Fix ls on Fixnum [Fixes #1120]

lib/pry/commands/ls/interrogateable.rb

@@ -10,9 +10,8 @@ module Pry::Command::Ls::Interrogateable
     if interrogating_a_module?
       @interrogatee
     else
-      class << @interrogatee
+      singleton = Pry::Method.singleton_class_of(@interrogatee)
-        ancestors.grep(::Class).reject { |c| c == self }.first
+      singleton.ancestors.grep(::Class).reject { |c| c == singleton }.first
-      end
     end
   end
 

lib/pry/method.rb

@@ -192,8 +192,6 @@ class Pry
         /^define_method\(?\s*[:\"\']#{Regexp.escape(name)}|^def\s*#{Regexp.escape(name)}/ =~ definition_line.strip
       end
 
-      private
-
       # Get the singleton classes of superclasses that could define methods on
       # the given class object, and any modules they include.
       # If a module is included at multiple points in the ancestry, only
@@ -207,7 +205,13 @@ class Pry
         resolution_order.reverse.uniq.reverse - Class.included_modules
       end
 
-      def singleton_class_of(obj); class << obj; self; end end
+      def singleton_class_of(obj)
+        begin
+          class << obj; self; end
+        rescue TypeError # can't define singleton. Fixnum, Symbol, Float, ...
+          obj.class
+        end
+      end
     end
 
     # A new instance of `Pry::Method` wrapping the given `::Method`, `UnboundMethod`, or `Proc`.

spec/commands/ls_spec.rb

@@ -47,6 +47,12 @@ describe "ls" do
     end
   end
 
+  describe "immediates" do
+    it "should work on Fixnum" do
+      pry_eval("ls 5").should =~ /Fixnum#methods:.*modulo/m
+    end
+  end
+
   describe "methods" do
     it "should show public methods by default" do
       output = pry_eval("ls Class.new{ def goo; end; public :goo }.new")