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[bad_bit_mask] Fix FP on proc macros (#13736)

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`clap-3.1.6` was not compiling on the rustc-perf benchmarks because of
this lint. Also, the user could not allow the lint on the macro itself
because it was checking Exprs, not whatever the input of `bitflags!` is.

```
error: &-masking with zero
   --> src/build/arg_settings.rs:197:1
    |
            (#[allow] here)
197 | / bitflags! {
198 | |     struct Flags: u32 {
199 | |         const REQUIRED         ...
200 | |         const MULTIPLE_OCC     ...
...   |
226 | |     }
227 | | }
    | |_^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#bad_bit_mask
    = note: this error originates in the macro `__impl_bitflags` which comes from the expansion of the macro `bitflags` (in Nightly builds, run with -Z macro-backtrace for more info)
```

changelog:  [`bad_bit_mask`]: Fix FP on procedural macros
This commit is contained in:
Jason Newcomb 2024-11-27 20:31:29 +00:00 • committed by GitHub
commit b4163f08c7
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1 changed files with 3 additions and 2 deletions
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5
clippy_lints/src/operators/bit_mask.rs
View file

@ -1,5 +1,6 @@
use clippy_utils::consts::{ConstEvalCtxt, Constant};
use clippy_utils::diagnostics::span_lint;
use clippy_utils::is_from_proc_macro;
use rustc_hir::{BinOpKind, Expr, ExprKind};
use rustc_lint::LateContext;
use rustc_span::Span;
@ -35,9 +36,9 @@ fn invert_cmp(cmp: BinOpKind) -> BinOpKind {
}
}
fn check_compare(cx: &LateContext<'_>, bit_op: &Expr<'_>, cmp_op: BinOpKind, cmp_value: u128, span: Span) {
fn check_compare<'a>(cx: &LateContext<'a>, bit_op: &Expr<'a>, cmp_op: BinOpKind, cmp_value: u128, span: Span) {
if let ExprKind::Binary(op, left, right) = &bit_op.kind {
if op.node != BinOpKind::BitAnd && op.node != BinOpKind::BitOr {
if op.node != BinOpKind::BitAnd && op.node != BinOpKind::BitOr || is_from_proc_macro(cx, bit_op) {
return;
}
if let Some(mask) = fetch_int_literal(cx, right).or_else(|| fetch_int_literal(cx, left)) {