On Thu, Jan 09, 2025 at 12:05:43PM -0500, Patrick Palka wrote: > On Wed, 8 Jan 2025, Jason Merrill wrote: > > > On 12/21/24 11:35 AM, Simon Martin wrote: > > > When erroring out due to an incomplete type, we add a contextual note > > > about the type. However, when the error is suppressed by > > > -Wno-template-body, the note remains, making the compiler output quite > > > puzzling. > > > > > > This patch makes sure the note is suppressed if we're processing a > > > template declaration body with -Wno-template-body. > > > > > > Successfully tested on x86_64-pc-linux-gnu. > > > > > > PR c++/118163 > > > > > > gcc/cp/ChangeLog: > > > > > > * cp-tree.h (get_current_template): Declare. > > > * error.cc (get_current_template): Make non static. > > > * typeck2.cc (cxx_incomplete_type_inform): Suppress note when > > > parsing a template declaration with -Wno-template-body. > > > > I think rather than adding this sort of thing in lots of places where an > > error > > is followed by an inform, we should change error to return bool like other > > diagnostic functions, and check its return value before calling > > cxx_incomplete_type_inform or plain inform. This likely involves the same > > number of changes, but they should be smaller. > > > > Patrick, what do you think? > > That makes sense to me, it's consistent with the 'warning' API and how > we handle issuing a warning followed by a note. But since the > -Wtemplate-body mechanism is really only useful for compiling legacy > code where you don't really care about any diagnostics anyway, and > the intended way to use it is -fpermissive / -Wno-error=template-body > rather than -Wno-template-body, I'd prefer a less invasive solution that > doesn't change the API of 'error' if possible. > > I wonder if we can work around this by taking advantage of the fact that > notes that follow an error are expected to be linked via an active > auto_diagnostic_group? Roughly, if we issued a -Wtemplate-body > diagnostic from an active auto_diagnostic_group then all other > diagnostics from that auto_diagnostic_group should also be associated > with -Wtemplate-body, including notes. That way -Wno-template-body will > effectively suppress subsequent notes followed by an eligible error, and > no 'error' callers need to be changed (unless to use > auto_diagnostic_group).
FWIW, I love this auto_diagnostic_group idea. Marek
