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Rollup merge of #107489 - compiler-errors:non_lifetime_binders, r=cjgillot

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Implement partial support for non-lifetime binders

This implements support for non-lifetime binders. It's pretty useless currently, but I wanted to put this up so the implementation can be discussed.

Specifically, this piggybacks off of the late-bound lifetime collection code in `rustc_hir_typeck::collect::lifetimes`. This seems like a necessary step given the fact we don't resolve late-bound regions until this point, and binders are sometimes merged.

Q: I'm not sure if I should go along this route, or try to modify the earlier nameres code to compute the right bound var indices for type and const binders eagerly... If so, I'll need to rename all these queries to something more appropriate (I've done this for `resolve_lifetime::Region` -> `resolve_lifetime::ResolvedArg`)

cc rust-lang/types-team#81

r? `@ghost`
This commit is contained in:
Matthias Krüger
2023-02-17 00:19:34 +01:00
committed by GitHub
parent 6379c727ac 95f35fe443
commit 089e8c03bc
48 changed files with 709 additions and 343 deletions
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91
compiler/rustc_hir_analysis/src/astconv/mod.rs
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@@ -14,7 +14,7 @@ use crate::errors::{
AmbiguousLifetimeBound, MultipleRelaxedDefaultBounds, TraitObjectDeclaredWithNoTraits,
TypeofReservedKeywordUsed, ValueOfAssociatedStructAlreadySpecified,
};
use crate::middle::resolve_lifetime as rl;
use crate::middle::resolve_bound_vars as rbv;
use crate::require_c_abi_if_c_variadic;
use rustc_ast::TraitObjectSyntax;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -225,10 +225,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
let tcx = self.tcx();
let lifetime_name = |def_id| tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id));
match tcx.named_region(lifetime.hir_id) {
Some(rl::Region::Static) => tcx.lifetimes.re_static,
match tcx.named_bound_var(lifetime.hir_id) {
Some(rbv::ResolvedArg::StaticLifetime) => tcx.lifetimes.re_static,
Some(rl::Region::LateBound(debruijn, index, def_id)) => {
Some(rbv::ResolvedArg::LateBound(debruijn, index, def_id)) => {
let name = lifetime_name(def_id.expect_local());
let br = ty::BoundRegion {
var: ty::BoundVar::from_u32(index),
@@ -237,7 +237,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
tcx.mk_re_late_bound(debruijn, br)
}
Some(rl::Region::EarlyBound(def_id)) => {
Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
let name = tcx.hir().ty_param_name(def_id.expect_local());
let item_def_id = tcx.hir().ty_param_owner(def_id.expect_local());
let generics = tcx.generics_of(item_def_id);
@@ -245,7 +245,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
tcx.mk_re_early_bound(ty::EarlyBoundRegion { def_id, index, name })
}
Some(rl::Region::Free(scope, id)) => {
Some(rbv::ResolvedArg::Free(scope, id)) => {
let name = lifetime_name(id.expect_local());
tcx.mk_re_free(scope, ty::BrNamed(id, name))
@@ -1607,7 +1607,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
self.ast_region_to_region(lifetime, None)
} else {
self.compute_object_lifetime_bound(span, existential_predicates).unwrap_or_else(|| {
if tcx.named_region(lifetime.hir_id).is_some() {
if tcx.named_bound_var(lifetime.hir_id).is_some() {
self.ast_region_to_region(lifetime, None)
} else {
self.re_infer(None, span).unwrap_or_else(|| {
@@ -2600,6 +2600,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
&self,
opt_self_ty: Option<Ty<'tcx>>,
path: &hir::Path<'_>,
hir_id: hir::HirId,
permit_variants: bool,
) -> Ty<'tcx> {
let tcx = self.tcx();
@@ -2663,11 +2664,25 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
});
let def_id = def_id.expect_local();
let item_def_id = tcx.hir().ty_param_owner(def_id);
let generics = tcx.generics_of(item_def_id);
let index = generics.param_def_id_to_index[&def_id.to_def_id()];
tcx.mk_ty_param(index, tcx.hir().ty_param_name(def_id))
match tcx.named_bound_var(hir_id) {
Some(rbv::ResolvedArg::LateBound(debruijn, index, _)) => {
let name =
tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id.expect_local()));
let br = ty::BoundTy {
var: ty::BoundVar::from_u32(index),
kind: ty::BoundTyKind::Param(def_id, name),
};
tcx.mk_ty(ty::Bound(debruijn, br))
}
Some(rbv::ResolvedArg::EarlyBound(_)) => {
let def_id = def_id.expect_local();
let item_def_id = tcx.hir().ty_param_owner(def_id);
let generics = tcx.generics_of(item_def_id);
let index = generics.param_def_id_to_index[&def_id.to_def_id()];
tcx.mk_ty_param(index, tcx.hir().ty_param_name(def_id))
}
arg => bug!("unexpected bound var resolution for {hir_id:?}: {arg:?}"),
}
}
Res::SelfTyParam { .. } => {
// `Self` in trait or type alias.
@@ -2870,14 +2885,22 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
hir::TyKind::BareFn(bf) => {
require_c_abi_if_c_variadic(tcx, bf.decl, bf.abi, ast_ty.span);
tcx.mk_fn_ptr(self.ty_of_fn(
let fn_ptr_ty = tcx.mk_fn_ptr(self.ty_of_fn(
ast_ty.hir_id,
bf.unsafety,
bf.abi,
bf.decl,
None,
Some(ast_ty),
))
));
if let Some(guar) =
deny_non_region_late_bound(tcx, bf.generic_params, "function pointer")
{
tcx.ty_error_with_guaranteed(guar)
} else {
fn_ptr_ty
}
}
hir::TyKind::TraitObject(bounds, lifetime, repr) => {
self.maybe_lint_bare_trait(ast_ty, in_path);
@@ -2885,12 +2908,27 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
TraitObjectSyntax::DynStar => ty::DynStar,
};
self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed, repr)
let object_ty = self.conv_object_ty_poly_trait_ref(
ast_ty.span,
bounds,
lifetime,
borrowed,
repr,
);
if let Some(guar) = bounds.iter().find_map(|trait_ref| {
deny_non_region_late_bound(tcx, trait_ref.bound_generic_params, "trait object")
}) {
tcx.ty_error_with_guaranteed(guar)
} else {
object_ty
}
}
hir::TyKind::Path(hir::QPath::Resolved(maybe_qself, path)) => {
debug!(?maybe_qself, ?path);
let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself));
self.res_to_ty(opt_self_ty, path, false)
self.res_to_ty(opt_self_ty, path, ast_ty.hir_id, false)
}
&hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => {
let opaque_ty = tcx.hir().item(item_id);
@@ -3346,3 +3384,24 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
}
}
fn deny_non_region_late_bound(
tcx: TyCtxt<'_>,
params: &[hir::GenericParam<'_>],
where_: &str,
) -> Option<ErrorGuaranteed> {
params.iter().find_map(|bad_param| {
let what = match bad_param.kind {
hir::GenericParamKind::Type { .. } => "type",
hir::GenericParamKind::Const { .. } => "const",
hir::GenericParamKind::Lifetime { .. } => return None,
};
let mut diag = tcx.sess.struct_span_err(
bad_param.span,
format!("late-bound {what} parameter not allowed on {where_} types"),
);
Some(if tcx.features().non_lifetime_binders { diag.emit() } else { diag.delay_as_bug() })
})
}