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use type_implements_trait to check Param clone

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This commit is contained in:
yukang 2023-01-07 07:16:48 +08:00
parent ce4afed2ef
commit 6082729646
2 changed files with 9 additions and 22 deletions
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27
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -1121,36 +1121,23 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
let Some(generics) = self.tcx.hir().get_generics(owner.def_id) else { return false };
let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false };
let ty::Param(param) = inner_ty.kind() else { return false };
let Some(generic_param) = generics.get_named(param.name) else { return false };
let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = obligation.cause.code() else { return false };
let arg_node = self.tcx.hir().get(*arg_hir_id);
let Node::Expr(Expr { kind: hir::ExprKind::Path(_), ..}) = arg_node else { return false };
let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None);
let has_clone = self
.type_implements_trait(clone_trait, [ty], obligation.param_env)
.must_apply_modulo_regions();
let has_clone = |ty| {
self.type_implements_trait(clone_trait, [ty], obligation.param_env)
.must_apply_modulo_regions()
};
let trait_pred_and_suggested_ty =
trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty));
let new_obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
trait_pred_and_suggested_ty,
trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)),
);
if has_clone && self.predicate_may_hold(&new_obligation) {
let clone_bound = generics
.bounds_for_param(generic_param.def_id)
.flat_map(|bp| bp.bounds)
.any(|bound| {
if let hir::GenericBound::Trait(hir::PolyTraitRef { trait_ref, .. }, ..) = bound
{
Some(clone_trait) == trait_ref.trait_def_id()
} else {
false
}
});
if !clone_bound {
if self.predicate_may_hold(&new_obligation) && has_clone(ty) {
if !has_clone(param.to_ty(self.tcx)) {
suggest_constraining_type_param(
self.tcx,
generics,