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Rollup merge of #113395 - compiler-errors:new-solver-dyn-star-selection, r=oli-obk

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Dont ICE for `dyn* Trait: Trait` (built-in object) goals during selection in new trait solver

We were ICEing too eagerly during selection for `dyn*` goals -- both for dyn unsizing candidates and for built-in object candidates. The former should only be performed on `dyn` objects, but the latter are totally fine.
This commit is contained in:
Matthias Krüger 2023-07-06 12:12:12 +02:00 committed by GitHub
commit 72e0e177d5
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2 changed files with 9 additions and 5 deletions
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10
compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
View File

@ -213,15 +213,16 @@ fn rematch_object<'tcx>(
mut nested: Vec<PredicateObligation<'tcx>>,
) -> SelectionResult<'tcx, Selection<'tcx>> {
let self_ty = goal.predicate.self_ty();
let source_trait_ref = if let ty::Dynamic(data, _, ty::Dyn) = self_ty.kind() {
data.principal().unwrap().with_self_ty(infcx.tcx, self_ty)
} else {
let ty::Dynamic(data, _, source_kind) = *self_ty.kind()
else {
bug!()
};
let source_trait_ref = data.principal().unwrap().with_self_ty(infcx.tcx, self_ty);
let (is_upcasting, target_trait_ref_unnormalized) = if Some(goal.predicate.def_id())
== infcx.tcx.lang_items().unsize_trait()
{
assert_eq!(source_kind, ty::Dyn, "cannot upcast dyn*");
if let ty::Dynamic(data, _, ty::Dyn) = goal.predicate.trait_ref.substs.type_at(1).kind() {
(true, data.principal().unwrap().with_self_ty(infcx.tcx, self_ty))
} else {
@ -288,7 +289,8 @@ fn rematch_object<'tcx>(
bug!();
};
// If we're upcasting, get the offset of the vtable pointer, which is
// If we're upcasting, get the offset of the vtable pointer, otherwise get
// the base of the vtable.
Ok(Some(if is_upcasting {
ImplSource::TraitUpcasting(ImplSourceTraitUpcastingData { vtable_vptr_slot, nested })
} else {

4
tests/ui/dyn-star/box.rs
View File

@ -1,5 +1,7 @@
// run-pass
// compile-flags: -C opt-level=0
// revisions: current next
//[current] compile-flags: -C opt-level=0
//[next] compile-flags: -Ztrait-solver=next -C opt-level=0
#![feature(dyn_star)]
#![allow(incomplete_features)]