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| diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs | |
| index 327e226a9f1..99430794668 100644 | |
| --- a/compiler/rustc_lint/src/types.rs | |
| +++ b/compiler/rustc_lint/src/types.rs | |
| @@ -940,30 +940,6 @@ pub(crate) fn repr_nullable_ptr<'tcx>( | |
| } | |
| impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { | |
| - // Returns `true` if `ty` is a `()`, or a `repr(transparent)` type whose only non-ZST field | |
| - // is a generic substituted for `()` - in either case, the type is FFI-safe when used as a | |
| - // return type. | |
| - pub fn is_unit_or_equivalent(&self, ty: Ty<'tcx>) -> bool { | |
| - if ty.is_unit() { | |
| - return true; | |
| - } | |
| - | |
| - if let ty::Adt(def, substs) = ty.kind() && def.repr().transparent() { | |
| - return def.variants() | |
| - .iter() | |
| - .filter_map(|variant| transparent_newtype_field(self.cx.tcx, variant)) | |
| - .all(|field| { | |
| - let field_ty = field.ty(self.cx.tcx, substs); | |
| - !field_ty.has_opaque_types() && { | |
| - let field_ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, field_ty); | |
| - self.is_unit_or_equivalent(field_ty) | |
| - } | |
| - }); | |
| - } | |
| - | |
| - false | |
| - } | |
| - | |
| /// Check if the type is array and emit an unsafe type lint. | |
| fn check_for_array_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { | |
| if let ty::Array(..) = ty.kind() { | |
| @@ -1007,14 +983,19 @@ fn check_variant_for_ffi( | |
| use FfiResult::*; | |
| let transparent_with_all_zst_fields = if def.repr().transparent() { | |
| - // Transparent newtypes have at most one non-ZST field which needs to be checked.. | |
| if let Some(field) = transparent_newtype_field(self.cx.tcx, variant) { | |
| - return self.check_field_type_for_ffi(cache, field, substs); | |
| - } | |
| + // Transparent newtypes have at most one non-ZST field which needs to be checked.. | |
| + match self.check_field_type_for_ffi(cache, field, substs) { | |
| + FfiUnsafe { ty, .. } if ty.is_unit() => (), | |
| + r => return r, | |
| + } | |
| - // ..or have only ZST fields, which is FFI-unsafe (unless those fields are all | |
| - // `PhantomData`). | |
| - true | |
| + false | |
| + } else { | |
| + // ..or have only ZST fields, which is FFI-unsafe (unless those fields are all | |
| + // `PhantomData`). | |
| + true | |
| + } | |
| } else { | |
| false | |
| }; | |
| @@ -1024,6 +1005,8 @@ fn check_variant_for_ffi( | |
| for field in &variant.fields { | |
| all_phantom &= match self.check_field_type_for_ffi(cache, &field, substs) { | |
| FfiSafe => false, | |
| + // `()` fields are FFI-safe! | |
| + FfiUnsafe { ty, .. } if ty.is_unit() => false, | |
| FfiPhantom(..) => true, | |
| r @ FfiUnsafe { .. } => return r, | |
| } | |
| @@ -1246,7 +1229,7 @@ fn check_type_for_ffi(&self, cache: &mut FxHashSet<Ty<'tcx>>, ty: Ty<'tcx>) -> F | |
| } | |
| let ret_ty = sig.output(); | |
| - if self.is_unit_or_equivalent(ret_ty) { | |
| + if ret_ty.is_unit() { | |
| return FfiSafe; | |
| } | |
| @@ -1371,7 +1354,7 @@ fn check_type_for_ffi_and_report_errors( | |
| // Don't report FFI errors for unit return types. This check exists here, and not in | |
| // the caller (where it would make more sense) so that normalization has definitely | |
| // happened. | |
| - if is_return_type && self.is_unit_or_equivalent(ty) { | |
| + if is_return_type && ty.is_unit() { | |
| return; | |
| } | |
| diff --git a/tests/ui/lint/lint-ctypes-113436.rs b/tests/ui/lint/lint-ctypes-113436.rs | |
| index d1328af9924..4f733b5bb16 100644 | |
| --- a/tests/ui/lint/lint-ctypes-113436.rs | |
| +++ b/tests/ui/lint/lint-ctypes-113436.rs | |
| @@ -1,3 +1,4 @@ | |
| +// check-pass | |
| #![deny(improper_ctypes_definitions)] | |
| #[repr(C)] | |
| @@ -7,20 +8,16 @@ | |
| pub struct TransparentWrap<T>(T); | |
| pub extern "C" fn f() -> Wrap<()> { | |
| - //~^ ERROR `extern` fn uses type `()`, which is not FFI-safe | |
| todo!() | |
| } | |
