Apply modifications by @jwalton

src/coffee-script.coffee

@@ -210,15 +210,8 @@ patchStackTrace = ->
 
     getSourceMapping = (filename, line, column) ->
       sourceMap = mainModule._sourceMaps[filename]
-      answer = sourceMap.getSourcePosition [line - 1, column] if sourceMap
-      if answer
-        answer[0] += 1
-        # # un-comment to dirty patch the column number, not very accurate
-        # if answer[1] > 3
-        #   answer[1] -= 3
-        # else
-        #   answer[1] = 0
-      answer
+      answer = sourceMap.getSourcePosition [line-1, column-1] if sourceMap
+      if answer then [answer[0]+1, answer[1]+1] else null
 
     frames = for frame in stack
       break if frame.getFunction() is exports.run