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Constrain const vars to error if const types are mismatched

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This commit is contained in:
Michael Goulet 2023-03-19 02:17:44 +00:00
parent ab9bb3ea36
commit 322c7b6269
5 changed files with 39 additions and 8 deletions
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17
compiler/rustc_infer/src/infer/combine.rs
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@ -189,10 +189,19 @@ impl<'tcx> InferCtxt<'tcx> {
// the expected const's type. Specifically, we don't want const infer vars
// to do any type shapeshifting before and after resolution.
if let Err(guar) = compatible_types {
return Ok(self.tcx.const_error_with_guaranteed(
if relation.a_is_expected() { a.ty() } else { b.ty() },
guar,
));
// HACK: equating both sides with `[const error]` eagerly prevents us
// from leaving unconstrained inference vars during things like impl
// matching in the solver.
let a_error = self.tcx.const_error_with_guaranteed(a.ty(), guar);
if let ty::ConstKind::Infer(InferConst::Var(vid)) = a.kind() {
return self.unify_const_variable(vid, a_error);
}
let b_error = self.tcx.const_error_with_guaranteed(b.ty(), guar);
if let ty::ConstKind::Infer(InferConst::Var(vid)) = b.kind() {
return self.unify_const_variable(vid, b_error);
}
return Ok(if relation.a_is_expected() { a_error } else { b_error });
}
match (a.kind(), b.kind()) {