Revert recent changes to dead code analysis

library/core/src/default.rs

@@ -103,6 +103,7 @@ use crate::ascii::Char as AsciiChar;
 /// ```
 #[cfg_attr(not(test), rustc_diagnostic_item = "Default")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(bootstrap), rustc_trivial_field_reads)]
 pub trait Default: Sized {
     /// Returns the "default value" for a type.
     ///

library/std/src/sys/pal/unix/pipe.rs

@@ -47,6 +47,8 @@ pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
 }
 
 impl AnonPipe {
+    #[allow(dead_code)]
+    // FIXME: This function seems legitimately unused.
     pub fn try_clone(&self) -> io::Result<Self> {
         self.0.duplicate().map(Self)
     }
@@ -85,6 +87,8 @@ impl AnonPipe {
         self.0.is_write_vectored()
     }
 
+    #[allow(dead_code)]
+    // FIXME: This function seems legitimately unused.
     pub fn as_file_desc(&self) -> &FileDesc {
         &self.0
     }

src/bootstrap/src/core/build_steps/check.rs

@@ -31,10 +31,6 @@ pub struct Std {
 }
 
 impl Std {
-    pub fn new(target: TargetSelection) -> Self {
-        Self::new_with_build_kind(target, None)
-    }
-
     pub fn new_with_build_kind(target: TargetSelection, kind: Option<Kind>) -> Self {
         Self { target, crates: vec![], override_build_kind: kind }
     }

tests/codegen-units/item-collection/generic-impl.rs

@@ -22,16 +22,16 @@ impl<T> Struct<T> {
     }
 }
 
-pub struct _LifeTimeOnly<'a> {
+pub struct LifeTimeOnly<'a> {
     _a: &'a u32,
 }
 
-impl<'a> _LifeTimeOnly<'a> {
-    //~ MONO_ITEM fn _LifeTimeOnly::<'_>::foo
+impl<'a> LifeTimeOnly<'a> {
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::foo
     pub fn foo(&self) {}
-    //~ MONO_ITEM fn _LifeTimeOnly::<'_>::bar
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::bar
     pub fn bar(&'a self) {}
-    //~ MONO_ITEM fn _LifeTimeOnly::<'_>::baz
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::baz
     pub fn baz<'b>(&'b self) {}
 
     pub fn non_instantiated<T>(&self) {}

tests/codegen-units/item-collection/overloaded-operators.rs

@@ -5,44 +5,44 @@
 
 use std::ops::{Add, Deref, Index, IndexMut};
 
-pub struct _Indexable {
+pub struct Indexable {
     data: [u8; 3],
 }
 
-impl Index<usize> for _Indexable {
+impl Index<usize> for Indexable {
     type Output = u8;
 
-    //~ MONO_ITEM fn <_Indexable as std::ops::Index<usize>>::index
+    //~ MONO_ITEM fn <Indexable as std::ops::Index<usize>>::index
     fn index(&self, index: usize) -> &Self::Output {
         if index >= 3 { &self.data[0] } else { &self.data[index] }
     }
 }
 
-impl IndexMut<usize> for _Indexable {
-    //~ MONO_ITEM fn <_Indexable as std::ops::IndexMut<usize>>::index_mut
+impl IndexMut<usize> for Indexable {
+    //~ MONO_ITEM fn <Indexable as std::ops::IndexMut<usize>>::index_mut
     fn index_mut(&mut self, index: usize) -> &mut Self::Output {
         if index >= 3 { &mut self.data[0] } else { &mut self.data[index] }
     }
 }
 
-//~ MONO_ITEM fn <_Equatable as std::cmp::PartialEq>::eq
-//~ MONO_ITEM fn <_Equatable as std::cmp::PartialEq>::ne
+//~ MONO_ITEM fn <Equatable as std::cmp::PartialEq>::eq
+//~ MONO_ITEM fn <Equatable as std::cmp::PartialEq>::ne
 #[derive(PartialEq)]
-pub struct _Equatable(u32);
+pub struct Equatable(u32);
 
-impl Add<u32> for _Equatable {
+impl Add<u32> for Equatable {
     type Output = u32;
 
