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Merge pull request #90 from Manishearth/bit_mask

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fixed issue #88 in bit_mask
This commit is contained in:
llogiq 2015-06-06 02:32:37 +02:00
parent cfcf5ac8e5 8563ee60ec
commit 5874466646
2 changed files with 17 additions and 8 deletions
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24
src/bit_mask.rs
View file

@ -89,20 +89,26 @@ fn check_compare(cx: &Context, bit_op: &Expr, cmp_op: BinOp_, cmp_value: u64, sp
}
}
fn check_bit_mask(cx: &Context, bit_op: BinOp_, cmp_op: BinOp_, mask_value: u64, cmp_value: u64, span: &Span) {
fn check_bit_mask(cx: &Context, bit_op: BinOp_, cmp_op: BinOp_,
mask_value: u64, cmp_value: u64, span: &Span) {
match cmp_op {
BiEq | BiNe => match bit_op {
BiBitAnd => if mask_value & cmp_value != mask_value {
cx.span_lint(BAD_BIT_MASK, *span, &format!("incompatible bit mask: _ & {} can never be equal to {}", mask_value,
cmp_value));
if cmp_value != 0 {
cx.span_lint(BAD_BIT_MASK, *span, &format!(
"incompatible bit mask: _ & {} can never be equal to {}",
mask_value, cmp_value));
}
} else {
if mask_value == 0 {
cx.span_lint(BAD_BIT_MASK, *span, &format!("&-masking with zero"));
cx.span_lint(BAD_BIT_MASK, *span,
&format!("&-masking with zero"));
}
},
BiBitOr => if mask_value | cmp_value != cmp_value {
cx.span_lint(BAD_BIT_MASK, *span, &format!("incompatible bit mask: _ | {} can never be equal to {}", mask_value,
cmp_value));
cx.span_lint(BAD_BIT_MASK, *span, &format!(
"incompatible bit mask: _ | {} can never be equal to {}",
mask_value, cmp_value));
},
_ => ()
},
@ -113,7 +119,8 @@ fn check_bit_mask(cx: &Context, bit_op: BinOp_, cmp_op: BinOp_, mask_value: u64,
mask_value, cmp_value));
} else {
if mask_value == 0 {
cx.span_lint(BAD_BIT_MASK, *span, &format!("&-masking with zero"));
cx.span_lint(BAD_BIT_MASK, *span,
&format!("&-masking with zero"));
}
},
BiBitOr => if mask_value >= cmp_value {
@ -136,7 +143,8 @@ fn check_bit_mask(cx: &Context, bit_op: BinOp_, cmp_op: BinOp_, mask_value: u64,
mask_value, cmp_value));
} else {
if mask_value == 0 {
cx.span_lint(BAD_BIT_MASK, *span, &format!("&-masking with zero"));
cx.span_lint(BAD_BIT_MASK, *span,
&format!("&-masking with zero"));
}
},
BiBitOr => if mask_value > cmp_value {

1
tests/compile-fail/bit_masks.rs
View file

@ -11,6 +11,7 @@ fn main() {
x & 0 == 0; //~ERROR &-masking with zero
x & 1 == 1; //ok, distinguishes bit 0
x & 1 == 0; //ok, compared with zero
x & 2 == 1; //~ERROR
x | 0 == 0; //ok, equals x == 0 (maybe warn?)
x | 1 == 3; //ok, equals x == 2 || x == 3