+ ruby33.y: reject invalid gvar as symbol (#974)

This commit tracks upstream commit ruby/ruby@8980207.

lib/parser/lexer.rl

@@ -1387,7 +1387,13 @@ class Parser::Lexer
       ':' ( bareword | global_var | class_var | instance_var |
             operator_fname | operator_arithmetic | operator_rest )
       => {
-        emit(:tSYMBOL, tok(@ts + 1), @ts)
+        gvar_name = tok(@ts + 1)
+
+        if @version >= 33 && gvar_name.start_with?('$0') && gvar_name.length > 2
+          diagnostic :error, :gvar_name, { :name => gvar_name }, range(@ts + 1, @te)
+        end
+
+        emit(:tSYMBOL, gvar_name, @ts)
         fnext expr_end; fbreak;
       };
 

lib/parser/messages.rb

@@ -21,6 +21,7 @@ module Parser
     :regexp_options           => 'unknown regexp options: %{options}',
     :cvar_name                => "`%{name}' is not allowed as a class variable name",
     :ivar_name                => "`%{name}' is not allowed as an instance variable name",
+    :gvar_name                => "`%{name}' is not allowed as a global variable name",
     :trailing_in_number       => "trailing `%{character}' in number",
     :empty_numeric            => 'numeric literal without digits',
     :invalid_octal            => 'invalid octal digit',
@@ -72,7 +73,6 @@ module Parser
     :circular_argument_reference  => 'circular argument reference %{var_name}',
     :pm_interp_in_var_name        => 'symbol literal with interpolation is not allowed',
     :lvar_name                    => "`%{name}' is not allowed as a local variable name",
-    :gvar_name                    => '%{name} is not allowed as a global variable name',
     :undefined_lvar               => "no such local variable: `%{name}'",
     :duplicate_variable_name      => 'duplicate variable name %{name}',
     :duplicate_pattern_key        => 'duplicate hash pattern key %{name}',

test/test_parser.rb

@@ -7784,6 +7784,12 @@ def test_numparam_as_symbols
       %q{:@@1},
       %q{ ^^^ location},
       SINCE_2_7)
+
+    assert_diagnoses(
+      [:error, :gvar_name, { :name => '$01234' }],
+      %q{:$01234},
+      %q{ ^^^^^^ location},
+      SINCE_3_3)
   end
 
   def test_csend_inside_lhs_of_masgn__since_27