From fd36553aa7b23455ac8431293fbdb0d6b760161c Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Mon, 18 Sep 2023 06:59:11 +0000 Subject: [PATCH] Don't complain on a single non-exhaustive 1-zst --- .../rustc_hir_analysis/src/check/check.rs | 48 +++++++++++-------- .../repr/repr-transparent-non-exhaustive.rs | 40 ++++++++++++++++ .../repr-transparent-non-exhaustive.stderr | 42 +++++++++++++++- 3 files changed, 110 insertions(+), 20 deletions(-) diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs index 1d381175c752e..13826264a224c 100644 --- a/compiler/rustc_hir_analysis/src/check/check.rs +++ b/compiler/rustc_hir_analysis/src/check/check.rs @@ -1201,25 +1201,35 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>) ); return; } - for (span, _trivial, non_exhaustive) in field_infos { - if let Some((descr, def_id, args, non_exhaustive)) = non_exhaustive { - tcx.struct_span_lint_hir( - REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS, - tcx.hir().local_def_id_to_hir_id(adt.did().expect_local()), - span, - "zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types", - |lint| { - let note = if non_exhaustive { - "is marked with `#[non_exhaustive]`" - } else { - "contains private fields" - }; - let field_ty = tcx.def_path_str_with_args(def_id, args); - lint - .note(format!("this {descr} contains `{field_ty}`, which {note}, \ - and makes it not a breaking change to become non-zero-sized in the future.")) - }, - ) + let mut prev_non_exhaustive_1zst = false; + for (span, _trivial, non_exhaustive_1zst) in field_infos { + if let Some((descr, def_id, args, non_exhaustive)) = non_exhaustive_1zst { + // If there are any non-trivial fields, then there can be no non-exhaustive 1-zsts. + // Otherwise, it's only an issue if there's >1 non-exhaustive 1-zst. + if non_trivial_count > 0 || prev_non_exhaustive_1zst { + tcx.struct_span_lint_hir( + REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS, + tcx.hir().local_def_id_to_hir_id(adt.did().expect_local()), + span, + "zero-sized fields in `repr(transparent)` cannot \ + contain external non-exhaustive types", + |lint| { + let note = if non_exhaustive { + "is marked with `#[non_exhaustive]`" + } else { + "contains private fields" + }; + let field_ty = tcx.def_path_str_with_args(def_id, args); + lint.note(format!( + "this {descr} contains `{field_ty}`, which {note}, \ + and makes it not a breaking change to become \ + non-zero-sized in the future." + )) + }, + ) + } else { + prev_non_exhaustive_1zst = true; + } } } } diff --git a/tests/ui/repr/repr-transparent-non-exhaustive.rs b/tests/ui/repr/repr-transparent-non-exhaustive.rs index 506f1dcf3fc51..84dd3f49239f2 100644 --- a/tests/ui/repr/repr-transparent-non-exhaustive.rs +++ b/tests/ui/repr/repr-transparent-non-exhaustive.rs @@ -93,4 +93,44 @@ pub struct T16(Sized, ExternalIndirection); //~^ ERROR zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types //~| WARN this was previously accepted by the compiler +#[repr(transparent)] +pub struct T17(NonExhaustive, Sized); +//~^ ERROR zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types +//~| WARN this was previously accepted by the compiler + +#[repr(transparent)] +pub struct T18(NonExhaustive, NonExhaustive); +//~^ ERROR zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types +//~| WARN this was previously accepted by the compiler + +#[repr(transparent)] +pub struct T19(NonExhaustive, Private); +//~^ ERROR zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types +//~| WARN this was previously accepted by the compiler + +#[repr(transparent)] +pub struct T19Flipped(Private, NonExhaustive); +//~^ ERROR zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types +//~| WARN this was previously accepted by the compiler + +#[repr(transparent)] +pub struct T20(NonExhaustive); +// Okay, since it's the only field. + +#[repr(transparent)] +pub struct T21(NonExhaustive, InternalNonExhaustive); +// Okay, since there's only 1 foreign non-exhaustive type. + +#[repr(transparent)] +pub struct T21Flipped(InternalNonExhaustive, NonExhaustive); +// Okay, since there's only 1 foreign non-exhaustive type. + +#[repr(transparent)] +pub struct T22(NonExhaustive, InternalPrivate); +// Okay, since there's only 1 foreign non-exhaustive type. + +#[repr(transparent)] +pub struct T22Flipped(InternalPrivate, NonExhaustive); +// Okay, since there's only 1 foreign non-exhaustive type. + fn main() {} diff --git a/tests/ui/repr/repr-transparent-non-exhaustive.stderr b/tests/ui/repr/repr-transparent-non-exhaustive.stderr index 16edf59c7cc34..808b9bc986d91 100644 --- a/tests/ui/repr/repr-transparent-non-exhaustive.stderr +++ b/tests/ui/repr/repr-transparent-non-exhaustive.stderr @@ -123,5 +123,45 @@ LL | pub struct T16(Sized, ExternalIndirection); = note: for more information, see issue #78586 = note: this enum contains `NonExhaustiveVariant`, which is marked with `#[non_exhaustive]`, and makes it not a breaking change to become non-zero-sized in the future. -error: aborting due to 12 previous errors +error: zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types + --> $DIR/repr-transparent-non-exhaustive.rs:97:16 + | +LL | pub struct T17(NonExhaustive, Sized); + | ^^^^^^^^^^^^^ + | + = 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 #78586 + = note: this struct contains `NonExhaustive`, which is marked with `#[non_exhaustive]`, and makes it not a breaking change to become non-zero-sized in the future. + +error: zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types + --> $DIR/repr-transparent-non-exhaustive.rs:102:31 + | +LL | pub struct T18(NonExhaustive, NonExhaustive); + | ^^^^^^^^^^^^^ + | + = 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 #78586 + = note: this struct contains `NonExhaustive`, which is marked with `#[non_exhaustive]`, and makes it not a breaking change to become non-zero-sized in the future. + +error: zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types + --> $DIR/repr-transparent-non-exhaustive.rs:107:31 + | +LL | pub struct T19(NonExhaustive, Private); + | ^^^^^^^ + | + = 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 #78586 + = note: this struct contains `Private`, which contains private fields, and makes it not a breaking change to become non-zero-sized in the future. + +error: zero-sized fields in `repr(transparent)` cannot contain external non-exhaustive types + --> $DIR/repr-transparent-non-exhaustive.rs:112:32 + | +LL | pub struct T19Flipped(Private, NonExhaustive); + | ^^^^^^^^^^^^^ + | + = 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 #78586 + = note: this struct contains `NonExhaustive`, which is marked with `#[non_exhaustive]`, and makes it not a breaking change to become non-zero-sized in the future. + +error: aborting due to 16 previous errors