-    //~ MONO_ITEM fn <_Equatable as std::ops::Add<u32>>::add
+    //~ MONO_ITEM fn <Equatable as std::ops::Add<u32>>::add
     fn add(self, rhs: u32) -> u32 {
         self.0 + rhs
     }
 }
 
-impl Deref for _Equatable {
+impl Deref for Equatable {
     type Target = u32;
 
-    //~ MONO_ITEM fn <_Equatable as std::ops::Deref>::deref
+    //~ MONO_ITEM fn <Equatable as std::ops::Deref>::deref
     fn deref(&self) -> &Self::Target {
         &self.0
     }

tests/ui/coherence/re-rebalance-coherence.rs

@@ -4,7 +4,6 @@
 extern crate re_rebalance_coherence_lib as lib;
 use lib::*;
 
-#[allow(dead_code)]
 struct Oracle;
 impl Backend for Oracle {}
 impl<'a, T:'a, Tab> QueryFragment<Oracle> for BatchInsert<'a, T, Tab> {}

tests/ui/const-generics/cross_crate_complex.rs

@@ -11,7 +11,6 @@ async fn foo() {
     async_in_foo(async_out_foo::<4>().await).await;
 }
 
-#[allow(dead_code)]
 struct Faz<const N: usize>;
 
 impl<const N: usize> Foo<N> for Faz<N> {}

tests/ui/const-generics/defaults/repr-c-issue-82792.rs

@@ -2,7 +2,6 @@
 
 //@ run-pass
 
-#[allow(dead_code)]
 #[repr(C)]
 pub struct Loaf<T: Sized, const N: usize = 1> {
     head: [T; N],

tests/ui/const-generics/generic_const_exprs/associated-consts.rs

@@ -16,8 +16,7 @@ impl BlockCipher for BarCipher {
     const BLOCK_SIZE: usize = 32;
 }
 
-#[allow(dead_code)]
-pub struct Block<C>(C);
+pub struct Block<C>(#[allow(dead_code)] C);
 
 pub fn test<C: BlockCipher, const M: usize>()
 where

tests/ui/const-generics/issues/issue-86535-2.rs

@@ -9,7 +9,6 @@ pub trait Foo {
         [(); Self::ASSOC_C]:;
 }
 
-#[allow(dead_code)]
 struct Bar<const N: &'static ()>;
 impl<const N: &'static ()> Foo for Bar<N> {
     const ASSOC_C: usize = 3;

tests/ui/const-generics/issues/issue-86535.rs

@@ -2,7 +2,6 @@
 #![feature(adt_const_params, unsized_const_params, generic_const_exprs)]
 #![allow(incomplete_features, unused_variables)]
 
-#[allow(dead_code)]
 struct F<const S: &'static str>;
 impl<const S: &'static str> X for F<{ S }> {
     const W: usize = 3;

tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs

@@ -6,7 +6,6 @@
 
 use std::mem::MaybeUninit;
 
-#[allow(dead_code)]
 #[repr(transparent)]
 pub struct MaybeUninitWrapper<const N: usize>(MaybeUninit<[u64; N]>);
 

tests/ui/generic-associated-types/missing-bounds.fixed

@@ -2,7 +2,6 @@
 
 use std::ops::Add;
 
-#[allow(dead_code)]
 struct A<B>(B);
 
 impl<B> Add for A<B> where B: Add<Output = B> {
@@ -13,7 +12,6 @@ impl<B> Add for A<B> where B: Add<Output = B> {
     }
 }
 
-#[allow(dead_code)]
 struct C<B>(B);
 
 impl<B: Add<Output = B>> Add for C<B> {
@@ -24,7 +22,6 @@ impl<B: Add<Output = B>> Add for C<B> {
     }
 }
 
-#[allow(dead_code)]
 struct D<B>(B);
 
 impl<B: std::ops::Add<Output = B>> Add for D<B> {
@@ -35,7 +32,6 @@ impl<B: std::ops::Add<Output = B>> Add for D<B> {
     }
 }
 
-#[allow(dead_code)]
 struct E<B>(B);
 
 impl<B: Add<Output = B>> Add for E<B> where B: Add<Output = B> {

tests/ui/generic-associated-types/missing-bounds.rs

@@ -2,7 +2,6 @@
 
 use std::ops::Add;
 
