Check projection arguments before substitution

This commit is contained in:
Michael Goulet 2023-08-14 20:49:08 +00:00
parent 1b198b3a19
commit 77c6c38add
4 changed files with 31 additions and 8 deletions

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@ -1,4 +1,4 @@
use crate::traits::specialization_graph;
use crate::traits::{check_args_compatible, specialization_graph};
use super::assembly::{self, structural_traits};
use super::EvalCtxt;
@ -190,11 +190,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS);
};
if !assoc_def.item.defaultness(tcx).has_value() {
let guar = tcx.sess.delay_span_bug(
tcx.def_span(assoc_def.item.def_id),
"missing value for assoc item in impl",
);
let error_response = |ecx: &mut EvalCtxt<'_, 'tcx>, reason| {
let guar = tcx.sess.delay_span_bug(tcx.def_span(assoc_def.item.def_id), reason);
let error_term = match assoc_def.item.kind {
ty::AssocKind::Const => ty::Const::new_error(
tcx,
@ -208,7 +205,11 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
};
ecx.eq(goal.param_env, goal.predicate.term, error_term)
.expect("expected goal term to be fully unconstrained");
return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes);
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
};
if !assoc_def.item.defaultness(tcx).has_value() {
return error_response(ecx, "missing value for assoc item in impl");
}
// Getting the right args here is complex, e.g. given:
@ -233,6 +234,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
assoc_def.defining_node,
);
if !check_args_compatible(tcx, assoc_def.item, args) {
return error_response(
ecx,
"associated item has mismatched generic item arguments",
);
}
// Finally we construct the actual value of the associated type.
let term = match assoc_def.item.kind {
ty::AssocKind::Type => tcx.type_of(assoc_def.item.def_id).map_bound(|ty| ty.into()),

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@ -1,5 +1,5 @@
error[E0049]: type `B` has 1 type parameter but its trait declaration has 0 type parameters
--> $DIR/issue-102114.rs:11:12
--> $DIR/issue-102114.rs:14:12
|
LL | type B<'b>;
| -- expected 0 type parameters

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@ -0,0 +1,12 @@
error[E0049]: type `B` has 1 type parameter but its trait declaration has 0 type parameters
--> $DIR/issue-102114.rs:14:12
|
LL | type B<'b>;
| -- expected 0 type parameters
...
LL | type B<T> = Wrapper<T>;
| ^ found 1 type parameter
error: aborting due to previous error
For more information about this error, try `rustc --explain E0049`.

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@ -1,3 +1,6 @@
// revisions: current next
//[next] compile-flags: -Ztrait-solver=next
trait A {
type B<'b>;
fn a() -> Self::B<'static>;