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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_error_codes/src/error_codes/E0301.md | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_error_codes/src/error_codes/E0301.md')
-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0301.md | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0301.md b/compiler/rustc_error_codes/src/error_codes/E0301.md new file mode 100644 index 000000000..485e19fbb --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0301.md @@ -0,0 +1,17 @@ +#### Note: this error code is no longer emitted by the compiler. + +Mutable borrows are not allowed in pattern guards, because matching cannot have +side effects. Side effects could alter the matched object or the environment +on which the match depends in such a way, that the match would not be +exhaustive. For instance, the following would not match any arm if mutable +borrows were allowed: + +```compile_fail,E0596 +match Some(()) { + None => { }, + option if option.take().is_none() => { + /* impossible, option is `Some` */ + }, + Some(_) => { } // When the previous match failed, the option became `None`. +} +``` |