-#[allow(dead_code)]
 struct A<B>(B);
 
 impl<B> Add for A<B> where B: Add {
@@ -13,7 +12,6 @@ impl<B> Add for A<B> where B: Add {
     }
 }
 
-#[allow(dead_code)]
 struct C<B>(B);
 
 impl<B: Add> Add for C<B> {
@@ -24,7 +22,6 @@ impl<B: Add> Add for C<B> {
     }
 }
 
-#[allow(dead_code)]
 struct D<B>(B);
 
 impl<B> Add for D<B> {
@@ -35,7 +32,6 @@ impl<B> Add for D<B> {
     }
 }
 
-#[allow(dead_code)]
 struct E<B>(B);
 
 impl<B: Add> Add for E<B> where <B as Add>::Output = B {

tests/ui/generic-associated-types/missing-bounds.stderr

@@ -1,5 +1,5 @@
 error: equality constraints are not yet supported in `where` clauses
-  --> $DIR/missing-bounds.rs:41:33
+  --> $DIR/missing-bounds.rs:37:33
    |
 LL | impl<B: Add> Add for E<B> where <B as Add>::Output = B {
    |                                 ^^^^^^^^^^^^^^^^^^^^^^ not supported
@@ -11,7 +11,7 @@ LL | impl<B: Add> Add for E<B> where B: Add<Output = B> {
    |                                 ~~~~~~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:12:11
+  --> $DIR/missing-bounds.rs:11:11
    |
 LL | impl<B> Add for A<B> where B: Add {
    |      - expected this type parameter
@@ -24,14 +24,14 @@ LL |         A(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 help: the type constructed contains `<B as Add>::Output` due to the type of the argument passed
-  --> $DIR/missing-bounds.rs:12:9
+  --> $DIR/missing-bounds.rs:11:9
    |
 LL |         A(self.0 + rhs.0)
    |         ^^--------------^
    |           |
    |           this argument influences the type of `A`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:6:8
+  --> $DIR/missing-bounds.rs:5:8
    |
 LL | struct A<B>(B);
    |        ^
@@ -41,7 +41,7 @@ LL | impl<B> Add for A<B> where B: Add<Output = B> {
    |                                  ++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:23:14
+  --> $DIR/missing-bounds.rs:21:14
    |
 LL | impl<B: Add> Add for C<B> {
    |      - expected this type parameter
@@ -54,7 +54,7 @@ LL |         Self(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:17:8
+  --> $DIR/missing-bounds.rs:15:8
    |
 LL | struct C<B>(B);
    |        ^
@@ -64,7 +64,7 @@ LL | impl<B: Add<Output = B>> Add for C<B> {
    |            ++++++++++++
 
 error[E0369]: cannot add `B` to `B`
-  --> $DIR/missing-bounds.rs:34:21
+  --> $DIR/missing-bounds.rs:31:21
    |
 LL |         Self(self.0 + rhs.0)
    |              ------ ^ ----- B
@@ -77,7 +77,7 @@ LL | impl<B: std::ops::Add<Output = B>> Add for D<B> {
    |       +++++++++++++++++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:46:14
+  --> $DIR/missing-bounds.rs:42:14
    |
 LL | impl<B: Add> Add for E<B> where <B as Add>::Output = B {
    |      - expected this type parameter
@@ -90,7 +90,7 @@ LL |         Self(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:39:8
+  --> $DIR/missing-bounds.rs:35:8
    |
 LL | struct E<B>(B);
    |        ^

tests/ui/impl-trait/extra-impl-in-trait-impl.fixed

@@ -1,8 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct S<T>(T);
-#[allow(dead_code)]
 struct S2;
 
 impl<T: Default> Default for S<T> {

tests/ui/impl-trait/extra-impl-in-trait-impl.rs

@@ -1,8 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct S<T>(T);
-#[allow(dead_code)]
 struct S2;
 
