diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs index 7325bce6055..41295f2b7b6 100644 --- a/compiler/rustc_ast_lowering/src/item.rs +++ b/compiler/rustc_ast_lowering/src/item.rs @@ -1339,13 +1339,19 @@ impl<'hir> LoweringContext<'_, 'hir> { .map(|predicate| self.lower_where_predicate(predicate)), ); - let mut params: SmallVec<[hir::GenericParam<'hir>; 4]> = - self.lower_generic_params_mut(&generics.params).collect(); + let mut params: SmallVec<[hir::GenericParam<'hir>; 4]> = self + .lower_generic_params_mut(&generics.params, hir::GenericParamSource::Generics) + .collect(); // Introduce extra lifetimes if late resolution tells us to. let extra_lifetimes = self.resolver.take_extra_lifetime_params(parent_node_id); params.extend(extra_lifetimes.into_iter().filter_map(|(ident, node_id, res)| { - self.lifetime_res_to_generic_param(ident, node_id, res) + self.lifetime_res_to_generic_param( + ident, + node_id, + res, + hir::GenericParamSource::Generics, + ) })); let has_where_clause_predicates = !generics.where_clause.predicates.is_empty(); @@ -1449,7 +1455,8 @@ impl<'hir> LoweringContext<'_, 'hir> { span, }) => hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate { hir_id: self.next_id(), - bound_generic_params: self.lower_generic_params(bound_generic_params), + bound_generic_params: self + .lower_generic_params(bound_generic_params, hir::GenericParamSource::Binder), bounded_ty: self .lower_ty(bounded_ty, &ImplTraitContext::Disallowed(ImplTraitPosition::Bound)), bounds: self.arena.alloc_from_iter(bounds.iter().map(|bound| { diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 5d78d914b6d..5352a56b165 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -804,6 +804,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { ident: Ident, node_id: NodeId, res: LifetimeRes, + source: hir::GenericParamSource, ) -> Option> { let (name, kind) = match res { LifetimeRes::Param { .. } => { @@ -837,6 +838,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { pure_wrt_drop: false, kind: hir::GenericParamKind::Lifetime { kind }, colon_span: None, + source, }) } @@ -852,11 +854,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { binder: NodeId, generic_params: &[GenericParam], ) -> &'hir [hir::GenericParam<'hir>] { - let mut generic_params: Vec<_> = self.lower_generic_params_mut(generic_params).collect(); + let mut generic_params: Vec<_> = self + .lower_generic_params_mut(generic_params, hir::GenericParamSource::Binder) + .collect(); let extra_lifetimes = self.resolver.take_extra_lifetime_params(binder); debug!(?extra_lifetimes); generic_params.extend(extra_lifetimes.into_iter().filter_map(|(ident, node_id, res)| { - self.lifetime_res_to_generic_param(ident, node_id, res) + self.lifetime_res_to_generic_param(ident, node_id, res, hir::GenericParamSource::Binder) })); let generic_params = self.arena.alloc_from_iter(generic_params); debug!(?generic_params); @@ -1375,8 +1379,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { span, ); let ident = Ident::from_str_and_span(&pprust::ty_to_string(t), span); - let (param, bounds, path) = - self.lower_generic_and_bounds(*def_node_id, span, ident, bounds); + let (param, bounds, path) = self.lower_universal_param_and_bounds( + *def_node_id, + span, + ident, + bounds, + ); self.impl_trait_defs.push(param); if let Some(bounds) = bounds { self.impl_trait_bounds.push(bounds); @@ -1530,6 +1538,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { pure_wrt_drop: false, kind: hir::GenericParamKind::Lifetime { kind }, colon_span: None, + source: hir::GenericParamSource::Generics, } }, )); @@ -1987,6 +1996,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { pure_wrt_drop: false, kind: hir::GenericParamKind::Lifetime { kind }, colon_span: None, + source: hir::GenericParamSource::Generics, } }, )); @@ -2152,16 +2162,25 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn