Remove Inf & NaN mutations for ranges

- Removes NaN ranges. NaN..N and N..NaN are never valid ranges so it seemed prudent to keep
  them from being emitted.
- Removes Inf as a range boundary mutation. The infinite case should be covered incrementally by the +1/-1
  mutations.
- Closes #392

lib/mutant/mutator/node/literal/range.rb

@@ -11,7 +11,7 @@ module Mutant
             erange: :irange
           }.freeze
 
-          children :start, :_end
+          children :lower_bound, :upper_bound
 
           handle(*MAP.keys)
 
@@ -34,23 +34,6 @@ module Mutant
             emit(s(MAP.fetch(node.type), *children))
           end
 
-          # Emit range start mutations
-          #
-          # @return [undefined]
-          def emit_upper_bound_mutations
-            emit__end_mutations
-            emit_type(N_NAN, _end)
-          end
-
-          # Emit start mutations
-          #
-          # @return [undefined]
-          def emit_lower_bound_mutations
-            emit_start_mutations
-            emit_type(start, N_INFINITY)
-            emit_type(start, N_NAN)
-          end
-
         end # Range
       end # Literal
     end # Node

meta/range.rb

@@ -3,9 +3,6 @@ Mutant::Meta::Example.add :irange do
 
   singleton_mutations
   mutation '1...100'
-  mutation '(0.0 / 0.0)..100'
-  mutation '1..(1.0 / 0.0)'
-  mutation '1..(0.0 / 0.0)'
   mutation '-1..100'
   mutation '0..100'
   mutation '2..100'
@@ -25,9 +22,6 @@ Mutant::Meta::Example.add :erange do
 
   singleton_mutations
   mutation '1..100'
-  mutation '(0.0 / 0.0)...100'
-  mutation '1...(1.0 / 0.0)'
-  mutation '1...(0.0 / 0.0)'
   mutation '-1...100'
   mutation '0...100'
   mutation '2...100'

meta/send.rb

@@ -509,14 +509,11 @@ Mutant::Meta::Example.add :send do
   mutation 'foo(n...-1)'
   mutation 'foo(nil..-1)'
   mutation 'foo(self..-1)'
-  mutation 'foo(n..(1.0 / 0.0))'
-  mutation 'foo(n..(0.0 / 0.0))'
   mutation 'foo(n..nil)'
   mutation 'foo(n..self)'
   mutation 'foo(n..0)'
   mutation 'foo(n..1)'
   mutation 'foo(n..-2)'
-  mutation 'foo((0.0 / 0.0)..-1)'
 end
 
 Mutant::Meta::Example.add :send do
@@ -542,9 +539,6 @@ Mutant::Meta::Example.add :send do
   mutation 'foo[n...-2]'
   mutation 'foo[nil..-2]'
   mutation 'foo[self..-2]'
-  mutation 'foo[n..(1.0 / 0.0)]'
-  mutation 'foo[n..(0.0 / 0.0)]'
-  mutation 'foo[(0.0 / 0.0)..-2]'
 end
 
 Mutant::Meta::Example.add :send do
@@ -568,9 +562,6 @@ Mutant::Meta::Example.add :send do
   mutation 'foo[n...-2]'
   mutation 'foo[nil...-1]'
   mutation 'foo[self...-1]'
-  mutation 'foo[n...(1.0 / 0.0)]'
-  mutation 'foo[n...(0.0 / 0.0)]'
-  mutation 'foo[(0.0 / 0.0)...-1]'
 end
 
 Mutant::Meta::Example.add :send do
@@ -594,9 +585,6 @@ Mutant::Meta::Example.add :send do
   mutation 'foo[n...-1]'
   mutation 'foo[nil..-1]'
   mutation 'foo[self..-1]'
-  mutation 'foo[n..(1.0 / 0.0)]'
-  mutation 'foo[n..(0.0 / 0.0)]'
-  mutation 'foo[(0.0 / 0.0)..-1]'
   mutation 'foo.drop(n)'
 end