meta/op_assgn.rb in mutant-0.5.18 vs meta/op_assgn.rb in mutant-0.5.19

@@ -1,15 +1,17 @@
 # encoding: utf-8
 
 Mutant::Meta::Example.add do
   source '@a.b += 1'
 
+  singleton_mutations
   mutation '@a.b += -1'
   mutation '@a.b += 2'
   mutation '@a.b += 0'
   mutation '@a.b += nil'
+  mutation '@a.b += self'
   mutation 'nil.b += 1'
-  mutation 'nil'
+  mutation 'self.b += 1'
   # TODO: fix invalid AST
   #   This should not get emitted as invalid AST with valid unparsed source
   mutation s(:op_asgn, s(:ivar, :@a), :+, s(:int, 1))
 end