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expand: Do not report cfg_attr traces on macros as unused attributes #138794

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Merged
merged 1 commit into from
Mar 22, 2025
Merged

expand: Do not report cfg_attr traces on macros as unused attributes #138794

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2 changes: 1 addition & 1 deletion compiler/rustc_expand/src/expand.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1941,7 +1941,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
let attr_name = attr.ident().unwrap().name;
// `#[cfg]` and `#[cfg_attr]` are special - they are
// eagerly evaluated.
if attr_name != sym::cfg && attr_name != sym::cfg_attr {
if attr_name != sym::cfg && attr_name != sym::cfg_attr_trace {
self.cx.sess.psess.buffer_lint(
UNUSED_ATTRIBUTES,
attr.span,
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7 changes: 7 additions & 0 deletions tests/ui/lint/inert-attr-macro.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
//@ check-pass

#![feature(cfg_boolean_literals)]
#![warn(unused)]

macro_rules! foo {
Expand All @@ -17,4 +18,10 @@ fn main() {
// This does work, since the attribute is on a parent
// of the macro invocation.
#[allow(warnings)] { #[inline] foo!(); }

// Ok, `cfg` and `cfg_attr` are expanded eagerly and do not warn.
#[cfg(true)] foo!();
#[cfg(false)] foo!();
#[cfg_attr(true, cfg(true))] foo!();
#[cfg_attr(false, nonexistent)] foo!();
}
14 changes: 7 additions & 7 deletions tests/ui/lint/inert-attr-macro.stderr
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Original file line number Diff line number Diff line change
@@ -1,41 +1,41 @@
warning: unused attribute `inline`
--> $DIR/inert-attr-macro.rs:10:5
--> $DIR/inert-attr-macro.rs:11:5
|
LL | #[inline] foo!();
| ^^^^^^^^^
|
note: the built-in attribute `inline` will be ignored, since it's applied to the macro invocation `foo`
--> $DIR/inert-attr-macro.rs:10:15
--> $DIR/inert-attr-macro.rs:11:15
|
LL | #[inline] foo!();
| ^^^
note: the lint level is defined here
--> $DIR/inert-attr-macro.rs:3:9
--> $DIR/inert-attr-macro.rs:4:9
|
LL | #![warn(unused)]
| ^^^^^^
= note: `#[warn(unused_attributes)]` implied by `#[warn(unused)]`

warning: unused attribute `allow`
--> $DIR/inert-attr-macro.rs:14:5
--> $DIR/inert-attr-macro.rs:15:5
|
LL | #[allow(warnings)] #[inline] foo!();
| ^^^^^^^^^^^^^^^^^^
|
note: the built-in attribute `allow` will be ignored, since it's applied to the macro invocation `foo`
--> $DIR/inert-attr-macro.rs:14:34
--> $DIR/inert-attr-macro.rs:15:34
|
LL | #[allow(warnings)] #[inline] foo!();
| ^^^

warning: unused attribute `inline`
--> $DIR/inert-attr-macro.rs:14:24
--> $DIR/inert-attr-macro.rs:15:24
|
LL | #[allow(warnings)] #[inline] foo!();
| ^^^^^^^^^
|
note: the built-in attribute `inline` will be ignored, since it's applied to the macro invocation `foo`
--> $DIR/inert-attr-macro.rs:14:34
--> $DIR/inert-attr-macro.rs:15:34
|
LL | #[allow(warnings)] #[inline] foo!();
| ^^^
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