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Rollup merge of #112965 - compiler-errors:circular-wf, r=aliemjay

Don't emit same goal as input during `wf::unnormalized_obligations`

r? `@aliemjay` cc `@lcnr`

I accidentally pruned the logic to handle `WF(?0)` when writing `wf::unnormalized_obligations`.

idk if you wanted to construct a test first, but this is an obvious fix. Copied the comment from above.

Fixes rust-lang/trait-system-refactor-initiative#36
This commit is contained in:
Michael Goulet 2023-06-23 19:47:21 -07:00 committed by GitHub
commit 766db8161b
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6 changed files with 27 additions and 5 deletions

View file

@ -1049,6 +1049,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
}
ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(ty)) => {
let ty = self.resolve_vars_if_possible(ty);
match self.tcx.sess.opts.unstable_opts.trait_solver {
TraitSolver::Classic => {
// WF predicates cannot themselves make

View file

@ -77,12 +77,19 @@ pub fn unnormalized_obligations<'tcx>(
param_env: ty::ParamEnv<'tcx>,
arg: GenericArg<'tcx>,
) -> Option<Vec<traits::PredicateObligation<'tcx>>> {
debug_assert_eq!(arg, infcx.resolve_vars_if_possible(arg));
// However, if `arg` IS an unresolved inference variable, returns `None`,
// because we are not able to make any progress at all. This is to prevent
// "livelock" where we say "$0 is WF if $0 is WF".
if arg.is_non_region_infer() {
return None;
}
if let ty::GenericArgKind::Lifetime(..) = arg.unpack() {
return Some(vec![]);
}
debug_assert_eq!(arg, infcx.resolve_vars_if_possible(arg));
let mut wf = WfPredicates {
infcx,
param_env,