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author | Robert Griesemer <gri@golang.org> | 2022-04-25 16:26:10 -0700 |
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committer | Gopher Robot <gobot@golang.org> | 2022-04-26 02:19:42 +0000 |
commit | 09ada1af8f54584e46deb0d643713393a9d83b10 (patch) | |
tree | 8589fdc5ac30ebdbe3ad4d1432462ee3925a1024 /src/time/time_test.go | |
parent | e845750744b648b8b348bbcebe2ff85d4e6247c5 (diff) | |
download | go-09ada1af8f54584e46deb0d643713393a9d83b10.tar.gz go-09ada1af8f54584e46deb0d643713393a9d83b10.zip |
cmd/compile/internal/syntax: parser to accept ~x as unary expression
Accept ~x as ordinary unary expression in the parser but recognize
such expressions as invalid in the type checker.
This change opens the door to recognizing complex type constraint
literals such as `*E|~int` in `[P *E|~int]` and parse them correctly
instead of reporting a parse error because `P*E|~int` syntactically
looks like an incorrect array length expression (binary expression
where the RHS of | is an invalid unary expression ~int).
As a result, the parser is more forgiving with expressions but the
type checker will reject invalid uses as before.
We could pass extra information into the binary/unary expression
parse functions to prevent the use of ~ in invalid situations but
it doesn't seem worth the trouble. In fact it may be advantageous
to allow a more liberal expression syntax especially in the presence
of errors (better parser synchronization after an error).
Preparation for fixing #49482.
Change-Id: I119e8bd9445dfa6460fcd7e0658e3554a34b2769
Reviewed-on: https://go-review.googlesource.com/c/go/+/402255
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Diffstat (limited to 'src/time/time_test.go')
0 files changed, 0 insertions, 0 deletions