bjoernager/rust
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Don't assume traits used as type are trait objs

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This commit is contained in:
VulnBandit 2024-10-04 16:10:28 +02:00
parent 484c8e78cb
commit 9a2772e1c2
59 changed files with 609 additions and 681 deletions
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53
compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
View file

@ -1,6 +1,6 @@
use rustc_ast::TraitObjectSyntax;
use rustc_errors::codes::*;
use rustc_errors::{Diag, EmissionGuarantee, StashKey};
use rustc_errors::{Diag, EmissionGuarantee, ErrorGuaranteed, StashKey, Suggestions};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_lint_defs::Applicability;
@ -15,13 +15,16 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
///
/// *Bare* trait object types are ones that aren't preceded by the keyword `dyn`.
/// In edition 2021 and onward we emit a hard error for them.
pub(super) fn prohibit_or_lint_bare_trait_object_ty(&self, self_ty: &hir::Ty<'_>) {
pub(super) fn prohibit_or_lint_bare_trait_object_ty(
&self,
self_ty: &hir::Ty<'_>,
) -> Option<ErrorGuaranteed> {
let tcx = self.tcx();
let hir::TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) =
self_ty.kind
else {
return;
return None;
};
let in_path = match tcx.parent_hir_node(self_ty.hir_id) {
@ -70,8 +73,8 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
}
if self_ty.span.edition().at_least_rust_2021() {
let msg = "trait objects must include the `dyn` keyword";
let label = "add `dyn` keyword before this trait";
let msg = "expected a type, found a trait";
let label = "you can add the `dyn` keyword if you want a trait object";
let mut diag =
rustc_errors::struct_span_code_err!(self.dcx(), self_ty.span, E0782, "{}", msg);
if self_ty.span.can_be_used_for_suggestions()
@ -83,7 +86,17 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
// Check if the impl trait that we are considering is an impl of a local trait.
self.maybe_suggest_blanket_trait_impl(self_ty, &mut diag);
self.maybe_suggest_assoc_ty_bound(self_ty, &mut diag);
diag.stash(self_ty.span, StashKey::TraitMissingMethod);
// In case there is an associate type with the same name
// Add the suggestion to this error
if let Some(mut sugg) =
tcx.dcx().steal_non_err(self_ty.span, StashKey::AssociatedTypeSuggestion)
&& let Suggestions::Enabled(ref mut s1) = diag.suggestions
&& let Suggestions::Enabled(ref mut s2) = sugg.suggestions
{
s1.append(s2);
sugg.cancel();
}
diag.stash(self_ty.span, StashKey::TraitMissingMethod)
} else {
tcx.node_span_lint(BARE_TRAIT_OBJECTS, self_ty.hir_id, self_ty.span, |lint| {
lint.primary_message("trait objects without an explicit `dyn` are deprecated");
@ -96,6 +109,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
}
self.maybe_suggest_blanket_trait_impl(self_ty, lint);
});
None
}
}
@ -174,41 +188,31 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
// 1. Independent functions
// 2. Functions inside trait blocks
// 3. Functions inside impl blocks
let (sig, generics, owner) = match tcx.hir_node_by_def_id(parent_id) {
let (sig, generics) = match tcx.hir_node_by_def_id(parent_id) {
hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, generics, _), .. }) => {
(sig, generics, None)
(sig, generics)
}
hir::Node::TraitItem(hir::TraitItem {
kind: hir::TraitItemKind::Fn(sig, _),
generics,
owner_id,
..
}) => (sig, generics, Some(tcx.parent(owner_id.to_def_id()))),
}) => (sig, generics),
hir::Node::ImplItem(hir::ImplItem {
kind: hir::ImplItemKind::Fn(sig, _),
generics,
owner_id,
..
}) => (sig, generics, Some(tcx.parent(owner_id.to_def_id()))),
}) => (sig, generics),
_ => return false,
};
let Ok(trait_name) = tcx.sess.source_map().span_to_snippet(self_ty.span) else {
return false;
};
let impl_sugg = vec![(self_ty.span.shrink_to_lo(), "impl ".to_string())];
let mut is_downgradable = true;
// Check if trait object is safe for suggesting dynamic dispatch.
let is_dyn_compatible = match self_ty.kind {
hir::TyKind::TraitObject(objects, ..) => {
objects.iter().all(|(o, _)| match o.trait_ref.path.res {
Res::Def(DefKind::Trait, id) => {
if Some(id) == owner {
// For recursive traits, don't downgrade the error. (#119652)
is_downgradable = false;
}
tcx.is_dyn_compatible(id)
}
Res::Def(DefKind::Trait, id) => tcx.is_dyn_compatible(id),
_ => false,
})
}
@ -255,9 +259,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
suggestion,
Applicability::MachineApplicable,
);
} else if is_downgradable {
// We'll emit the dyn-compatibility error already, with a structured suggestion.
diag.downgrade_to_delayed_bug();
}
return true;
}
@ -281,10 +282,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
);
if !is_dyn_compatible {
diag.note(format!("`{trait_name}` it is dyn-incompatible, so it can't be `dyn`"));
if is_downgradable {
// We'll emit the dyn-compatibility error already, with a structured suggestion.
diag.downgrade_to_delayed_bug();
}
} else {
// No ampersand in suggestion if it's borrowed already
let (dyn_str, paren_dyn_str) =

19
compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
View file

@ -2063,13 +2063,18 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
)
}
hir::TyKind::TraitObject(bounds, lifetime, repr) => {
self.prohibit_or_lint_bare_trait_object_ty(hir_ty);
let repr = match repr {
TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
TraitObjectSyntax::DynStar => ty::DynStar,
};
self.lower_trait_object_ty(hir_ty.span, hir_ty.hir_id, bounds, lifetime, repr)
if let Some(guar) = self.prohibit_or_lint_bare_trait_object_ty(hir_ty) {
// Don't continue with type analysis if the `dyn` keyword is missing
// It generates confusing errors, especially if the user meant to use another
// keyword like `impl`
Ty::new_error(tcx, guar)
} else {
let repr = match repr {
TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
TraitObjectSyntax::DynStar => ty::DynStar,
};
self.lower_trait_object_ty(hir_ty.span, hir_ty.hir_id, bounds, lifetime, repr)
}
}
// If we encounter a fully qualified path with RTN generics, then it must have
// *not* gone through `lower_ty_maybe_return_type_notation`, and therefore