 impl<T: Default> impl Default for S<T> {

tests/ui/impl-trait/extra-impl-in-trait-impl.stderr

@@ -1,23 +1,23 @@
 error: unexpected `impl` keyword
-  --> $DIR/extra-impl-in-trait-impl.rs:8:18
+  --> $DIR/extra-impl-in-trait-impl.rs:6:18
    |
 LL | impl<T: Default> impl Default for S<T> {
    |                  ^^^^^ help: remove the extra `impl`
    |
 note: this is parsed as an `impl Trait` type, but a trait is expected at this position
-  --> $DIR/extra-impl-in-trait-impl.rs:8:18
+  --> $DIR/extra-impl-in-trait-impl.rs:6:18
    |
 LL | impl<T: Default> impl Default for S<T> {
    |                  ^^^^^^^^^^^^
 
 error: unexpected `impl` keyword
-  --> $DIR/extra-impl-in-trait-impl.rs:14:6
+  --> $DIR/extra-impl-in-trait-impl.rs:12:6
    |
 LL | impl impl Default for S2 {
    |      ^^^^^ help: remove the extra `impl`
    |
 note: this is parsed as an `impl Trait` type, but a trait is expected at this position
-  --> $DIR/extra-impl-in-trait-impl.rs:14:6
+  --> $DIR/extra-impl-in-trait-impl.rs:12:6
    |
 LL | impl impl Default for S2 {
    |      ^^^^^^^^^^^^

tests/ui/issues/issue-5708.rs

@@ -44,7 +44,6 @@ pub trait MyTrait<T> {
     fn dummy(&self, t: T) -> T { panic!() }
 }
 
-#[allow(dead_code)]
 pub struct MyContainer<'a, T:'a> {
     foos: Vec<&'a (dyn MyTrait<T>+'a)> ,
 }

tests/ui/lint/dead-code/issue-59003.rs

@@ -4,8 +4,8 @@
 
 #![deny(dead_code)]
 
-#[allow(dead_code)]
 struct Foo {
+    #[allow(dead_code)]
     inner: u32,
 }
 

tests/ui/lint/dead-code/lint-dead-code-1.rs

@@ -46,10 +46,11 @@ struct SemiUsedStruct;
 impl SemiUsedStruct {
     fn la_la_la() {}
 }
-struct StructUsedAsField; //~ ERROR struct `StructUsedAsField` is never constructed
+struct StructUsedAsField;
 pub struct StructUsedInEnum;
 struct StructUsedInGeneric;
-pub struct PubStruct2 { //~ ERROR struct `PubStruct2` is never constructed
+pub struct PubStruct2 {
+    #[allow(dead_code)]
     struct_used_as_field: *const StructUsedAsField
 }
 

tests/ui/lint/dead-code/lint-dead-code-1.stderr

@@ -22,26 +22,14 @@ error: struct `PrivStruct` is never constructed
 LL | struct PrivStruct;
    |        ^^^^^^^^^^
 
-error: struct `StructUsedAsField` is never constructed
-  --> $DIR/lint-dead-code-1.rs:49:8
-   |
-LL | struct StructUsedAsField;
-   |        ^^^^^^^^^^^^^^^^^
-
-error: struct `PubStruct2` is never constructed
-  --> $DIR/lint-dead-code-1.rs:52:12
-   |
-LL | pub struct PubStruct2 {
-   |            ^^^^^^^^^^
-
 error: enum `priv_enum` is never used
-  --> $DIR/lint-dead-code-1.rs:63:6
+  --> $DIR/lint-dead-code-1.rs:64:6
    |
 LL | enum priv_enum { foo2, bar2 }
    |      ^^^^^^^^^
 
 error: variant `bar3` is never constructed
-  --> $DIR/lint-dead-code-1.rs:66:5
+  --> $DIR/lint-dead-code-1.rs:67:5
    |
 LL | enum used_enum {
    |      --------- variant in this enum
@@ -50,25 +38,25 @@ LL |     bar3
    |     ^^^^
 
 error: function `priv_fn` is never used
-  --> $DIR/lint-dead-code-1.rs:87:4
+  --> $DIR/lint-dead-code-1.rs:88:4
    |
 LL | fn priv_fn() {
    |    ^^^^^^^
 
 error: function `foo` is never used
-  --> $DIR/lint-dead-code-1.rs:92:4
+  --> $DIR/lint-dead-code-1.rs:93:4
    |
 LL | fn foo() {
    |    ^^^
 
