diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs index 255ff56f62b1d..93df056c43b92 100644 --- a/compiler/rustc_lint/src/builtin.rs +++ b/compiler/rustc_lint/src/builtin.rs @@ -1584,6 +1584,8 @@ impl EarlyLintPass for DoubleNegations { if let ExprKind::Unary(UnOp::Neg, ref inner) = expr.kind && let ExprKind::Unary(UnOp::Neg, ref inner2) = inner.kind && !matches!(inner2.kind, ExprKind::Unary(UnOp::Neg, _)) + // Don't lint if this jumps macro expansion boundary (Issue #143980) + && expr.span.eq_ctxt(inner.span) { cx.emit_span_lint( DOUBLE_NEGATIONS, diff --git a/tests/ui/lint/lint-double-negations-macro.rs b/tests/ui/lint/lint-double-negations-macro.rs new file mode 100644 index 0000000000000..a6583271d5a2a --- /dev/null +++ b/tests/ui/lint/lint-double-negations-macro.rs @@ -0,0 +1,16 @@ +//@ check-pass +macro_rules! neg { + ($e: expr) => { + -$e + }; +} +macro_rules! bad_macro { + ($e: expr) => { + --$e //~ WARN use of a double negation + }; +} + +fn main() { + neg!(-1); + bad_macro!(1); +} diff --git a/tests/ui/lint/lint-double-negations-macro.stderr b/tests/ui/lint/lint-double-negations-macro.stderr new file mode 100644 index 0000000000000..d6ac9be48f304 --- /dev/null +++ b/tests/ui/lint/lint-double-negations-macro.stderr @@ -0,0 +1,20 @@ +warning: use of a double negation + --> $DIR/lint-double-negations-macro.rs:9:9 + | +LL | --$e + | ^^^^ +... +LL | bad_macro!(1); + | ------------- in this macro invocation + | + = note: the prefix `--` could be misinterpreted as a decrement operator which exists in other languages + = note: use `-= 1` if you meant to decrement the value + = note: `#[warn(double_negations)]` on by default + = note: this warning originates in the macro `bad_macro` (in Nightly builds, run with -Z macro-backtrace for more info) +help: add parentheses for clarity + | +LL | -(-$e) + | + + + +warning: 1 warning emitted +