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Unrolled build for rust-lang#123314
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Rollup merge of rust-lang#123314 - surechen:fix_120642, r=Nadrieril

Skip `unused_parens` report for `Paren(Path(..))` in macro.

fixes rust-lang#120642

In following code, `unused_parens` suggest change `<($($rest),*)>::bar()` to `<$rest>::bar()`  which will cause another err: `error: variable 'rest' is still repeating at this depth`:

```rust
trait Foo {
    fn bar();
}

macro_rules! problem {
    ($ty:ident) => {
        impl<$ty: Foo> Foo for ($ty,) {
            fn bar() { <$ty>::bar() }
        }
    };
    ($ty:ident $(, $rest:ident)*) => {
        impl<$ty: Foo, $($rest: Foo),*> Foo for ($ty, $($rest),*) {
            fn bar() {
                <$ty>::bar();
                <($($rest),*)>::bar()
            }
        }
        problem!($($rest),*);
    }
}
```

I think maybe we can handle this by avoid warning for `Paren(Path(..))` in the macro. Is this reasonable approach?
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rust-timer authored Apr 11, 2024
2 parents aa067fb + c8490a0 commit 1ecac1c
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Showing 3 changed files with 94 additions and 9 deletions.
24 changes: 15 additions & 9 deletions compiler/rustc_lint/src/unused.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1074,10 +1074,14 @@ impl UnusedParens {
// Otherwise proceed with linting.
_ => {}
}
let spans = inner
.span
.find_ancestor_inside(value.span)
.map(|inner| (value.span.with_hi(inner.lo()), value.span.with_lo(inner.hi())));
let spans = if !value.span.from_expansion() {
inner
.span
.find_ancestor_inside(value.span)
.map(|inner| (value.span.with_hi(inner.lo()), value.span.with_lo(inner.hi())))
} else {
None
};
self.emit_unused_delims(cx, value.span, spans, "pattern", keep_space, false);
}
}
Expand Down Expand Up @@ -1233,11 +1237,13 @@ impl EarlyLintPass for UnusedParens {
if self.with_self_ty_parens && b.generic_params.len() > 0 => {}
ast::TyKind::ImplTrait(_, bounds) if bounds.len() > 1 => {}
_ => {
let spans = r
.span
.find_ancestor_inside(ty.span)
.map(|r| (ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())));

let spans = if !ty.span.from_expansion() {
r.span
.find_ancestor_inside(ty.span)
.map(|r| (ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())))
} else {
None
};
self.emit_unused_delims(cx, ty.span, spans, "type", (false, false), false);
}
}
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,39 @@
//@ run-pass

#![warn(unused_parens)]
#![allow(dead_code)]

trait Foo {
fn bar();
fn tar();
}

macro_rules! unused_parens {
($ty:ident) => {
impl<$ty: Foo> Foo for ($ty,) {
fn bar() { <$ty>::bar() }
fn tar() {}
}
};

($ty:ident $(, $rest:ident)*) => {
impl<$ty: Foo, $($rest: Foo),*> Foo for ($ty, $($rest),*) {
fn bar() {
<$ty>::bar();
<($($rest),*)>::bar() //~WARN unnecessary parentheses around type
}
fn tar() {
let (_t) = 1; //~WARN unnecessary parentheses around pattern
//~| WARN unnecessary parentheses around pattern
let (_t1,) = (1,);
let (_t2, _t3) = (1, 2);
}
}

unused_parens!($($rest),*);
}
}

unused_parens!(T1, T2, T3);

fn main() {}
Original file line number Diff line number Diff line change
@@ -0,0 +1,40 @@
warning: unnecessary parentheses around pattern
--> $DIR/unused-parens-in-macro-issue-120642.rs:26:19
|
LL | let (_t) = 1;
| ^^^^
...
LL | unused_parens!(T1, T2, T3);
| -------------------------- in this macro invocation
|
note: the lint level is defined here
--> $DIR/unused-parens-in-macro-issue-120642.rs:3:9
|
LL | #![warn(unused_parens)]
| ^^^^^^^^^^^^^
= note: this warning originates in the macro `unused_parens` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: unnecessary parentheses around type
--> $DIR/unused-parens-in-macro-issue-120642.rs:23:18
|
LL | <($($rest),*)>::bar()
| ^^^^^^^^^^^^
...
LL | unused_parens!(T1, T2, T3);
| -------------------------- in this macro invocation
|
= note: this warning originates in the macro `unused_parens` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: unnecessary parentheses around pattern
--> $DIR/unused-parens-in-macro-issue-120642.rs:26:19
|
LL | let (_t) = 1;
| ^^^^
...
LL | unused_parens!(T1, T2, T3);
| -------------------------- in this macro invocation
|
= note: this warning originates in the macro `unused_parens` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: 3 warnings emitted

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