This switches most error printing to use diagnostics instead of direct
stream writes, even when not a specific file diagnostic. I'm allowing
empty filenames for this use-case.
This allows a little more specific testing to validate coverage of
output using the diagnostic coverage test. I'm adding a few tests to
cover things that weren't previously tested.
Separately, this also forces a little more standardization in format...
considering how changes like #4568 show effort being spent to _mirror_
diagnostic style, my thought is now to just use diagnostic code where
possible.
Note this also allows incrementally better testing of the language
server; I'm changing the crash fix from #4847 in favor of diagnostic
testing.
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Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
One of the things that ClangRunnerTest is doing is capturing
stderr/stdout because clang prints to it directly. This adds support for
that to FileTest.
I'm renaming the current `capture_output` field to `dump_output` because
the name is ambiguous after this change, and the flag is already named
`--dump_output`. It's still not great, but at least it's more distinct.
Note ClangRunner still doesn't use the vfs; that still needs work. I'm
just moving the NoArgs test over as a trivial test of the functionality.
Jon Ross-PerkinsandChandler Carruth