Turn ZoneList inner_scopes into a linked list

test/cctest/test-parsing.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1076 matching lines @@
       i::ParseInfo info(&zone, script);
       i::Parser parser(&info);
       info.set_global();
       CHECK(parser.Parse(&info));
       CHECK(i::Rewriter::Rewrite(&info));
       CHECK(i::Scope::Analyze(&info));
       CHECK(info.literal() != NULL);
 
       i::Scope* script_scope = info.literal()->scope();
       CHECK(script_scope->is_script_scope());
-      CHECK_EQ(1, script_scope->inner_scopes()->length());
 
-      i::Scope* scope = script_scope->inner_scopes()->at(0);
+      i::Scope* scope = script_scope->inner_scope();
+      DCHECK_NOT_NULL(scope);
+      DCHECK_NULL(scope->sibling());
       // Adjust for constructor scope.
       if (j == 2) {
-        CHECK_EQ(1, scope->inner_scopes()->length());
-        scope = scope->inner_scopes()->at(0);
+        scope = scope->inner_scope();
+        DCHECK_NOT_NULL(scope);
+        DCHECK_NULL(scope->sibling());
       }
       CHECK_EQ((source_data[i].expected & ARGUMENTS) != 0,
                scope->uses_arguments());
       CHECK_EQ((source_data[i].expected & SUPER_PROPERTY) != 0,
                scope->uses_super_property());
       if ((source_data[i].expected & THIS) != 0) {
         // Currently the is_used() flag is conservative; all variables in a
         // script scope are marked as used.
         CHECK(
             scope->Lookup(info.ast_value_factory()->this_string())->is_used());
@@ skipping 291 matching lines @@
     info.set_global();
     info.set_language_mode(source_data[i].language_mode);
     parser.Parse(&info);
     CHECK(info.literal() != NULL);
 
     // Check scope types and positions.
     i::Scope* scope = info.literal()->scope();
     CHECK(scope->is_script_scope());
     CHECK_EQ(scope->start_position(), 0);
     CHECK_EQ(scope->end_position(), kProgramSize);
-    CHECK_EQ(scope->inner_scopes()->length(), 1);
 
-    i::Scope* inner_scope = scope->inner_scopes()->at(0);
+    i::Scope* inner_scope = scope->inner_scope();
+    DCHECK_NOT_NULL(inner_scope);
+    DCHECK_NULL(inner_scope->sibling());
     CHECK_EQ(inner_scope->scope_type(), source_data[i].scope_type);
     CHECK_EQ(inner_scope->start_position(), kPrefixLen);
     // The end position of a token is one position after the last
     // character belonging to that token.
     CHECK_EQ(inner_scope->end_position(), kPrefixLen + kInnerLen);
   }
 }
 
 
 TEST(DiscardFunctionBody) {
@@ skipping 2115 matching lines @@
 
           i::Handle<i::Script> script = factory->NewScript(source);
           i::Zone zone(CcTest::i_isolate()->allocator());
           i::ParseInfo info(&zone, script);
           i::Parser parser(&info);
           CHECK(parser.Parse(&info));
           CHECK(i::Compiler::Analyze(&info));
           CHECK(info.literal() != NULL);
 
           i::Scope* scope = info.literal()->scope();
-          CHECK_EQ(scope->inner_scopes()->length(), 1);
-          i::Scope* inner_scope = scope->inner_scopes()->at(0);
+          i::Scope* inner_scope = scope->inner_scope();
+          DCHECK_NOT_NULL(inner_scope);
+          DCHECK_NULL(inner_scope->sibling());
           const i::AstRawString* var_name =
               info.ast_value_factory()->GetOneByteString("x");
           i::Variable* var = inner_scope->Lookup(var_name);
           bool expected = outers[i].assigned || inners[j].assigned;
           CHECK(var != NULL);
           CHECK(var->is_used() || !expected);
           CHECK((var->maybe_assigned() == i::kMaybeAssigned) == expected);
         }
       }
     }
@@ skipping 4386 matching lines @@
     "(a,);",
     "(a,b,c,);",
     NULL
   };
   // clang-format on
 
   static const ParserFlag always_flags[] = {kAllowHarmonyTrailingCommas};
   RunParserSyncTest(context_data, data, kError, NULL, 0, always_flags,
                     arraysize(always_flags));
 }