diff --git a/compiler/rustc_hir_analysis/locales/en-US.ftl b/compiler/rustc_hir_analysis/locales/en-US.ftl index 50e857ef60d..44580a46853 100644 --- a/compiler/rustc_hir_analysis/locales/en-US.ftl +++ b/compiler/rustc_hir_analysis/locales/en-US.ftl @@ -163,3 +163,10 @@ hir_analysis_pass_to_variadic_function = can't pass `{$ty}` to variadic function .help = cast the value to `{$cast_ty}` hir_analysis_cast_thin_pointer_to_fat_pointer = cannot cast thin pointer `{$expr_ty}` to fat pointer `{$cast_ty}` + +hir_analysis_invalid_union_field = + field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union + .note = union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` + +hir_analysis_invalid_union_field_sugg = + wrap the field type in `ManuallyDrop<...>` diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs index 3449d3d439d..be0ae4ce2ef 100644 --- a/compiler/rustc_hir_analysis/src/check/check.rs +++ b/compiler/rustc_hir_analysis/src/check/check.rs @@ -1,5 +1,5 @@ use crate::check::intrinsicck::InlineAsmCtxt; -use crate::errors::LinkageType; +use crate::errors::{self, LinkageType}; use super::compare_impl_item::check_type_bounds; use super::compare_impl_item::{compare_impl_method, compare_impl_ty}; @@ -114,9 +114,11 @@ fn allowed_union_field<'tcx>( allowed_union_field(*elem, tcx, param_env) } _ => { - // Fallback case: allow `ManuallyDrop` and things that are `Copy`. + // Fallback case: allow `ManuallyDrop` and things that are `Copy`, + // also no need to report an error if the type is unresolved. ty.ty_adt_def().is_some_and(|adt_def| adt_def.is_manually_drop()) || ty.is_copy_modulo_regions(tcx, param_env) + || ty.references_error() } } } @@ -131,26 +133,14 @@ fn allowed_union_field<'tcx>( Some(Node::Field(field)) => (field.span, field.ty.span), _ => unreachable!("mir field has to correspond to hir field"), }; - struct_span_err!( - tcx.sess, + tcx.sess.emit_err(errors::InvalidUnionField { field_span, - E0740, - "unions cannot contain fields that may need dropping" - ) - .note( - "a type is guaranteed not to need dropping \ - when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type", - ) - .multipart_suggestion_verbose( - "when the type does not implement `Copy`, \ - wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped", - vec![ - (ty_span.shrink_to_lo(), "std::mem::ManuallyDrop<".into()), - (ty_span.shrink_to_hi(), ">".into()), - ], - Applicability::MaybeIncorrect, - ) - .emit(); + sugg: errors::InvalidUnionFieldSuggestion { + lo: ty_span.shrink_to_lo(), + hi: ty_span.shrink_to_hi(), + }, + note: (), + }); return false; } else if field_ty.needs_drop(tcx, param_env) { // This should never happen. But we can get here e.g. in case of name resolution errors. diff --git a/compiler/rustc_hir_analysis/src/errors.rs b/compiler/rustc_hir_analysis/src/errors.rs index 74fec93d91e..dd40706f1d3 100644 --- a/compiler/rustc_hir_analysis/src/errors.rs +++ b/compiler/rustc_hir_analysis/src/errors.rs @@ -5,7 +5,7 @@ error_code, Applicability, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, MultiSpan, }; -use rustc_macros::Diagnostic; +use rustc_macros::{Diagnostic, Subdiagnostic}; use rustc_middle::ty::Ty; use rustc_span::{symbol::Ident, Span, Symbol}; @@ -430,3 +430,23 @@ pub(crate) struct CastThinPointerToFatPointer<'tcx> { pub expr_ty: Ty<'tcx>, pub cast_ty: String, } + +#[derive(Diagnostic)] +#[diag(hir_analysis_invalid_union_field, code = "E0740")] +pub(crate) struct InvalidUnionField { + #[primary_span] + pub field_span: Span, + #[subdiagnostic] + pub sugg: InvalidUnionFieldSuggestion, + #[note] + pub note: (), +} + +#[derive(Subdiagnostic)] +#[multipart_suggestion(hir_analysis_invalid_union_field_sugg, applicability = "machine-applicable")] +pub(crate) struct InvalidUnionFieldSuggestion { + #[suggestion_part(code = "std::mem::ManuallyDrop<")] + pub lo: Span, + #[suggestion_part(code = ">")] + pub hi: Span, +} diff --git a/tests/ui/union/field_checks.rs b/tests/ui/union/field_checks.rs index d5d1e44ac85..bb4eccb4cf8 100644 --- a/tests/ui/union/field_checks.rs +++ b/tests/ui/union/field_checks.rs @@ -21,15 +21,15 @@ union U24 { // OK } union U3 { - a: String, //~ ERROR unions cannot contain fields that may need dropping + a: String, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } union U32 { // field that does not drop but is not `Copy`, either - a: std::cell::RefCell, //~ ERROR unions cannot contain fields that may need dropping + a: std::cell::RefCell, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } union U4 { - a: T, //~ ERROR unions cannot contain fields that may need dropping + a: T, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } union U5 { // Having a drop impl is OK @@ -41,11 +41,11 @@ fn drop(&mut self) {} } union U5Nested { // a nested union that drops is NOT OK - nest: U5, //~ ERROR unions cannot contain fields that may need dropping + nest: U5, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } union U5Nested2 { // for now we don't special-case empty arrays - nest: [U5; 0], //~ ERROR unions cannot contain fields that may need dropping + nest: [U5; 0], //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } union U6 { // OK diff --git a/tests/ui/union/field_checks.stderr b/tests/ui/union/field_checks.stderr index 1f97e97ac6e..32407a74970 100644 --- a/tests/ui/union/field_checks.stderr +++ b/tests/ui/union/field_checks.stderr @@ -1,59 +1,59 @@ -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/field_checks.rs:24:5 | LL | a: String, | ^^^^^^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/field_checks.rs:28:5 | LL | a: std::cell::RefCell, | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop>, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/field_checks.rs:32:5 | LL | a: T, | ^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/field_checks.rs:44:5 | LL | nest: U5, | ^^^^^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | nest: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/field_checks.rs:48:5 | LL | nest: [U5; 0], | ^^^^^^^^^^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | nest: std::mem::ManuallyDrop<[U5; 0]>, | +++++++++++++++++++++++ + diff --git a/tests/ui/union/issue-41073.rs b/tests/ui/union/issue-41073.rs index 4dfdc606bb4..f7a82b4e7cf 100644 --- a/tests/ui/union/issue-41073.rs +++ b/tests/ui/union/issue-41073.rs @@ -1,5 +1,5 @@ union Test { - a: A, //~ ERROR unions cannot contain fields that may need dropping + a: A, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union b: B } diff --git a/tests/ui/union/issue-41073.stderr b/tests/ui/union/issue-41073.stderr index b3887fa0f90..ae1c4dfed9a 100644 --- a/tests/ui/union/issue-41073.stderr +++ b/tests/ui/union/issue-41073.stderr @@ -1,11 +1,11 @@ -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/issue-41073.rs:2:5 | LL | a: A, | ^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + diff --git a/tests/ui/union/union-with-drop-fields.mirunsafeck.stderr b/tests/ui/union/union-with-drop-fields.mirunsafeck.stderr index 93fe996d2a4..9861a21cb3d 100644 --- a/tests/ui/union/union-with-drop-fields.mirunsafeck.stderr +++ b/tests/ui/union/union-with-drop-fields.mirunsafeck.stderr @@ -1,35 +1,35 @@ -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/union-with-drop-fields.rs:11:5 | LL | a: String, | ^^^^^^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/union-with-drop-fields.rs:19:5 | LL | a: S, | ^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/union-with-drop-fields.rs:24:5 | LL | a: T, | ^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + diff --git a/tests/ui/union/union-with-drop-fields.rs b/tests/ui/union/union-with-drop-fields.rs index a7a8b69e784..9720830fb1f 100644 --- a/tests/ui/union/union-with-drop-fields.rs +++ b/tests/ui/union/union-with-drop-fields.rs @@ -8,7 +8,7 @@ union U { } union W { - a: String, //~ ERROR unions cannot contain fields that may need dropping + a: String, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union b: String, // OK, only one field is reported } @@ -16,12 +16,12 @@ union W { // `S` doesn't implement `Drop` trait, but still has non-trivial destructor union Y { - a: S, //~ ERROR unions cannot contain fields that may need dropping + a: S, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } // We don't know if `T` is trivially-destructable or not until trans union J { - a: T, //~ ERROR unions cannot contain fields that may need dropping + a: T, //~ ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union } union H { diff --git a/tests/ui/union/union-with-drop-fields.thirunsafeck.stderr b/tests/ui/union/union-with-drop-fields.thirunsafeck.stderr index 93fe996d2a4..9861a21cb3d 100644 --- a/tests/ui/union/union-with-drop-fields.thirunsafeck.stderr +++ b/tests/ui/union/union-with-drop-fields.thirunsafeck.stderr @@ -1,35 +1,35 @@ -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/union-with-drop-fields.rs:11:5 | LL | a: String, | ^^^^^^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/union-with-drop-fields.rs:19:5 | LL | a: S, | ^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + -error[E0740]: unions cannot contain fields that may need dropping +error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union --> $DIR/union-with-drop-fields.rs:24:5 | LL | a: T, | ^^^^ | - = note: a type is guaranteed not to need dropping when it implements `Copy`, or when it is the special `ManuallyDrop<_>` type -help: when the type does not implement `Copy`, wrap it inside a `ManuallyDrop<_>` and ensure it is manually dropped + = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>` +help: wrap the field type in `ManuallyDrop<...>` | LL | a: std::mem::ManuallyDrop, | +++++++++++++++++++++++ + diff --git a/tests/ui/union/unresolved-field-isnt-copy.rs b/tests/ui/union/unresolved-field-isnt-copy.rs new file mode 100644 index 00000000000..7a6d79b2faa --- /dev/null +++ b/tests/ui/union/unresolved-field-isnt-copy.rs @@ -0,0 +1,8 @@ +// Unresolved fields are not copy, but also shouldn't report an extra E0740. + +pub union Foo { + x: *const Missing, + //~^ ERROR cannot find type `Missing` in this scope +} + +fn main() {} diff --git a/tests/ui/union/unresolved-field-isnt-copy.stderr b/tests/ui/union/unresolved-field-isnt-copy.stderr new file mode 100644 index 00000000000..22301582eef --- /dev/null +++ b/tests/ui/union/unresolved-field-isnt-copy.stderr @@ -0,0 +1,9 @@ +error[E0412]: cannot find type `Missing` in this scope + --> $DIR/unresolved-field-isnt-copy.rs:4:15 + | +LL | x: *const Missing, + | ^^^^^^^ not found in this scope + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0412`.