lower_generic_params_mut<'s>( &'s mut self, params: &'s [GenericParam], + source: hir::GenericParamSource, ) -> impl Iterator> + Captures<'a> + Captures<'s> { - params.iter().map(move |param| self.lower_generic_param(param)) + params.iter().map(move |param| self.lower_generic_param(param, source)) } - fn lower_generic_params(&mut self, params: &[GenericParam]) -> &'hir [hir::GenericParam<'hir>] { - self.arena.alloc_from_iter(self.lower_generic_params_mut(params)) + fn lower_generic_params( + &mut self, + params: &[GenericParam], + source: hir::GenericParamSource, + ) -> &'hir [hir::GenericParam<'hir>] { + self.arena.alloc_from_iter(self.lower_generic_params_mut(params, source)) } #[instrument(level = "trace", skip(self))] - fn lower_generic_param(&mut self, param: &GenericParam) -> hir::GenericParam<'hir> { + fn lower_generic_param( + &mut self, + param: &GenericParam, + source: hir::GenericParamSource, + ) -> hir::GenericParam<'hir> { let (name, kind) = self.lower_generic_param_kind(param); let hir_id = self.lower_node_id(param.id); @@ -2174,6 +2193,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { pure_wrt_drop: self.tcx.sess.contains_name(¶m.attrs, sym::may_dangle), kind, colon_span: param.colon_span.map(|s| self.lower_span(s)), + source, } } @@ -2266,7 +2286,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { } #[instrument(level = "debug", skip(self), ret)] - fn lower_generic_and_bounds( + fn lower_universal_param_and_bounds( &mut self, node_id: NodeId, span: Span, @@ -2286,6 +2306,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { span, kind: hir::GenericParamKind::Type { default: None, synthetic: true }, colon_span: None, + source: hir::GenericParamSource::Generics, }; let preds = self.lower_generic_bound_predicate( diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs index 72e9f7c1343..19d3d41c984 100644 --- a/compiler/rustc_hir/src/hir.rs +++ b/compiler/rustc_hir/src/hir.rs @@ -498,6 +498,7 @@ pub struct GenericParam<'hir> { pub pure_wrt_drop: bool, pub kind: GenericParamKind<'hir>, pub colon_span: Option, + pub source: GenericParamSource, } impl<'hir> GenericParam<'hir> { @@ -516,6 +517,20 @@ impl<'hir> GenericParam<'hir> { } } +/// Records where the generic parameter originated from. +/// +/// This can either be from an item's generics, in which case it's typically +/// early-bound (but can be a late-bound lifetime in functions, for example), +/// or from a `for<...>` binder, in which case it's late-bound (and notably, +/// does not show up in the parent item's generics). +#[derive(Debug, HashStable_Generic, PartialEq, Eq, Copy, Clone)] +pub enum GenericParamSource { + // Early or late-bound parameters defined on an item + Generics, + // Late-bound parameters defined via a `for<...>` + Binder, +} + #[derive(Default)] pub struct GenericParamCount { pub lifetimes: usize, diff --git a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs index 6c00b8ff7bd..b14e65183aa 100644 --- a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs +++ b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs @@ -1034,45 +1034,53 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> { fn object_lifetime_default(tcx: TyCtxt<'_>, param_def_id: DefId) -> ObjectLifetimeDefault { debug_assert_eq!(tcx.def_kind(param_def_id), DefKind::TyParam); let param_def_id = param_def_id.expect_local(); - let parent_def_id = tcx.local_parent(param_def_id); - let generics = tcx.hir().get_generics(parent_def_id).unwrap(); - let param_hir_id = tcx.local_def_id_to_hir_id(param_def_id); - let param = generics.params.iter().find(|p| p.hir_id == param_hir_id).unwrap(); + let hir::Node::GenericParam(param) = tcx.hir().get_by_def_id(param_def_id) else { + bug!