 error: function `bar` is never used
-  --> $DIR/lint-dead-code-1.rs:97:4
+  --> $DIR/lint-dead-code-1.rs:98:4
    |
 LL | fn bar() {
    |    ^^^
 
 error: function `baz` is never used
-  --> $DIR/lint-dead-code-1.rs:101:4
+  --> $DIR/lint-dead-code-1.rs:102:4
    |
 LL | fn baz() -> impl Copy {
    |    ^^^
@@ -79,5 +67,5 @@ error: struct `Bar` is never constructed
 LL |     pub struct Bar;
    |                ^^^
 
-error: aborting due to 12 previous errors
+error: aborting due to 10 previous errors
 

tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.rs

@@ -1,9 +1,8 @@
 #![deny(dead_code)]
 
 struct T1; //~ ERROR struct `T1` is never constructed
-struct T2; //~ ERROR struct `T2` is never constructed
-pub struct T3(i32); //~ ERROR struct `T3` is never constructed
-pub struct T4(i32); //~ ERROR field `0` is never read
+pub struct T2(i32); //~ ERROR field `0` is never read
+struct T3;
 
 trait Trait1 { //~ ERROR trait `Trait1` is never used
     const UNUSED: i32;
@@ -12,13 +11,13 @@ trait Trait1 { //~ ERROR trait `Trait1` is never used
 }
 
 pub trait Trait2 {
-    const MAY_USED: i32;
-    fn may_used(&self) {}
+    const USED: i32;
+    fn used(&self) {}
 }
 
 pub trait Trait3 {
-    const MAY_USED: i32;
-    fn may_used() -> Self;
+    const USED: i32;
+    fn construct_self() -> Self;
 }
 
 impl Trait1 for T1 {
@@ -31,34 +30,23 @@ impl Trait1 for T1 {
 impl Trait1 for T2 {
     const UNUSED: i32 = 0;
     fn construct_self() -> Self {
-        Self
+        T2(0)
     }
 }
 
 impl Trait2 for T1 {
-    const MAY_USED: i32 = 0;
+    const USED: i32 = 0;
 }
 
 impl Trait2 for T2 {
-    const MAY_USED: i32 = 0;
-}
-
-impl Trait2 for T3 {
-    const MAY_USED: i32 = 0;
+    const USED: i32 = 0;
 }
 
-impl Trait3 for T2 {
-    const MAY_USED: i32 = 0;
-    fn may_used() -> Self {
+impl Trait3 for T3 {
+    const USED: i32 = 0;
+    fn construct_self() -> Self {
         Self
     }
 }
 
-impl Trait3 for T4 {
-    const MAY_USED: i32 = 0;
-    fn may_used() -> Self {
-        T4(0)
-    }
-}
-
 fn main() {}

tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.stderr

@@ -10,33 +10,21 @@ note: the lint level is defined here
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^
 
-error: struct `T2` is never constructed
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:4:8
-   |
-LL | struct T2;
-   |        ^^
-
-error: struct `T3` is never constructed
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:5:12
-   |
-LL | pub struct T3(i32);
-   |            ^^
-
 error: field `0` is never read
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:6:15
+  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:4:15
    |
-LL | pub struct T4(i32);
+LL | pub struct T2(i32);
    |            -- ^^^
    |            |
    |            field in this struct
    |
    = help: consider removing this field
 
 error: trait `Trait1` is never used
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:8:7
+  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:7:7
    |
 LL | trait Trait1 {
    |       ^^^^^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 

tests/ui/lint/dead-code/unused-struct-derive-default.rs

@@ -22,5 +22,4 @@ pub struct T2 {
 
 fn main() {
     let _x: Used = Default::default();
-    let _e: E = Default::default();
 }

tests/ui/lint/dead-code/unused-struct-derive-default.stderr

@@ -4,6 +4,7 @@ error: struct `T` is never constructed
 LL | struct T;
    |        ^
    |
+   = note: `T` has a derived impl for the trait `Default`, but this is intentionally ignored during dead code analysis
 note: the lint level is defined here
   --> $DIR/unused-struct-derive-default.rs:1:9
    |

