -1570,7 +1568,6 @@ class ParserBase {
   bool allow_harmony_do_expressions_;
   bool allow_harmony_function_sent_;
   bool allow_harmony_restrictive_generators_;
-  bool allow_harmony_trailing_commas_;
   bool allow_harmony_class_fields_;
   bool allow_harmony_object_rest_spread_;
   bool allow_harmony_dynamic_import_;
@@ -2028,8 +2025,7 @@ ParserBase<Impl>::ParseExpressionCoverGrammar(bool accept_IN, bool* ok) {
           scanner()->location(), MessageTemplate::kParamAfterRest);
     }
 
-    if (allow_harmony_trailing_commas() && peek() == Token::RPAREN &&
-        PeekAhead() == Token::ARROW) {
+    if (peek() == Token::RPAREN && PeekAhead() == Token::ARROW) {
       // a trailing comma is allowed at the end of an arrow parameter list
       break;
     }
@@ -2768,7 +2764,7 @@ typename ParserBase<Impl>::ExpressionListT ParserBase<Impl>::ParseArguments(
         classifier()->RecordAsyncArrowFormalParametersError(
             scanner()->location(), MessageTemplate::kParamAfterRest);
       }
-      if (allow_harmony_trailing_commas() && peek() == Token::RPAREN) {
+      if (peek() == Token::RPAREN) {
         // allow trailing comma
         done = true;
       }
@@ -3748,7 +3744,7 @@ void ParserBase<Impl>::ParseFormalParameterList(FormalParametersT* parameters,
         break;
       }
       if (!Check(Token::COMMA)) break;
-      if (allow_harmony_trailing_commas() && peek() == Token::RPAREN) {
+      if (peek() == Token::RPAREN) {
         // allow the trailing comma
         break;
       }

src/parsing/parser.cc

@@ -525,7 +525,6 @@ Parser::Parser(ParseInfo* info)
   set_allow_harmony_do_expressions(FLAG_harmony_do_expressions);
   set_allow_harmony_function_sent(FLAG_harmony_function_sent);
   set_allow_harmony_restrictive_generators(FLAG_harmony_restrictive_generators);
-  set_allow_harmony_trailing_commas(FLAG_harmony_trailing_commas);
   set_allow_harmony_class_fields(FLAG_harmony_class_fields);
   set_allow_harmony_object_rest_spread(FLAG_harmony_object_rest_spread);
   set_allow_harmony_dynamic_import(FLAG_harmony_dynamic_import);

src/parsing/parser.h

@@ -294,7 +294,6 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
       SET_ALLOW(tailcalls);
       SET_ALLOW(harmony_do_expressions);
       SET_ALLOW(harmony_function_sent);
-      SET_ALLOW(harmony_trailing_commas);
       SET_ALLOW(harmony_class_fields);
       SET_ALLOW(harmony_object_rest_spread);
       SET_ALLOW(harmony_dynamic_import);

test/cctest/test-parsing.cc

@@ -1269,7 +1269,6 @@ enum ParserFlag {
   kAllowNatives,
   kAllowHarmonyFunctionSent,
   kAllowHarmonyRestrictiveGenerators,
-  kAllowHarmonyTrailingCommas,
   kAllowHarmonyClassFields,
   kAllowHarmonyObjectRestSpread,
   kAllowHarmonyDynamicImport,
@@ -1288,7 +1287,6 @@ void SetGlobalFlags(i::EnumSet<ParserFlag> flags) {
   i::FLAG_harmony_function_sent = flags.Contains(kAllowHarmonyFunctionSent);
   i::FLAG_harmony_restrictive_generators =
       flags.Contains(kAllowHarmonyRestrictiveGenerators);
-  i::FLAG_harmony_trailing_commas = flags.Contains(kAllowHarmonyTrailingCommas);
   i::FLAG_harmony_class_fields = flags.Contains(kAllowHarmonyClassFields);
   i::FLAG_harmony_object_rest_spread =
       flags.Contains(kAllowHarmonyObjectRestSpread);
@@ -1304,8 +1302,6 @@ void SetParserFlags(i::PreParser* parser, i::EnumSet<ParserFlag> flags) {
       flags.Contains(kAllowHarmonyFunctionSent));
   parser->set_allow_harmony_restrictive_generators(
       flags.Contains(kAllowHarmonyRestrictiveGenerators));
-  parser->set_allow_harmony_trailing_commas(
-      flags.Contains(kAllowHarmonyTrailingCommas));
   parser->set_allow_harmony_class_fields(
       flags.Contains(kAllowHarmonyClassFields));
   parser->set_allow_harmony_object_rest_spread(
@@ -9230,9 +9226,7 @@ TEST(TrailingCommasInParameters) {
   };
   // clang-format on
 
-  static const ParserFlag always_flags[] = {kAllowHarmonyTrailingCommas};
-  RunParserSyncTest(context_data, data, kSuccess, NULL, 0, always_flags,
-                    arraysize(always_flags));
+  RunParserSyncTest(context_data, data, kSuccess);
 }
 
 TEST(TrailingCommasInParametersErrors) {
@@ -9295,9 +9289,7 @@ TEST(TrailingCommasInParametersErrors) {
   };
   // clang-format on
 
-  static const ParserFlag always_flags[] = {kAllowHarmonyTrailingCommas};
-  RunParserSyncTest(context_data, data, kError, NULL, 0, always_flags,
-                    arraysize(always_flags));
+  RunParserSyncTest(context_data, data, kError);
 }
 
 TEST(ArgumentsRedeclaration) {

test/mjsunit/harmony/trailing-commas-length.js

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-trailing-commas
-
 function f1(a,) {}
 function f2(a,b,) {}
 function f3(a,b,c,) {}