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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 /src/test/ui/numbers-arithmetic/overflowing-lsh-4.rs | |
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 'src/test/ui/numbers-arithmetic/overflowing-lsh-4.rs')
-rw-r--r-- | src/test/ui/numbers-arithmetic/overflowing-lsh-4.rs | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/numbers-arithmetic/overflowing-lsh-4.rs b/src/test/ui/numbers-arithmetic/overflowing-lsh-4.rs new file mode 100644 index 000000000..738d01339 --- /dev/null +++ b/src/test/ui/numbers-arithmetic/overflowing-lsh-4.rs @@ -0,0 +1,24 @@ +// build-fail +// compile-flags: -C debug-assertions + +// This function is checking that our automatic truncation does not +// sidestep the overflow checking. + +#![deny(arithmetic_overflow, const_err)] + +fn main() { + // this signals overflow when checking is on + let x = 1_i8 << 17; + //~^ ERROR: this arithmetic operation will overflow + + // ... but when checking is off, the fallback will truncate the + // input to its lower three bits (= 1). Note that this is *not* + // the behavior of the x86 processor for 8- and 16-bit types, + // but it is necessary to avoid undefined behavior from LLVM. + // + // We check that here, by ensuring the result has only been + // shifted by one place; if overflow checking is turned off, then + // this assertion will pass (and the compiletest driver will + // report that the test did not produce the error expected above). + assert_eq!(x, 2_i8); +} |