Remove useless mutations and fix index reference

Changelog.md

@@ -1,3 +1,8 @@
+# v0.5.20 2014-06-xx
+
+* Remove a bunch of useless mutations to nil.something
+* Readd mutation of index reference arguments
+
 # v0.5.20 2014-06-15
 
 * Remove support for matchers prefixed with ::

lib/mutant/mutator/node/send.rb

@@ -36,8 +36,6 @@ module Mutant
         def dispatch
           emit_singletons
           case selector
-          when INDEX_REFERENCE
-            run(Index::Reference)
           when INDEX_ASSIGN
             run(Index::Assign)
           else
@@ -160,7 +158,9 @@ module Mutant
         def mutate_receiver
           return unless receiver
           emit_implicit_self
-          emit_receiver_mutations
+          emit_receiver_mutations do |node|
+            !n_nil?(node)
+          end
         end
 
         # Emit implicit self mutation
@@ -210,4 +210,5 @@ module Mutant
       end # Send
     end # Node
   end # Mutator
+
 end # Mutant

lib/mutant/mutator/node/send/attribute_assignment.rb

@@ -2,8 +2,7 @@ module Mutant
   class Mutator
     class Node
       class Send
-
-        # Mutator for sends that correspond to an attribute assignment
+        # Mutator for attribute assignments
         class AttributeAssignment < self
 
         private
@@ -42,7 +41,6 @@ module Mutant
           end
 
         end # AttributeAssignment
-
       end # Send
     end # Node
   end # Mutator

lib/mutant/mutator/node/send/index.rb

@@ -7,21 +7,6 @@ module Mutant
         # Base mutator for index operations
         class Index < self
 
-          # Mutator for index references
-          class Reference < self
-
-            # Perform dispatch
-            #
-            # @return [undefined]
-            #
-            # @api private
-            #
-            def dispatch
-              emit(receiver)
-            end
-
-          end # Reference
-
           # Mutator for index assignments
           class Assign < self
 

meta/op_assgn.rb

@@ -9,7 +9,6 @@ Mutant::Meta::Example.add do
   mutation '@a.b += 0'
   mutation '@a.b += nil'
   mutation '@a.b += self'
-  mutation 'nil.b += 1'
   mutation 'self.b += 1'
   # TODO: fix invalid AST
   #   This should not get emitted as invalid AST with valid unparsed source

meta/regex.rb

@@ -15,7 +15,6 @@ Mutant::Meta::Example.add do
   mutation '//' # match all
   mutation '/#{foo}n/'
   mutation '/a\A/'         # match nothing
-  mutation '/#{nil.bar}n/'
   mutation '/#{self.bar}n/'
   mutation '/#{nil}n/'
   mutation '/#{self}n/'

meta/send.rb

@@ -49,7 +49,6 @@ Mutant::Meta::Example.add do
   mutation 'foo.gsub(a, self)'
   mutation 'foo.gsub(nil, b)'
   mutation 'foo.gsub(self, b)'
-  mutation 'nil.gsub(a, b)'
   mutation 'self.gsub(a, b)'
 end
 
@@ -64,7 +63,6 @@ Mutant::Meta::Example.add do
   mutation 'self.send(bar)'
   mutation 'foo.send(nil)'
   mutation 'foo.send(self)'
-  mutation 'nil.send(bar)'
 end
 
 Mutant::Meta::Example.add do
@@ -76,7 +74,6 @@ Mutant::Meta::Example.add do
   mutation 'self.bar'
   mutation 'baz'
   # This one could probably be removed
-  mutation 'nil.bar=baz'
 end
 
 Mutant::Meta::Example.add do
@@ -90,7 +87,6 @@ Mutant::Meta::Example.add do
   mutation 'foo.bar'
   mutation 'baz'
   # This one could probably be removed
-  mutation 'nil.bar = baz'
 end
 
 Mutant::Meta::Example.add do
@@ -119,13 +115,6 @@ Mutant::Meta::Example.add do
   mutation 'foo'
 end
 
-Mutant::Meta::Example.add do
-  source 'foo[*bar]'
-
-  singleton_mutations
-  mutation 'foo'
-end
-
 Mutant::Meta::Example.add do
   source 'foo'
 
@@ -137,7 +126,6 @@ Mutant::Meta::Example.add do
 
   singleton_mutations
   mutation 'foo'
-  mutation 'nil.foo'
 end
 
 Unparser::Constants::KEYWORDS.each do |keyword|
@@ -145,7 +133,6 @@ Unparser::Constants::KEYWORDS.each do |keyword|
     source "self.#{keyword}"
 
     singleton_mutations
-    mutation "nil.#{keyword}"
   end
 end
 
@@ -154,7 +141,6 @@ Mutant::Meta::Example.add do
 
   singleton_mutations
   mutation 'foo'
-  mutation 'nil.bar'
   mutation 'self.bar'
 end
 
@@ -164,8 +150,6 @@ Mutant::Meta::Example.add do
   singleton_mutations
   mutation 'self.class'
   mutation 'self.foo'
-  mutation 'nil.class.foo'
-  mutation 'nil.foo'
 end
 
 Mutant::Meta::Example.add do
@@ -181,7 +165,6 @@ Mutant::Meta::Example.add do
   singleton_mutations
   mutation 'self.foo'
   mutation 'foo(nil)'
-  mutation 'nil.foo(nil)'
 end
 
 Unparser::Constants::KEYWORDS.each do |keyword|
@@ -192,7 +175,6 @@ Unparser::Constants::KEYWORDS.each do |keyword|
     mutation "self.#{keyword}(nil)"
     mutation "foo.#{keyword}"
     mutation 'foo'
-    mutation "nil.#{keyword}(nil)"
   end
 end
 
@@ -222,6 +204,44 @@ Mutant::Meta::Example.add do
   mutation 'self / foo'
 end
 
+Mutant::Meta::Example.add do
+  source 'foo[1]'
+
+  singleton_mutations
+  mutation '1'
+  mutation 'foo'
+  mutation 'foo[]'
+  mutation 'self[1]'
+  mutation 'foo[0]'
+  mutation 'foo[2]'
+  mutation 'foo[-1]'
+  mutation 'foo[nil]'
+  mutation 'foo[self]'
+end
+
+Mutant::Meta::Example.add do
+  source 'self.foo[]'
+
+  singleton_mutations
+  mutation 'self.foo'
+  mutation 'self[]'
+  mutation 'foo[]'
+end
+
+Mutant::Meta::Example.add do
+  source 'foo[*bar]'
+
+  singleton_mutations
+  mutation 'foo'
+  mutation 'foo[]'
+  mutation 'foo[nil]'
+  mutation 'foo[self]'
+  mutation 'foo[bar]'
+  mutation 'foo[*self]'
+  mutation 'foo[*nil]'
+  mutation 'self[*bar]'
+end
+
 (Mutant::BINARY_METHOD_OPERATORS - [:==, :eql?]).each do |operator|
   Mutant::Meta::Example.add do
     source "true #{operator} false"