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.
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 removes a (very) hot branch in the lexer where we need to special
case when a token is the first token and can't look at its previous
token. It also seems like a generally nice change to the structure of
both the token buffer and parse tree as there are now bracketing
elements for both ends and we should be able to avoid similar branching
in the future.
Mostly mechanical updates to the lexer and parser code to handle this,
but also needed to special case the location information in the
autoupdate code. And then the usual large body of auto-updated tests.
No benchmark data for this change alone as in isolation and in the
current lexer structure it doesn't make a big difference. But this
branch was particularly difficult to handle when trying to update the
whitespace skipping code to be faster, and so I think it is worth
systematically avoiding the special case here.
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`.
Continuing with #3070. Just a dir and file rename (mostly removing
prefixes, although for parse_tree_fuzzer and parse_tree_file_test I'm
dropping "tree" instead of "parse"). Everything in the parse dir should
be marked as a move.
Jon Ross-Perkins
Richard Smith
josh11bandJon Ross-Perkins
Geoff Romer
Chandler Carruth