("expected GenericParam for object_lifetime_default"); + }; + match param.source { + hir::GenericParamSource::Generics => { + let parent_def_id = tcx.local_parent(param_def_id); + let generics = tcx.hir().get_generics(parent_def_id).unwrap(); + let param_hir_id = tcx.local_def_id_to_hir_id(param_def_id); + let param = generics.params.iter().find(|p| p.hir_id == param_hir_id).unwrap(); - // Scan the bounds and where-clauses on parameters to extract bounds - // of the form `T:'a` so as to determine the `ObjectLifetimeDefault` - // for each type parameter. - match param.kind { - GenericParamKind::Type { .. } => { - let mut set = Set1::Empty; + // Scan the bounds and where-clauses on parameters to extract bounds + // of the form `T:'a` so as to determine the `ObjectLifetimeDefault` + // for each type parameter. + match param.kind { + GenericParamKind::Type { .. } => { + let mut set = Set1::Empty; - // Look for `type: ...` where clauses. - for bound in generics.bounds_for_param(param_def_id) { - // Ignore `for<'a> type: ...` as they can change what - // lifetimes mean (although we could "just" handle it). - if !bound.bound_generic_params.is_empty() { - continue; - } + // Look for `type: ...` where clauses. + for bound in generics.bounds_for_param(param_def_id) { + // Ignore `for<'a> type: ...` as they can change what + // lifetimes mean (although we could "just" handle it). + if !bound.bound_generic_params.is_empty() { + continue; + } - for bound in bound.bounds { - if let hir::GenericBound::Outlives(lifetime) = bound { - set.insert(lifetime.res); + for bound in bound.bounds { + if let hir::GenericBound::Outlives(lifetime) = bound { + set.insert(lifetime.res); + } + } + } + + match set { + Set1::Empty => ObjectLifetimeDefault::Empty, + Set1::One(hir::LifetimeName::Static) => ObjectLifetimeDefault::Static, + Set1::One(hir::LifetimeName::Param(param_def_id)) => { + ObjectLifetimeDefault::Param(param_def_id.to_def_id()) + } + _ => ObjectLifetimeDefault::Ambiguous, } } - } - - match set { - Set1::Empty => ObjectLifetimeDefault::Empty, - Set1::One(hir::LifetimeName::Static) => ObjectLifetimeDefault::Static, - Set1::One(hir::LifetimeName::Param(param_def_id)) => { - ObjectLifetimeDefault::Param(param_def_id.to_def_id()) + _ => { + bug!("object_lifetime_default_raw must only be called on a type parameter") } - _ => ObjectLifetimeDefault::Ambiguous, } } - _ => { - bug!("object_lifetime_default_raw must only be called on a type parameter") - } + hir::GenericParamSource::Binder => ObjectLifetimeDefault::Empty, } } @@ -1392,9 +1400,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { return; } - self.tcx - .sess - .delay_span_bug(self.tcx.hir().span(hir_id), "could not resolve {param_def_id:?}"); + self.tcx.sess.delay_span_bug( + self.tcx.hir().span(hir_id), + format!("could not resolve {param_def_id:?}"), + ); } #[instrument(level = "debug", skip(self))] diff --git a/tests/ui/traits/non_lifetime_binders/object-lifetime-default-for-late.rs b/tests/ui/traits/non_lifetime_binders/object-lifetime-default-for-late.rs new file mode 100644 index 00000000000..9830241c377 --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/object-lifetime-default-for-late.rs @@ -0,0 +1,7 @@ +// check-pass +// compile-flags: --crate-type=lib + +#![feature(non_lifetime_binders)] +//~^ WARN the feature `non_lifetime_binders` is incomplete + +pub fn f() where for (T, U): Copy {} diff --git a/tests/ui/traits/non_lifetime_binders/object-lifetime-default-for-late.stderr b/tests/ui/traits/non_lifetime_binders/object-lifetime-default-for-late.stderr new file mode 100644 index 00000000000..667575b72d4 --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/object-lifetime-default-for-late.stderr @@ -0,0 +1,11 @@ +warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/object-lifetime-default-for-late.rs:4:12 + | +LL | #![feature(non_lifetime_binders)] + | ^^^^^^^^^^^^^^^^^^^^ + | + = note: see issue #108185 for more information + = note: `#[warn(incomplete_features)]` on by default + +warning: 1 warning emitted +