mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-09-20 14:41:58 +00:00
83 lines
3 KiB
Rust
83 lines
3 KiB
Rust
const THREE_BITS: i64 = 7;
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const EVEN_MORE_REDIRECTION: i64 = THREE_BITS;
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#[warn(clippy::bad_bit_mask)]
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#[allow(
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clippy::ineffective_bit_mask,
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clippy::identity_op,
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clippy::no_effect,
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clippy::unnecessary_operation
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)]
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fn main() {
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let x = 5;
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x & 0 == 0;
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//~^ ERROR: &-masking with zero
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//~| NOTE: `-D clippy::bad-bit-mask` implied by `-D warnings`
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//~| ERROR: this operation will always return zero. This is likely not the intended ou
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//~| NOTE: `#[deny(clippy::erasing_op)]` on by default
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x & 1 == 1; //ok, distinguishes bit 0
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x & 1 == 0; //ok, compared with zero
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x & 2 == 1;
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//~^ ERROR: incompatible bit mask: `_ & 2` can never be equal to `1`
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x | 0 == 0; //ok, equals x == 0 (maybe warn?)
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x | 1 == 3; //ok, equals x == 2 || x == 3
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x | 3 == 3; //ok, equals x <= 3
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x | 3 == 2;
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//~^ ERROR: incompatible bit mask: `_ | 3` can never be equal to `2`
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x & 1 > 1;
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//~^ ERROR: incompatible bit mask: `_ & 1` will never be higher than `1`
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x & 2 > 1; // ok, distinguishes x & 2 == 2 from x & 2 == 0
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x & 2 < 1; // ok, distinguishes x & 2 == 2 from x & 2 == 0
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x | 1 > 1; // ok (if a bit silly), equals x > 1
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x | 2 > 1;
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//~^ ERROR: incompatible bit mask: `_ | 2` will always be higher than `1`
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x | 2 <= 2; // ok (if a bit silly), equals x <= 2
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x & 192 == 128; // ok, tests for bit 7 and not bit 6
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x & 0xffc0 == 0xfe80; // ok
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// this also now works with constants
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x & THREE_BITS == 8;
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//~^ ERROR: incompatible bit mask: `_ & 7` can never be equal to `8`
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x | EVEN_MORE_REDIRECTION < 7;
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//~^ ERROR: incompatible bit mask: `_ | 7` will never be lower than `7`
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0 & x == 0;
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//~^ ERROR: &-masking with zero
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//~| ERROR: this operation will always return zero. This is likely not the intended ou
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1 | x > 1;
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// and should now also match uncommon usage
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1 < 2 | x;
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//~^ ERROR: incompatible bit mask: `_ | 2` will always be higher than `1`
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2 == 3 | x;
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//~^ ERROR: incompatible bit mask: `_ | 3` can never be equal to `2`
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1 == x & 2;
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//~^ ERROR: incompatible bit mask: `_ & 2` can never be equal to `1`
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x | 1 > 2; // no error, because we allowed ineffective bit masks
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ineffective();
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}
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#[warn(clippy::ineffective_bit_mask)]
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#[allow(clippy::bad_bit_mask, clippy::no_effect, clippy::unnecessary_operation)]
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fn ineffective() {
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let x = 5;
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x | 1 > 3;
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//~^ ERROR: ineffective bit mask: `x | 1` compared to `3`, is the same as x compared d
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//~| NOTE: `-D clippy::ineffective-bit-mask` implied by `-D warnings`
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x | 1 < 4;
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//~^ ERROR: ineffective bit mask: `x | 1` compared to `4`, is the same as x compared d
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x | 1 <= 3;
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//~^ ERROR: ineffective bit mask: `x | 1` compared to `3`, is the same as x compared d
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x | 1 >= 8;
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//~^ ERROR: ineffective bit mask: `x | 1` compared to `8`, is the same as x compared d
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x | 1 > 2; // not an error (yet), better written as x >= 2
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x | 1 >= 7; // not an error (yet), better written as x >= 6
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x | 3 > 4; // not an error (yet), better written as x >= 4
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x | 4 <= 19;
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}
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