fixes #1420: (fn() ->) by causing the Lexer::tagParameters method to

give up looking for a parameter list when it saw a `CALL_START` token.

lib/lexer.js

@@ -444,6 +444,8 @@
             } else if (tok[0] === '(') {
               tok[0] = 'PARAM_START';
               return this;
+            } else {
+              return this;
             }
         }
       }

src/lexer.coffee

@@ -378,6 +378,7 @@ exports.Lexer = class Lexer
           else if tok[0] is '('
             tok[0] = 'PARAM_START'
             return this
+          else return this
     this
 
   # Close up all remaining open blocks at the end of the file.