On 2016-10-20 17:17, Stefan Monnier wrote:
>> -;;; cc-mode-tests.el --- Test suite for cc-mode.  -*- lexical-binning: t -*-
>> +;;; cc-mode-tests.el --- Test suite for cc-mode.  -*- lexical-binding: t; -*-
> 
> AFAIK both forms are correct and should work just fine.

The actual change was lexical-binning → lexical-binding, not the semi-colon, I think :)