bjoernager/rust
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Rework supertrait lint once again

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This commit is contained in:
Michael Goulet 2023-11-18 19:29:39 +00:00
parent 06d1afe518
commit 15fbcc3636
10 changed files with 125 additions and 25 deletions
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42
compiler/rustc_lint/src/deref_into_dyn_supertrait.rs
View file

@ -53,35 +53,43 @@ impl<'tcx> LateLintPass<'tcx> for DerefIntoDynSupertrait {
let tcx = cx.tcx;
// `Deref` is being implemented for `t`
if let hir::ItemKind::Impl(impl_) = item.kind
// the trait is a `Deref` implementation
&& let Some(trait_) = &impl_.of_trait
&& let t = tcx.type_of(item.owner_id).instantiate_identity()
&& let opt_did @ Some(did) = trait_.trait_def_id()
&& opt_did == tcx.lang_items().deref_trait()
// `t` is `dyn t_principal`
&& let ty::Dynamic(data, _, ty::Dyn) = t.kind()
&& let Some(t_principal) = data.principal()
&& let Some(did) = trait_.trait_def_id()
&& Some(did) == tcx.lang_items().deref_trait()
// the self type is `dyn t_principal`
&& let self_ty = tcx.type_of(item.owner_id).instantiate_identity()
&& let ty::Dynamic(data, _, ty::Dyn) = self_ty.kind()
&& let Some(self_principal) = data.principal()
// `<T as Deref>::Target` is `dyn target_principal`
&& let Some(target) = cx.get_associated_type(t, did, "Target")
&& let Some(target) = cx.get_associated_type(self_ty, did, "Target")
&& let ty::Dynamic(data, _, ty::Dyn) = target.kind()
&& let Some(target_principal) = data.principal()
// `target_principal` is a supertrait of `t_principal`
&& supertraits(tcx, t_principal.with_self_ty(tcx, tcx.types.trait_object_dummy_self))
.any(|sup| {
tcx.erase_regions(
sup.map_bound(|x| ty::ExistentialTraitRef::erase_self_ty(tcx, x)),
) == tcx.erase_regions(target_principal)
})
&& let Some(supertrait_principal) = supertraits(tcx, self_principal.with_self_ty(tcx, self_ty))
.find(|supertrait| supertrait.def_id() == target_principal.def_id())
{
let t = tcx.erase_regions(t);
let label = impl_
// erase regions in self type for better diagnostic presentation
let (self_ty, target_principal, supertrait_principal) =
tcx.erase_regions((self_ty, target_principal, supertrait_principal));
let label2 = impl_
.items
.iter()
.find_map(|i| (i.ident.name == sym::Target).then_some(i.span))
.map(|label| SupertraitAsDerefTargetLabel { label });
let span = tcx.def_span(item.owner_id.def_id);
cx.emit_spanned_lint(
DEREF_INTO_DYN_SUPERTRAIT,
tcx.def_span(item.owner_id.def_id),
SupertraitAsDerefTarget { t, label },
span,
SupertraitAsDerefTarget {
self_ty,
supertrait_principal: supertrait_principal.map_bound(|trait_ref| {
ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
}),
target_principal,
label: span,
label2,
},
);
}
}

14
compiler/rustc_lint/src/lints.rs
View file

@ -10,7 +10,9 @@ use rustc_errors::{
};
use rustc_hir::def_id::DefId;
use rustc_macros::{LintDiagnostic, Subdiagnostic};
use rustc_middle::ty::{inhabitedness::InhabitedPredicate, Clause, Ty, TyCtxt};
use rustc_middle::ty::{
inhabitedness::InhabitedPredicate, Clause, PolyExistentialTraitRef, Ty, TyCtxt,
};
use rustc_session::parse::ParseSess;
use rustc_span::{edition::Edition, sym, symbol::Ident, Span, Symbol};
@ -556,13 +558,17 @@ pub enum BuiltinSpecialModuleNameUsed {
#[diag(lint_supertrait_as_deref_target)]
#[help]
pub struct SupertraitAsDerefTarget<'a> {
pub t: Ty<'a>,
pub self_ty: Ty<'a>,
pub supertrait_principal: PolyExistentialTraitRef<'a>,
pub target_principal: PolyExistentialTraitRef<'a>,
#[label]
pub label: Span,
#[subdiagnostic]
pub label: Option<SupertraitAsDerefTargetLabel>,
pub label2: Option<SupertraitAsDerefTargetLabel>,
}
#[derive(Subdiagnostic)]
#[label(lint_label)]
#[label(lint_label2)]
pub struct SupertraitAsDerefTargetLabel {
#[primary_span]
pub label: Span,