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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:03:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:03:36 +0000 |
commit | 17d40c6057c88f4c432b0d7bac88e1b84cb7e67f (patch) | |
tree | 3f66c4a5918660bb8a758ab6cda5ff8ee4f6cdcd /src/tools/clippy/src/docs/ineffective_bit_mask.txt | |
parent | Adding upstream version 1.64.0+dfsg1. (diff) | |
download | rustc-f7f0cc2a5d72e2c61c1f6900e70eec992bea4273.tar.xz rustc-f7f0cc2a5d72e2c61c1f6900e70eec992bea4273.zip |
Adding upstream version 1.65.0+dfsg1.upstream/1.65.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tools/clippy/src/docs/ineffective_bit_mask.txt')
-rw-r--r-- | src/tools/clippy/src/docs/ineffective_bit_mask.txt | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/src/tools/clippy/src/docs/ineffective_bit_mask.txt b/src/tools/clippy/src/docs/ineffective_bit_mask.txt new file mode 100644 index 000000000..f6e7ef556 --- /dev/null +++ b/src/tools/clippy/src/docs/ineffective_bit_mask.txt @@ -0,0 +1,25 @@ +### What it does +Checks for bit masks in comparisons which can be removed +without changing the outcome. The basic structure can be seen in the +following table: + +|Comparison| Bit Op |Example |equals | +|----------|----------|------------|-------| +|`>` / `<=`|`\|` / `^`|`x \| 2 > 3`|`x > 3`| +|`<` / `>=`|`\|` / `^`|`x ^ 1 < 4` |`x < 4`| + +### Why is this bad? +Not equally evil as [`bad_bit_mask`](#bad_bit_mask), +but still a bit misleading, because the bit mask is ineffective. + +### Known problems +False negatives: This lint will only match instances +where we have figured out the math (which is for a power-of-two compared +value). This means things like `x | 1 >= 7` (which would be better written +as `x >= 6`) will not be reported (but bit masks like this are fairly +uncommon). + +### Example +``` +if (x | 1 > 3) { } +```
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