996225 - gcc 4.9 build error: ScopeObject.h:907:39: error: specialization of 'bool JSObject::is() const [with T = js::StaticBlockObject]' after instantiation

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[Daniel Holbert [:dholbert]]

STR:
 1. Install a GCC 4.9 snapshot.*
 2. Try to compile mozilla-central.

ACTUAL RESULTS: Several instances of this build error:
{
js/src/vm/ScopeObject.h:907:39: error: specialization of 'bool JSObject::is() const [with T = js::StaticBlockObject]' after instantiation
}

EXPECTED RESULTS: No build error.


Source reference: http://mxr.mozilla.org/mozilla-central/source/js/src/vm/ScopeObject.h?rev=539b1a125f71&mark=912-917#912

NOTE: If I delete this function definition (the highlighted region in the MXR link above), then I can build js/src successfully (no other errors there).


*One way to get gcc 4.9: Install Ubuntu 14.04 (currently in final beta), and 'sudo apt-get install gcc-snapshot', and add this to your .mozconfig:
export CC=/usr/lib/gcc-snapshot/bin/gcc
export CXX=/usr/lib/gcc-snapshot/bin/g++

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: strawman hackaround: drop the function that GCC complains about

Just for the sake of illustration (and to aid anyone else trying to build w/ GCC 4.9), here's a hackaround that drops this function, which lets me get past this build error.

Comment 2

[Steve Fink [:sfink] [:s:]]

I'm assuming this problem is long gone now? (At least, I've been compiling with gcc 4.9.1.)

Comment 3

[Daniel Holbert [:dholbert]]

I've been using clang recently, but I'm pretty sure I've successfully compiled with GCC 4.9 at some point since this bug was filed.

So, I think this is WFM (particularly given that you can build w/ gcc 4.9.1)