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Make TAITs capture all higher-ranked lifetimes in scope

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This commit is contained in:
Michael Goulet 2024-03-06 17:52:53 +00:00
parent 9823f17315
commit cf299ddb6e
17 changed files with 122 additions and 152 deletions
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10
compiler/rustc_hir_analysis/src/variance/mod.rs
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@ -125,15 +125,7 @@ fn variance_of_opaque(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[ty::Varianc
// By default, RPIT are invariant wrt type and const generics, but they are bivariant wrt
// lifetime generics.
let variances = std::iter::repeat(ty::Invariant).take(generics.count());
let mut variances: Vec<_> = match tcx.opaque_type_origin(item_def_id) {
rustc_hir::OpaqueTyOrigin::FnReturn(_) | rustc_hir::OpaqueTyOrigin::AsyncFn(_) => {
variances.collect()
}
// But TAIT are invariant for all generics
rustc_hir::OpaqueTyOrigin::TyAlias { .. } => return tcx.arena.alloc_from_iter(variances),
};
let mut variances = vec![ty::Invariant; generics.count()];
// Mark all lifetimes from parent generics as unused (Bivariant).
// This will be overridden later if required.