The purpose of the newline is to make it clearer where a given
diagnostic begins and ends, particularly as the first message of a
diagnostic may not be the error.
This is a trivial code change, but ripples edits through test files.
This handles toolchain failures per-file. The intent is to allow placing
both "success" and "fail" tests in the same file, using splits. However,
this PR only adds support and updates existing tests to continue
passing.
Move handling of mismatched brackets out of the main lexing loop into a
separate pass that is only run if there are mismatched brackets This is
done in preparation for using both lookahead and lookbehind to work out
how to match brackets, and to get this code far away from the hot lexing
loop.
Fix bracket insertion location to be immediately after the token that
we're inserting the bracket after, rather than potentially at the end of
a comment. When there are open brackets at the end of the file, say that
there are open brackets, not that there's a closing bracket without a
matching opening bracket.
This makes the difference between errors and lower-level diagnostics
visible to users, and aligns the toolchain's behavior with the
expectations in `driver_fuzzer.cpp`.
Rearranges driver logic into CompilationUnits in order to associate
artifacts from the various stages of compilation.
Note, I'm not totally sure what the right thing to do is for
lower/codegen, so I'm just doing a rote change there for now that
mirrors prior phases (this is all the code supports anyways, so is
probably right for now regardless).
SourceBuffer error output is moved local for consistency with other
steps, and so that it's less ambiguous whether the error should be
expected to already include a filename.