Add support for :void_context as regexp argument to Warning.ignore

CHANGELOG

@@ -1,5 +1,7 @@
 === master
 
+* Add support for :void_context as regexp argument to Warning.ignore (jeremyevans)
+
 * Support :category keyword to Warning.warn on Ruby 3.0 (jeremyevans)
 
 * Fix :taint warning handling on Ruby 3.0 (jeremyevans)

README.rdoc

@@ -42,6 +42,7 @@ appropriate regexp.  The supported symbols are:
 * :taint
 * :unused_var
 * :useless_operator
+* :void_context
 
 <tt>Warning.process</tt> takes an optional path prefix and a block, and if the
 warning string starts with the path prefix, it calls the block with the warning

lib/warning.rb

@@ -19,6 +19,7 @@ module Processor
       safe: /: warning: (?:rb_safe_level_2_warning|rb_safe_level|rb_set_safe_level_force|rb_set_safe_level|rb_secure|rb_insecure_operation|rb_check_safe_obj|\$SAFE) will (?:be removed|become a normal global variable) in Ruby 3\.0\n\z/,
       taint: /: warning: (?:rb_error_untrusted|rb_check_trusted|Pathname#taint|Pathname#untaint|rb_env_path_tainted|Object#tainted\?|Object#taint|Object#untaint|Object#untrusted\?|Object#untrust|Object#trust|rb_obj_infect|rb_tainted_str_new|rb_tainted_str_new_cstr) is deprecated and will be removed in Ruby 3\.2\.?\n\z/,
       mismatched_indentations: /: warning: mismatched indentations at '.+' with '.+' at \d+\n\z/,
+      void_context: /possibly useless use of :: in void context/,
     }
 
     # Map of action symbols to procs that return the symbol
@@ -75,6 +76,8 @@ def freeze
     # :unused_var :: Ignore warnings for unused variables.
     # :useless_operator :: Ignore warnings when using operators such as == and > when the
     #                      result is not used.
+    # :void_context :: Ignore warnings for :: to reference constants when the result is not
+    #                  used (often used to trigger autoload).
     #
     # Examples:
     #

test/test_warning.rb

@@ -178,6 +178,18 @@ def test_warning_ignore_bignum
     end
   end
 
+  def test_warning_ignore_void_context
+    assert_warning(/warning: possibly useless use of :: in void context/) do
+      instance_eval('::Object; nil', __FILE__, __LINE__)
+    end
+
+    Warning.ignore(:void_context, __FILE__)
+
+    assert_warning '' do
+      instance_eval('::Object; nil', __FILE__, __LINE__)
+    end
+  end
+
   def test_warning_ignore_ambiguous_slash
     def self.d(re); end
     assert_warning(/warning: ambi/) do