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Auto merge of #109413 - compiler-errors:pointer-like-abi, r=cjgillot

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Enforce that `PointerLike` requires a pointer-like ABI

At least temporarily, let's ban coercing things that are pointer-sized and pointer-aligned but *not* `Abi::Scalar(..)` into `dyn*`. See: https://github.com/rust-lang/rust/pull/104694#discussion_r1142522073

This can be lifted in the future if we decie that we *want* to be able to coerce something `repr(C)` into a `dyn*`, but we'll have to figure out what to do with Miri and codegen...

r? compiler
This commit is contained in:
bors 2023-04-09 02:41:58 +00:00
commit 0030465bcc
14 changed files with 41 additions and 25 deletions
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3
compiler/rustc_trait_selection/src/solve/trait_goals.rs
View file

@ -221,8 +221,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
let self_ty = tcx.erase_regions(goal.predicate.self_ty());
if let Ok(layout) = tcx.layout_of(goal.param_env.and(self_ty))
&& layout.layout.size() == tcx.data_layout.pointer_size
&& layout.layout.align().abi == tcx.data_layout.pointer_align.abi
&& layout.layout.is_pointer_like(&tcx.data_layout)
{
// FIXME: We could make this faster by making a no-constraints response
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)

15
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View file

@ -97,7 +97,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
} else if lang_items.tuple_trait() == Some(def_id) {
self.assemble_candidate_for_tuple(obligation, &mut candidates);
} else if lang_items.pointer_like() == Some(def_id) {
self.assemble_candidate_for_ptr_sized(obligation, &mut candidates);
self.assemble_candidate_for_pointer_like(obligation, &mut candidates);
} else if lang_items.fn_ptr_trait() == Some(def_id) {
self.assemble_candidates_for_fn_ptr_trait(obligation, &mut candidates);
} else {
@ -942,15 +942,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
fn assemble_candidate_for_ptr_sized(
fn assemble_candidate_for_pointer_like(
&mut self,
obligation: &TraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
// The regions of a type don't affect the size of the type
let self_ty = self
.tcx()
.erase_regions(self.tcx().erase_late_bound_regions(obligation.predicate.self_ty()));
let tcx = self.tcx();
let self_ty =
tcx.erase_regions(tcx.erase_late_bound_regions(obligation.predicate.self_ty()));
// But if there are inference variables, we have to wait until it's resolved.
if self_ty.has_non_region_infer() {
@ -958,9 +958,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
return;
}
if let Ok(layout) = self.tcx().layout_of(obligation.param_env.and(self_ty))
&& layout.layout.size() == self.tcx().data_layout.pointer_size
&& layout.layout.align().abi == self.tcx().data_layout.pointer_align.abi
if let Ok(layout) = tcx.layout_of(obligation.param_env.and(self_ty))
&& layout.layout.is_pointer_like(&tcx.data_layout)
{
candidates.vec.push(BuiltinCandidate { has_nested: false });
}