tests/ui/parser/issues/issue-105366.fixed

@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct Foo;
 
 impl From<i32> for Foo {

tests/ui/parser/issues/issue-105366.rs

@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct Foo;
 
 fn From<i32> for Foo {

tests/ui/parser/issues/issue-105366.stderr

@@ -1,5 +1,5 @@
 error: you might have meant to write `impl` instead of `fn`
-  --> $DIR/issue-105366.rs:6:1
+  --> $DIR/issue-105366.rs:5:1
    |
 LL | fn From<i32> for Foo {
    | ^^

tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed

@@ -1,8 +1,7 @@
 // Regression test for issues #100790 and #106439.
 //@ run-rustfix
 
-#[allow(dead_code)]
-pub struct Example(usize)
+pub struct Example(#[allow(dead_code)] usize)
 where
     (): Sized;
 //~^^^ ERROR where clauses are not allowed before tuple struct bodies

tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs

@@ -1,11 +1,10 @@
 // Regression test for issues #100790 and #106439.
 //@ run-rustfix
 
-#[allow(dead_code)]
 pub struct Example
 where
     (): Sized,
-(usize);
+(#[allow(dead_code)] usize);
 //~^^^ ERROR where clauses are not allowed before tuple struct bodies
 
 struct _Demo

tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr

@@ -1,23 +1,23 @@
 error: where clauses are not allowed before tuple struct bodies
-  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:6:1
+  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:5:1
    |
 LL |   pub struct Example
    |              ------- while parsing this tuple struct
 LL | / where
 LL | |     (): Sized,
    | |______________^ unexpected where clause
-LL |   (usize);
-   |   ------- the struct body
+LL |   (#[allow(dead_code)] usize);
+   |   --------------------------- the struct body
    |
 help: move the body before the where clause
    |
-LL ~ pub struct Example(usize)
+LL ~ pub struct Example(#[allow(dead_code)] usize)
 LL | where
 LL ~     (): Sized;
    |
 
 error: where clauses are not allowed before tuple struct bodies
-  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:12:1
+  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:11:1
    |
 LL |   struct _Demo
    |          ----- while parsing this tuple struct

tests/ui/pattern/issue-22546.rs

@@ -15,7 +15,7 @@ impl<T: ::std::fmt::Display> Foo<T> {
     }
 }
 
-trait Tr {
+trait Tr { //~ WARN trait `Tr` is never used
     type U;
 }
 

tests/ui/pattern/issue-22546.stderr

@@ -0,0 +1,10 @@
+warning: trait `Tr` is never used
+  --> $DIR/issue-22546.rs:18:7
+   |
+LL | trait Tr {
+   |       ^^
+   |
+   = note: `#[warn(dead_code)]` on by default
+
+warning: 1 warning emitted
+

tests/ui/pub/pub-ident-struct-4.fixed

@@ -1,7 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
-pub struct T(String);
+pub struct T(#[allow(dead_code)] String);
 //~^ ERROR missing `struct` for struct definition
 
 fn main() {}

tests/ui/pub/pub-ident-struct-4.rs

@@ -1,7 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
-pub T(String);
+pub T(#[allow(dead_code)] String);
 //~^ ERROR missing `struct` for struct definition
 
 fn main() {}

tests/ui/pub/pub-ident-struct-4.stderr

@@ -1,12 +1,12 @@
 error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-4.rs:4:1
+  --> $DIR/pub-ident-struct-4.rs:3:1
    |
-LL | pub T(String);
+LL | pub T(#[allow(dead_code)] String);
    | ^^^^^
    |
 help: add `struct` here to parse `T` as a struct
    |
-LL | pub struct T(String);
+LL | pub struct T(#[allow(dead_code)] String);
    |     ++++++
 
 error: aborting due to 1 previous error

tests/ui/regions/regions-issue-21422.rs

@@ -5,7 +5,6 @@
 
 //@ pretty-expanded FIXME #23616
 
-#[allow(dead_code)]
 pub struct P<'a> {
     _ptr: *const &'a u8,
 }

tests/ui/structs-enums/newtype-struct-with-dtor.rs

@@ -3,10 +3,8 @@
 #![allow(unused_variables)]
 //@ pretty-expanded FIXME #23616
 
-#[allow(dead_code)]
 pub struct Fd(u32);
 
