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Fix transmute_undefined_repr when converting between a pointer and a type containing a pointer

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This commit is contained in:
Jason Newcomb 2022-02-15 11:29:02 -05:00
parent 73367f8768
commit c02dff7167
3 changed files with 39 additions and 4 deletions
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3
clippy_lints/src/transmute/transmute_undefined_repr.rs
View file

@ -273,7 +273,8 @@ fn reduce_ty<'tcx>(cx: &LateContext<'tcx>, mut ty: Ty<'tcx>) -> ReducedTy<'tcx>
ReducedTy::UnorderedFields(ty)
}
},
ty::Ref(..) | ty::RawPtr(_) => ReducedTy::Ref(ty),
ty::Ref(_, ty, _) => ReducedTy::Ref(ty),
ty::RawPtr(ty) => ReducedTy::Ref(ty.ty),
_ => ReducedTy::Other(ty),
};
}

14
tests/ui/transmute_undefined_repr.rs
View file

@ -44,5 +44,19 @@ fn main() {
// issue #8417
let _: Ty2C<Ty2<u32, i32>, ()> = core::mem::transmute(value::<Ty2<u32, i32>>()); // Ok, Ty2 types are the same
let _: Ty2<u32, i32> = core::mem::transmute(value::<Ty2C<Ty2<u32, i32>, ()>>()); // Ok, Ty2 types are the same
// Ty2 types are the same
let _: &'static mut Ty2<u32, u32> = core::mem::transmute(value::<Box<Ty2<u32, u32>>>()); // Ok
// Ty2 types are the same
let _: Box<Ty2<u32, u32>> = core::mem::transmute(value::<&'static mut Ty2<u32, u32>>()); // Ok
let _: *mut Ty2<u32, u32> = core::mem::transmute(value::<Box<Ty2<u32, u32>>>()); // Ok, Ty2 types are the same
let _: Box<Ty2<u32, u32>> = core::mem::transmute(value::<*mut Ty2<u32, u32>>()); // Ok, Ty2 types are the same
// Different Ty2 instances
let _: &'static mut Ty2<u32, f32> = core::mem::transmute(value::<Box<Ty2<u32, u32>>>()); // Lint
// Different Ty2 instances
let _: Box<Ty2<u32, u32>> = core::mem::transmute(value::<&'static mut Ty2<u32, f32>>()); // Lint
}
}

26
tests/ui/transmute_undefined_repr.stderr
View file

@ -28,17 +28,37 @@ LL | let _: Ty<Ty2<u32, i32>> = core::mem::transmute(value::<Ty2<u32, f3
|
= note: two instances of the same generic type (`Ty2`) may have different layouts
error: transmute to `&Ty2<u32, f32>` which has an undefined layout
error: transmute from `Ty<&Ty2<u32, i32>>` to `&Ty2<u32, f32>`, both of which have an undefined layout
--> $DIR/transmute_undefined_repr.rs:35:33
|
LL | let _: &Ty2<u32, f32> = core::mem::transmute(value::<Ty<&Ty2<u32, i32>>>()); // Lint, different Ty2 instances
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: two instances of the same generic type (`Ty2`) may have different layouts
error: transmute from `&Ty2<u32, f32>` which has an undefined layout
error: transmute from `&Ty2<u32, f32>` to `Ty<&Ty2<u32, i32>>`, both of which have an undefined layout
--> $DIR/transmute_undefined_repr.rs:36:37
|
LL | let _: Ty<&Ty2<u32, i32>> = core::mem::transmute(value::<&Ty2<u32, f32>>()); // Lint, different Ty2 instances
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: two instances of the same generic type (`Ty2`) may have different layouts
error: aborting due to 6 previous errors
error: transmute from `std::boxed::Box<Ty2<u32, u32>>` to `&mut Ty2<u32, f32>`, both of which have an undefined layout
--> $DIR/transmute_undefined_repr.rs:56:45
|
LL | let _: &'static mut Ty2<u32, f32> = core::mem::transmute(value::<Box<Ty2<u32, u32>>>()); // Lint
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: two instances of the same generic type (`Ty2`) may have different layouts
error: transmute from `&mut Ty2<u32, f32>` to `std::boxed::Box<Ty2<u32, u32>>`, both of which have an undefined layout
--> $DIR/transmute_undefined_repr.rs:58:37
|
LL | let _: Box<Ty2<u32, u32>> = core::mem::transmute(value::<&'static mut Ty2<u32, f32>>()); // Lint
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: two instances of the same generic type (`Ty2`) may have different layouts
error: aborting due to 8 previous errors