| const _: extern "C" fn() -> Wrap<()> = f; | |
| -//~^ ERROR `extern` fn uses type `()`, which is not FFI-safe | |
| pub extern "C" fn ff() -> Wrap<Wrap<()>> { | |
| - //~^ ERROR `extern` fn uses type `()`, which is not FFI-safe | |
| todo!() | |
| } | |
| const _: extern "C" fn() -> Wrap<Wrap<()>> = ff; | |
| -//~^ ERROR `extern` fn uses type `()`, which is not FFI-safe | |
| pub extern "C" fn g() -> TransparentWrap<()> { | |
| todo!() | |
| diff --git a/tests/ui/lint/lint-ctypes-113436.stderr b/tests/ui/lint/lint-ctypes-113436.stderr | |
| deleted file mode 100644 | |
| index 72f92c1a49c..00000000000 | |
| --- a/tests/ui/lint/lint-ctypes-113436.stderr | |
| +++ /dev/null | |
| @@ -1,43 +0,0 @@ | |
| -error: `extern` fn uses type `()`, which is not FFI-safe | |
| - --> $DIR/lint-ctypes-113436.rs:9:26 | |
| - | | |
| -LL | pub extern "C" fn f() -> Wrap<()> { | |
| - | ^^^^^^^^ not FFI-safe | |
| - | | |
| - = help: consider using a struct instead | |
| - = note: tuples have unspecified layout | |
| -note: the lint level is defined here | |
| - --> $DIR/lint-ctypes-113436.rs:1:9 | |
| - | | |
| -LL | #![deny(improper_ctypes_definitions)] | |
| - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
| - | |
| -error: `extern` fn uses type `()`, which is not FFI-safe | |
| - --> $DIR/lint-ctypes-113436.rs:14:10 | |
| - | | |
| -LL | const _: extern "C" fn() -> Wrap<()> = f; | |
| - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe | |
| - | | |
| - = help: consider using a struct instead | |
| - = note: tuples have unspecified layout | |
| - | |
| -error: `extern` fn uses type `()`, which is not FFI-safe | |
| - --> $DIR/lint-ctypes-113436.rs:17:27 | |
| - | | |
| -LL | pub extern "C" fn ff() -> Wrap<Wrap<()>> { | |
| - | ^^^^^^^^^^^^^^ not FFI-safe | |
| - | | |
| - = help: consider using a struct instead | |
| - = note: tuples have unspecified layout | |
| - | |
| -error: `extern` fn uses type `()`, which is not FFI-safe | |
| - --> $DIR/lint-ctypes-113436.rs:22:10 | |
| - | | |
| -LL | const _: extern "C" fn() -> Wrap<Wrap<()>> = ff; | |
| - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe | |
| - | | |
| - = help: consider using a struct instead | |
| - = note: tuples have unspecified layout | |
| - | |
| -error: aborting due to 4 previous errors | |
| - | |
| diff --git a/tests/ui/repr/repr-transparent-issue-87496.rs b/tests/ui/repr/repr-transparent-issue-87496.rs | |
| index 0ce6fb2c19f..a4dd45c63f5 100644 | |
| --- a/tests/ui/repr/repr-transparent-issue-87496.rs | |
| +++ b/tests/ui/repr/repr-transparent-issue-87496.rs | |
| @@ -6,7 +6,7 @@ | |
| struct TransparentCustomZst(()); | |
| extern "C" { | |
| fn good17(p: TransparentCustomZst); | |
| - //~^ WARNING: `extern` block uses type `()`, which is not FFI-safe | |
| + //~^ WARNING: `extern` block uses type `TransparentCustomZst`, which is not FFI-safe | |
| } | |
| fn main() {} | |
| diff --git a/tests/ui/repr/repr-transparent-issue-87496.stderr b/tests/ui/repr/repr-transparent-issue-87496.stderr | |
| index 03c62f8514e..aee31212b4e 100644 | |
| --- a/tests/ui/repr/repr-transparent-issue-87496.stderr | |
| +++ b/tests/ui/repr/repr-transparent-issue-87496.stderr | |
| @@ -1,11 +1,15 @@ | |
| -warning: `extern` block uses type `()`, which is not FFI-safe | |
| +warning: `extern` block uses type `TransparentCustomZst`, which is not FFI-safe | |
| --> $DIR/repr-transparent-issue-87496.rs:8:18 | |
| | | |
| LL | fn good17(p: TransparentCustomZst); | |
| | ^^^^^^^^^^^^^^^^^^^^ not FFI-safe | |
| | | |
| - = help: consider using a struct instead | |
| - = note: tuples have unspecified layout | |
| + = note: this struct contains only zero-sized fields | |
| +note: the type is defined here | |
| + --> $DIR/repr-transparent-issue-87496.rs:6:1 | |
| + | | |
| +LL | struct TransparentCustomZst(()); | |
| + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
| = note: `#[warn(improper_ctypes)]` on by default | |
| warning: 1 warning emitted |
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