-#[allow(dead_code)]
 fn foo(a: u32) {}
 
 impl Drop for Fd {

tests/ui/structs-enums/uninstantiable-struct.rs

@@ -1,5 +1,4 @@
 //@ run-pass
-#[allow(dead_code)]
-pub struct Z(&'static Z);
+pub struct Z(#[allow(dead_code)] &'static Z);
 
 pub fn main() {}

tests/ui/suggestions/derive-clone-for-eq.fixed

@@ -1,7 +1,6 @@
 //@ run-rustfix
 // https://github.com/rust-lang/rust/issues/79076
 
-#[allow(dead_code)]
 #[derive(Clone, Eq)] //~ ERROR [E0277]
 pub struct Struct<T: std::clone::Clone>(T);
 

tests/ui/suggestions/derive-clone-for-eq.rs

@@ -1,7 +1,6 @@
 //@ run-rustfix
 // https://github.com/rust-lang/rust/issues/79076
 
-#[allow(dead_code)]
 #[derive(Clone, Eq)] //~ ERROR [E0277]
 pub struct Struct<T>(T);
 

tests/ui/suggestions/derive-clone-for-eq.stderr

@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `T: Clone` is not satisfied
-  --> $DIR/derive-clone-for-eq.rs:5:17
+  --> $DIR/derive-clone-for-eq.rs:4:17
    |
 LL | #[derive(Clone, Eq)]
    |                 ^^ the trait `Clone` is not implemented for `T`, which is required by `Struct<T>: PartialEq`
    |
 note: required for `Struct<T>` to implement `PartialEq`
-  --> $DIR/derive-clone-for-eq.rs:8:19
+  --> $DIR/derive-clone-for-eq.rs:7:19
    |
 LL | impl<T: Clone, U> PartialEq<U> for Struct<T>
    |         -----     ^^^^^^^^^^^^     ^^^^^^^^^

tests/ui/suggestions/option-content-move.fixed

@@ -1,5 +1,4 @@
 //@ run-rustfix
-#[allow(dead_code)]
 pub struct LipogramCorpora {
     selections: Vec<(char, Option<String>)>,
 }
@@ -18,7 +17,6 @@ impl LipogramCorpora {
     }
 }
 
-#[allow(dead_code)]
 pub struct LipogramCorpora2 {
     selections: Vec<(char, Result<String, String>)>,
 }

tests/ui/suggestions/option-content-move.rs

@@ -1,5 +1,4 @@
 //@ run-rustfix
-#[allow(dead_code)]
 pub struct LipogramCorpora {
     selections: Vec<(char, Option<String>)>,
 }
@@ -18,7 +17,6 @@ impl LipogramCorpora {
     }
 }
 
-#[allow(dead_code)]
 pub struct LipogramCorpora2 {
     selections: Vec<(char, Result<String, String>)>,
 }

tests/ui/suggestions/option-content-move.stderr

@@ -1,5 +1,5 @@
 error[E0507]: cannot move out of `selection.1` which is behind a shared reference
-  --> $DIR/option-content-move.rs:11:20
+  --> $DIR/option-content-move.rs:10:20
    |
 LL |                 if selection.1.unwrap().contains(selection.0) {
    |                    ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
@@ -19,7 +19,7 @@ LL |                 if selection.1.clone().unwrap().contains(selection.0) {
    |                               ++++++++
 
 error[E0507]: cannot move out of `selection.1` which is behind a shared reference
-  --> $DIR/option-content-move.rs:30:20
+  --> $DIR/option-content-move.rs:28:20
    |
 LL |                 if selection.1.unwrap().contains(selection.0) {
    |                    ^^^^^^^^^^^ -------- `selection.1` moved due to this method call

tests/ui/traits/object/generics.rs

@@ -7,7 +7,6 @@ pub trait Trait2<A> {
     fn doit(&self) -> A;
 }
 
-#[allow(dead_code)]
 pub struct Impl<A1, A2, A3> {
     m1: marker::PhantomData<(A1,A2,A3)>,
     /*