diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs index 9422a594488..d7f17ac4547 100644 --- a/compiler/rustc_passes/src/dead.rs +++ b/compiler/rustc_passes/src/dead.rs @@ -57,7 +57,7 @@ struct MarkSymbolVisitor<'tcx> { tcx: TyCtxt<'tcx>, maybe_typeck_results: Option<&'tcx ty::TypeckResults<'tcx>>, live_symbols: LocalDefIdSet, - repr_has_repr_c: bool, + repr_unconditionally_treats_fields_as_live: bool, repr_has_repr_simd: bool, in_pat: bool, ignore_variant_stack: Vec, @@ -365,15 +365,17 @@ impl<'tcx> MarkSymbolVisitor<'tcx> { return; } - let had_repr_c = self.repr_has_repr_c; + let unconditionally_treated_fields_as_live = + self.repr_unconditionally_treats_fields_as_live; let had_repr_simd = self.repr_has_repr_simd; - self.repr_has_repr_c = false; + self.repr_unconditionally_treats_fields_as_live = false; self.repr_has_repr_simd = false; match node { Node::Item(item) => match item.kind { hir::ItemKind::Struct(..) | hir::ItemKind::Union(..) => { let def = self.tcx.adt_def(item.owner_id); - self.repr_has_repr_c = def.repr().c(); + self.repr_unconditionally_treats_fields_as_live = + def.repr().c() || def.repr().transparent(); self.repr_has_repr_simd = def.repr().simd(); intravisit::walk_item(self, item) @@ -411,7 +413,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> { _ => {} } self.repr_has_repr_simd = had_repr_simd; - self.repr_has_repr_c = had_repr_c; + self.repr_unconditionally_treats_fields_as_live = unconditionally_treated_fields_as_live; } fn mark_as_used_if_union(&mut self, adt: ty::AdtDef<'tcx>, fields: &[hir::ExprField<'_>]) { @@ -435,11 +437,11 @@ impl<'tcx> Visitor<'tcx> for MarkSymbolVisitor<'tcx> { fn visit_variant_data(&mut self, def: &'tcx hir::VariantData<'tcx>) { let tcx = self.tcx; - let has_repr_c = self.repr_has_repr_c; + let unconditionally_treat_fields_as_live = self.repr_unconditionally_treats_fields_as_live; let has_repr_simd = self.repr_has_repr_simd; let live_fields = def.fields().iter().filter_map(|f| { let def_id = f.def_id; - if has_repr_c || (f.is_positional() && has_repr_simd) { + if unconditionally_treat_fields_as_live || (f.is_positional() && has_repr_simd) { return Some(def_id); } if !tcx.visibility(f.hir_id.owner.def_id).is_public() { @@ -741,7 +743,7 @@ fn live_symbols_and_ignored_derived_traits( tcx, maybe_typeck_results: None, live_symbols: Default::default(), - repr_has_repr_c: false, + repr_unconditionally_treats_fields_as_live: false, repr_has_repr_simd: false, in_pat: false, ignore_variant_stack: vec![], diff --git a/tests/ui/lint/dead-code/type-in-transparent.rs b/tests/ui/lint/dead-code/type-in-transparent.rs new file mode 100644 index 00000000000..5dd6f93fd03 --- /dev/null +++ b/tests/ui/lint/dead-code/type-in-transparent.rs @@ -0,0 +1,14 @@ +// Verify that we do not warn on fields that are part of transparent types. +// check-pass +#![deny(dead_code)] + +#[repr(transparent)] +struct NamedStruct { field: u8 } + +#[repr(transparent)] +struct TupleStruct(u8); + +fn main() { + let _ = NamedStruct { field: 1 }; + let _ = TupleStruct(1); +}