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Correctly deny late-bound lifetimes from parent in anon consts and TAITs

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This commit is contained in:
Michael Goulet 2023-09-02 21:29:27 +00:00
parent ab45885dec
commit 52aff53812
18 changed files with 230 additions and 150 deletions
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71
compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
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@ -158,13 +158,14 @@ enum Scope<'a> {
s: ScopeRef<'a>,
},
/// Disallows capturing non-lifetime binders from parent scopes.
/// Disallows capturing late-bound vars from parent scopes.
///
/// This is necessary for something like `for<T> [(); { /* references T */ }]:`,
/// since we don't do something more correct like replacing any captured
/// late-bound vars with early-bound params in the const's own generics.
AnonConstBoundary {
LateBoundary {
s: ScopeRef<'a>,
what: &'static str,
},
Root {
@ -216,7 +217,9 @@ impl<'a> fmt::Debug for TruncatedScopeDebug<'a> {
.field("s", &"..")
.finish(),
Scope::TraitRefBoundary { s: _ } => f.debug_struct("TraitRefBoundary").finish(),
Scope::AnonConstBoundary { s: _ } => f.debug_struct("AnonConstBoundary").finish(),
Scope::LateBoundary { s: _, what } => {
f.debug_struct("LateBoundary").field("what", what).finish()
}
Scope::Root { opt_parent_item } => {
f.debug_struct("Root").field("opt_parent_item", &opt_parent_item).finish()
}
@ -318,7 +321,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
break (vec![], BinderScopeType::Normal);
}
Scope::ObjectLifetimeDefault { s, .. } | Scope::AnonConstBoundary { s } => {
Scope::ObjectLifetimeDefault { s, .. } | Scope::LateBoundary { s, .. } => {
scope = s;
}
@ -697,9 +700,12 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
}) => {
intravisit::walk_ty(self, ty);
// Elided lifetimes are not allowed in non-return
// position impl Trait
let scope = Scope::TraitRefBoundary { s: self.scope };
// Elided lifetimes and late-bound lifetimes (from the parent)
// are not allowed in non-return position impl Trait
let scope = Scope::LateBoundary {
s: &Scope::TraitRefBoundary { s: self.scope },
what: "type alias impl trait",
};
self.with(scope, |this| intravisit::walk_item(this, opaque_ty));
return;
@ -979,7 +985,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
}
fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
self.with(Scope::AnonConstBoundary { s: self.scope }, |this| {
self.with(Scope::LateBoundary { s: self.scope, what: "constant" }, |this| {
intravisit::walk_anon_const(this, c);
});
}
@ -1174,6 +1180,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
let mut late_depth = 0;
let mut scope = self.scope;
let mut outermost_body = None;
let mut crossed_late_boundary = None;
let result = loop {
match *scope {
Scope::Body { id, s } => {
@ -1258,8 +1265,12 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. }
| Scope::AnonConstBoundary { s } => {
| Scope::TraitRefBoundary { s, .. } => {
scope = s;
}
Scope::LateBoundary { s, what } => {
crossed_late_boundary = Some(what);
scope = s;
}
}
@ -1268,6 +1279,22 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
if let Some(mut def) = result {
if let ResolvedArg::EarlyBound(..) = def {
// Do not free early-bound regions, only late-bound ones.
} else if let ResolvedArg::LateBound(_, _, param_def_id) = def
&& let Some(what) = crossed_late_boundary
{
let use_span = lifetime_ref.ident.span;
let def_span = self.tcx.def_span(param_def_id);
let guar = match self.tcx.def_kind(param_def_id) {
DefKind::LifetimeParam => {
self.tcx.sess.emit_err(errors::CannotCaptureLateBound::Lifetime {
use_span,
def_span,
what,
})
}
_ => unreachable!(),
};
def = ResolvedArg::Error(guar);
} else if let Some(body_id) = outermost_body {
let fn_id = self.tcx.hir().body_owner(body_id);
match self.tcx.hir().get(fn_id) {
@ -1322,7 +1349,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
| Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. }
| Scope::AnonConstBoundary { s } => {
| Scope::LateBoundary { s, .. } => {
scope = s;
}
}
@ -1341,7 +1368,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
// search.
let mut late_depth = 0;
let mut scope = self.scope;
let mut crossed_anon_const = false;
let mut crossed_late_boundary = None;
let result = loop {
match *scope {
@ -1376,28 +1403,32 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
scope = s;
}
Scope::AnonConstBoundary { s } => {
crossed_anon_const = true;
Scope::LateBoundary { s, what } => {
crossed_late_boundary = Some(what);
scope = s;
}
}
};
if let Some(def) = result {
if let ResolvedArg::LateBound(..) = def && crossed_anon_const {
if let ResolvedArg::LateBound(..) = def
&& let Some(what) = crossed_late_boundary
{
let use_span = self.tcx.hir().span(hir_id);
let def_span = self.tcx.def_span(param_def_id);
let guar = match self.tcx.def_kind(param_def_id) {
DefKind::ConstParam => {
self.tcx.sess.emit_err(errors::CannotCaptureLateBoundInAnonConst::Const {
self.tcx.sess.emit_err(errors::CannotCaptureLateBound::Const {
use_span,
def_span,
what,
})
}
DefKind::TyParam => {
self.tcx.sess.emit_err(errors::CannotCaptureLateBoundInAnonConst::Type {
self.tcx.sess.emit_err(errors::CannotCaptureLateBound::Type {
use_span,
def_span,
what,
})
}
_ => unreachable!(),
@ -1446,7 +1477,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
| Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. }
| Scope::AnonConstBoundary { s } => {
| Scope::LateBoundary { s, .. } => {
scope = s;
}
}
@ -1526,7 +1557,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
| Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. }
| Scope::AnonConstBoundary { s } => {
| Scope::LateBoundary { s, .. } => {
scope = s;
}
}
@ -1831,7 +1862,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. }
| Scope::AnonConstBoundary { s } => {
| Scope::LateBoundary { s, .. } => {
scope = s;
}
}