Suggest global variables

I don't know how to make it work with Ractor.

Author: styd

lib/did_you_mean/spell_checkers/name_error_checkers/variable_name_checker.rb

@@ -4,7 +4,7 @@
 
 module DidYouMean
   class VariableNameChecker
-    attr_reader :name, :method_names, :lvar_names, :ivar_names, :cvar_names
+    attr_reader :name, :method_names, :gvar_names, :lvar_names, :ivar_names, :cvar_names
 
     NAMES_TO_EXCLUDE = { 'foo' => [:fork, :for] }
     NAMES_TO_EXCLUDE.default = []
@@ -67,6 +67,7 @@ class VariableNameChecker
 
     def initialize(exception)
       @name       = exception.name.to_s.tr("@", "")
+      @gvar_names = defined?(Ractor) ? [] : global_variables.select {|g| g[/\$[A-Za-z]/] }
       @lvar_names = exception.respond_to?(:local_variables) ? exception.local_variables : []
       receiver    = exception.receiver
 
@@ -78,7 +79,7 @@ def initialize(exception)
 
     def corrections
       @corrections ||= SpellChecker
-                     .new(dictionary: (RB_RESERVED_WORDS + lvar_names + method_names + ivar_names + cvar_names))
+                     .new(dictionary: (RB_RESERVED_WORDS + gvar_names + lvar_names + method_names + ivar_names + cvar_names))
                      .correct(name).uniq - NAMES_TO_EXCLUDE[@name]
     end
   end

test/spell_checking/test_variable_name_check.rb

@@ -51,6 +51,15 @@ def test_corrections_include_method_from_module
     assert_match "Did you mean?  from_module", get_message(error)
   end
 
+  def test_corrections_include_global_variable_name
+    return if defined?(Ractor)
+
+    error = assert_raise(NameError) { stin }
+
+    assert_correction :$stdin, error.corrections
+    assert_match "Did you mean?  $stdin", get_message(error)
+  end
+
   def test_corrections_include_local_variable_name
     if RUBY_ENGINE != "jruby"
       person = person = nil