[C++ Patch] PR 44516

[Jason Merrill]

On 05/16/2012 01:15 PM, Manuel López-Ibáñez wrote:
> My proposal is to assert when checking is enabled (gcc_checking_assert
> instead of gcc_assert) and degrade gracefully when not (use
> input_location if given an UNKNOWN_LOCATION).

That makes sense if we want to require the front end to move to explicit 
locations everywhere at once, but prevents a gradual transition. 
Currently diagnostics just use input_location.  Paolo's patch passes in 
explicit locations to a bunch of functions, so now we can use those in 
diagnostics.  But if for some reason we pass UNKNOWN_LOCATION in because 
some part of the compiler hasn't been updated yet, we get an ICE instead 
of the merely inaccurate location we had before.

Jason