define a Pry::Method#source_location, fixes #524

* This fixes _file_ for rbx core methods by special casing rbx right at Pry::Method#source_location, as a result
most things down stream should 'just work' with rbx, with no other checks required

lib/pry/method.rb

@@ -250,8 +250,8 @@ class Pry
             code = strip_comments_from_c_code(info.source)
           end
         when :ruby
-          if Helpers::BaseHelpers.rbx? && core?
-            code = core_code
+          if Helpers::BaseHelpers.rbx? && !pry_method?
+             code = core_code
           elsif pry_method?
             code = Pry.new(:input => StringIO.new(Pry.line_buffer[source_line..-1].join), :prompt => proc {""}, :hooks => Pry::Hooks.new).r
           else
@@ -270,8 +270,8 @@ class Pry
           info = pry_doc_info
           info.docstring if info
         when :ruby
-          if Helpers::BaseHelpers.rbx? && core?
-            strip_leading_hash_and_whitespace_from_ruby_comments(core_doc)
+           if Helpers::BaseHelpers.rbx? && !pry_method?
+             strip_leading_hash_and_whitespace_from_ruby_comments(core_doc)
           elsif pry_method?
             raise CommandError, "Can't view doc for a REPL-defined method."
           else
@@ -286,6 +286,15 @@ class Pry
       source_location.nil? ? :c : :ruby
     end
 
+    def source_location
+      if Helpers::BaseHelpers.rbx?
+        file, line = @method.source_location
+        [RbxPath.convert_path_to_full(file), line]
+      else
+        @method.source_location
+      end
+    end
+
     # @return [String, nil] The name of the file the method is defined in, or
     #   `nil` if the filename is unavailable.
     def source_file

lib/pry/rbx_method.rb

@@ -1,20 +1,13 @@
 class Pry
   module RbxMethod
     private
-    def core?
-      source_file and RbxPath.is_core_path?(source_file)
-    end
 
     def core_code
-      MethodSource.source_helper(core_path_line)
+      MethodSource.source_helper(source_location)
     end
 
     def core_doc
-      MethodSource.comment_helper(core_path_line)
-    end
-
-    def core_path_line
-      [RbxPath.convert_path_to_full(source_file), source_line]
+      MethodSource.comment_helper(source_location)
     end
   end
 end