diff --git a/lib/mutant/expression/namespace.rb b/lib/mutant/expression/namespace.rb
index 828d9de7..05d6cb36 100644
--- a/lib/mutant/expression/namespace.rb
+++ b/lib/mutant/expression/namespace.rb
@@ -61,7 +61,7 @@ module Mutant
         # @api private
         #
         def namespace
-          match[__method__] || ''
+          match[__method__] || EMPTY_STRING
         end
 
       end # Recursive
diff --git a/lib/mutant/mutator/node/named_value/variable_assignment.rb b/lib/mutant/mutator/node/named_value/variable_assignment.rb
index 13760d95..406bad04 100644
--- a/lib/mutant/mutator/node/named_value/variable_assignment.rb
+++ b/lib/mutant/mutator/node/named_value/variable_assignment.rb
@@ -12,7 +12,7 @@ module Mutant
             gvasgn: '$',
             cvasgn: '@@',
             ivasgn: '@',
-            lvasgn: ''
+            lvasgn: EMPTY_STRING
           }
 
           MAP = IceNine.deep_freeze(