diff options
| -rw-r--r-- | compiler/rustc_mir_transform/src/check_packed_ref.rs | 13 | ||||
| -rw-r--r-- | src/test/ui/derives/deriving-with-repr-packed.rs | 38 | ||||
| -rw-r--r-- | src/test/ui/derives/deriving-with-repr-packed.stderr | 68 |
3 files changed, 68 insertions, 51 deletions
diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs index 2eb38941f1a..c21c1efe991 100644 --- a/compiler/rustc_mir_transform/src/check_packed_ref.rs +++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs @@ -36,13 +36,16 @@ fn unsafe_derive_on_repr_packed(tcx: TyCtxt<'_>, def_id: LocalDefId) { tcx.struct_span_lint_hir(UNALIGNED_REFERENCES, lint_hir_id, tcx.def_span(def_id), |lint| { // FIXME: when we make this a hard error, this should have its // own error code. - let message = if tcx.generics_of(def_id).own_requires_monomorphization() { - "`#[derive]` can't be used on a `#[repr(packed)]` struct with \ - type or const parameters (error E0133)" + let extra = if tcx.generics_of(def_id).own_requires_monomorphization() { + "with type or const parameters" } else { - "`#[derive]` can't be used on a `#[repr(packed)]` struct that \ - does not derive Copy (error E0133)" + "that does not derive `Copy`" }; + let message = format!( + "`{}` can't be derived on this `#[repr(packed)]` struct {} (error E0133)", + tcx.item_name(tcx.trait_id_of_impl(def_id.to_def_id()).expect("derived trait name")), + extra + ); lint.build(message).emit(); }); } diff --git a/src/test/ui/derives/deriving-with-repr-packed.rs b/src/test/ui/derives/deriving-with-repr-packed.rs index b78eeaa9055..3884e397764 100644 --- a/src/test/ui/derives/deriving-with-repr-packed.rs +++ b/src/test/ui/derives/deriving-with-repr-packed.rs @@ -1,29 +1,43 @@ #![deny(unaligned_references)] -// check that derive on a packed struct with non-Copy fields -// correctly. This can't be made to work perfectly because -// we can't just use the field from the struct as it might -// not be aligned. +// Check that deriving certain builtin traits on certain packed structs cause +// errors. This happens when the derived trait would need to use a potentially +// misaligned reference. But there are two cases that are allowed: +// - If all the fields within the struct meet the required alignment: 1 for +// `repr(packed)`, or `N` for `repr(packed(N))`. +// - If `Default` is the only trait derived, because it doesn't involve any +// references. -#[derive(Copy, Clone, PartialEq, Eq)] -//~^ ERROR `#[derive]` can't be used +#[derive(Copy, Clone, Default, PartialEq, Eq)] +//~^ ERROR `Clone` can't be derived on this `#[repr(packed)]` struct with type or const parameters //~| hard error -//~^^^ ERROR `#[derive]` can't be used +//~^^^ ERROR `PartialEq` can't be derived on this `#[repr(packed)]` struct with type or const parameters //~| hard error #[repr(packed)] pub struct Foo<T>(T, T, T); -#[derive(PartialEq, Eq)] -//~^ ERROR `#[derive]` can't be used +#[derive(Default, Hash)] +//~^ ERROR `Hash` can't be derived on this `#[repr(packed)]` struct that does not derive `Copy` //~| hard error #[repr(packed)] pub struct Bar(u32, u32, u32); -#[derive(PartialEq)] +// This one is fine because the field alignment is 1. +#[derive(Default, Hash)] +#[repr(packed)] +pub struct Bar2(u8, i8, bool); + +// This one is fine because the field alignment is 2, matching `packed(2)`. +#[derive(Default, Hash)] +#[repr(packed(2))] +pub struct Bar3(u16, i16, bool); + +// This one is fine because it's not packed. +#[derive(Debug, Default)] struct Y(usize); -#[derive(PartialEq)] -//~^ ERROR `#[derive]` can't be used +#[derive(Debug, Default)] +//~^ ERROR `Debug` can't be derived on this `#[repr(packed)]` struct that does not derive `Copy` //~| hard error #[repr(packed)] struct X(Y); diff --git a/src/test/ui/derives/deriving-with-repr-packed.stderr b/src/test/ui/derives/deriving-with-repr-packed.stderr index 1002b359f60..1f98da5b70e 100644 --- a/src/test/ui/derives/deriving-with-repr-packed.stderr +++ b/src/test/ui/derives/deriving-with-repr-packed.stderr @@ -1,7 +1,7 @@ -error: `#[derive]` can't be used on a `#[repr(packed)]` struct with type or const parameters (error E0133) - --> $DIR/deriving-with-repr-packed.rs:8:16 +error: `Clone` can't be derived on this `#[repr(packed)]` struct with type or const parameters (error E0133) + --> $DIR/deriving-with-repr-packed.rs:11:16 | -LL | #[derive(Copy, Clone, PartialEq, Eq)] +LL | #[derive(Copy, Clone, Default, PartialEq, Eq)] | ^^^^^ | note: the lint level is defined here @@ -13,43 +13,43 @@ LL | #![deny(unaligned_references)] = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523> = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info) -error: `#[derive]` can't be used on a `#[repr(packed)]` struct with type or const parameters (error E0133) - --> $DIR/deriving-with-repr-packed.rs:8:23 +error: `PartialEq` can't be derived on this `#[repr(packed)]` struct with type or const parameters (error E0133) + --> $DIR/deriving-with-repr-packed.rs:11:32 | -LL | #[derive(Copy, Clone, PartialEq, Eq)] - | ^^^^^^^^^ +LL | #[derive(Copy, Clone, Default, PartialEq, Eq)] + | ^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523> = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info) -error: `#[derive]` can't be used on a `#[repr(packed)]` struct that does not derive Copy (error E0133) - --> $DIR/deriving-with-repr-packed.rs:16:10 +error: `Hash` can't be derived on this `#[repr(packed)]` struct that does not derive `Copy` (error E0133) + --> $DIR/deriving-with-repr-packed.rs:19:19 | -LL | #[derive(PartialEq, Eq)] - | ^^^^^^^^^ +LL | #[derive(Default, Hash)] + | ^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523> - = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info) + = note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info) -error: `#[derive]` can't be used on a `#[repr(packed)]` struct that does not derive Copy (error E0133) - --> $DIR/deriving-with-repr-packed.rs:25:10 +error: `Debug` can't be derived on this `#[repr(packed)]` struct that does not derive `Copy` (error E0133) + --> $DIR/deriving-with-repr-packed.rs:39:10 | -LL | #[derive(PartialEq)] - | ^^^^^^^^^ +LL | #[derive(Debug, Default)] + | ^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523> - = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info) + = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 4 previous errors Future incompatibility report: Future breakage diagnostic: -error: `#[derive]` can't be used on a `#[repr(packed)]` struct with type or const parameters (error E0133) - --> $DIR/deriving-with-repr-packed.rs:8:16 +error: `Clone` can't be derived on this `#[repr(packed)]` struct with type or const parameters (error E0133) + --> $DIR/deriving-with-repr-packed.rs:11:16 | -LL | #[derive(Copy, Clone, PartialEq, Eq)] +LL | #[derive(Copy, Clone, Default, PartialEq, Eq)] | ^^^^^ | note: the lint level is defined here @@ -62,11 +62,11 @@ LL | #![deny(unaligned_references)] = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info) Future breakage diagnostic: -error: `#[derive]` can't be used on a `#[repr(packed)]` struct with type or const parameters (error E0133) - --> $DIR/deriving-with-repr-packed.rs:8:23 +error: `PartialEq` can't be derived on this `#[repr(packed)]` struct with type or const parameters (error E0133) + --> $DIR/deriving-with-repr-packed.rs:11:32 | -LL | #[derive(Copy, Clone, PartialEq, Eq)] - | ^^^^^^^^^ +LL | #[derive(Copy, Clone, Default, PartialEq, Eq)] + | ^^^^^^^^^ | note: the lint level is defined here --> $DIR/deriving-with-repr-packed.rs:1:9 @@ -78,11 +78,11 @@ LL | #![deny(unaligned_references)] = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info) Future breakage diagnostic: -error: `#[derive]` can't be used on a `#[repr(packed)]` struct that does not derive Copy (error E0133) - --> $DIR/deriving-with-repr-packed.rs:16:10 +error: `Hash` can't be derived on this `#[repr(packed)]` struct that does not derive `Copy` (error E0133) + --> $DIR/deriving-with-repr-packed.rs:19:19 | -LL | #[derive(PartialEq, Eq)] - | ^^^^^^^^^ +LL | #[derive(Default, Hash)] + | ^^^^ | note: the lint level is defined here --> $DIR/deriving-with-repr-packed.rs:1:9 @@ -91,14 +91,14 @@ LL | #![deny(unaligned_references)] | ^^^^^^^^^^^^^^^^^^^^ = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523> - = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info) + = note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info) Future breakage diagnostic: -error: `#[derive]` can't be used on a `#[repr(packed)]` struct that does not derive Copy (error E0133) - --> $DIR/deriving-with-repr-packed.rs:25:10 +error: `Debug` can't be derived on this `#[repr(packed)]` struct that does not derive `Copy` (error E0133) + --> $DIR/deriving-with-repr-packed.rs:39:10 | -LL | #[derive(PartialEq)] - | ^^^^^^^^^ +LL | #[derive(Debug, Default)] + | ^^^^^ | note: the lint level is defined here --> $DIR/deriving-with-repr-packed.rs:1:9 @@ -107,5 +107,5 @@ LL | #![deny(unaligned_references)] | ^^^^^^^^^^^^^^^^^^^^ = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #82523 <https://github.com/rust-lang/rust/issues/82523> - = note: this error originates in the derive macro `PartialEq` (in Nightly builds, run with -Z macro-backtrace for more info) + = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info) |