At the time, JsAccount had to use the nonstandard __FUNCTION__ predefined macro as part of its mechanism to know which functions were being overridden. In particular, the macro has a different value in Visual Studio than in gcc or clang, but JsAccount had an #ifdef to accommodate for the difference. Unfortunately clang-cl emulates the macros used to detect regular cl, so JsAccount thinks that clang-cl is Visual Studio and so its assumption of the value of the __FUNCTION__ macro is no longer correct. Fortunately (as mentioned in the comments) the standard __func__ value has been available since Visual Studio 2015 anyway.

Try run: https://treeherder.mozilla.org/#/jobs?repo=try-comm-central&revision=7abe5e48aaa67d74ef32ab289a905aa804f196c8 (Sorry, but after getting my fingers burned on 1492889, I'm wary of trimming the number of Try builds right now.)

Comment on attachment 9016466 [details] [diff] [review] Proposed patch > /// Method name to delegate to JavaScript. >- void add(in string aMethod); >+ void add(in ACString aMethod); This is to allow the simplification of the C++ implementation, which can now pass its parameter directly through to the hashtable. >+ mMethods.Put(aMethodName, true); (By the way I've tried this locally on both Win32 and Linux64 so I know that the code works.)

Comment on attachment 9016466 [details] [diff] [review] Proposed patch Wow, and you've also fixed the mystery of bug 1475166 where a test started to fail when switching to clang-cl. I'll re-enable that now, thanks!!

Oh, wow, take 2, a proper patch with HG header ;-)

Pushed by mozilla@jorgk.com: https://hg.mozilla.org/comm-central/rev/e4fff573e9c7 Switch from __FUNCTION__ to the standard __func__ to unbreak JsAccount on clang-cl builds. r=jorgk