| commit | 09ada1af8f54584e46deb0d643713393a9d83b10 | [log] [tgz] |
|---|---|---|
| author | Robert Griesemer <gri@golang.org> | Mon Apr 25 16:26:10 2022 -0700 |
| committer | Gopher Robot <gobot@golang.org> | Tue Apr 26 02:19:42 2022 +0000 |
| tree | 8589fdc5ac30ebdbe3ad4d1432462ee3925a1024 | |
| parent | e845750744b648b8b348bbcebe2ff85d4e6247c5 [diff] |
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>
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