857740 - GCC 4.8 build warning: convolver.h:76:55: warning: typedef 'fixed_type_should_fit_in_float_mantissa' locally defined but not used [-Wunused-local-typedefs]

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Daniel Holbert [:dholbert]]

GCC 4.8 warns for an unused typedef from an under-the-hood typedef in a COMPILE_ASSERT used in gfx/2d/convolver.h:
{
gfx/2d/convolver.h:76:55: warning: typedef 'fixed_type_should_fit_in_float_mantissa' locally defined but not used [-Wunused-local-typedefs]
     COMPILE_ASSERT(sizeof(Fixed) == 2, fixed_type_should_fit_in_float_mantissa);
}

As we did in bug 851237 (which fixed another chunk of these warnings), we might as well just use MOZ_STATIC_ASSERT here.  It's got a typedef under the hood too, but it has annotations to tell the compiler that the unused typedef is OK. (added in "patch 1" on bug 851237)

(Alternately, we could fix this by adding some boilerplate to COMPILE_ASSERT like we did for MOZ_STATIC_ASSERT, but that's a bit more work (particularly for a macro that's defined in a third-party header).  Better to just consistently use our own known-good static-assertion macro where possible, IMHO.)

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: fix v1: use MOZ_STATIC_ASSERT

Comment 2

[Daniel Holbert [:dholbert]]

[adding dependency on bug 486918, which is where we imported this header]

Comment 3

[Daniel Holbert [:dholbert]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a451409c4d94

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/a451409c4d94