bjoernager/rust
bjoernager/rust
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Change based on comments

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Instead of just switching to a probe, check for different matches, and see how many there are.
If one, unify it, otherwise return true and let it be unified later.
This commit is contained in:
kadmin 2022-12-13 09:51:13 +00:00
parent abe040d876
commit 77b61379b6
3 changed files with 38 additions and 8 deletions
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33
compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
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@ -168,7 +168,9 @@ fn satisfied_from_param_env<'tcx>(
param_env: ty::ParamEnv<'tcx>,
infcx: &'a InferCtxt<'tcx>,
single_match: Option<Result<ty::Const<'tcx>, ()>>,
}
impl<'a, 'tcx> TypeVisitor<'tcx> for Visitor<'a, 'tcx> {
type BreakTy = ();
fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
@ -179,7 +181,9 @@ fn satisfied_from_param_env<'tcx>(
&& ocx.eq(&ObligationCause::dummy(), self.param_env, c, self.ct).is_ok()
&& ocx.select_all_or_error().is_empty()
}) {
ControlFlow::BREAK
self.single_match =
if self.single_match.is_none() { Some(Ok(c)) } else { Some(Err(())) };
ControlFlow::CONTINUE
} else if let ty::ConstKind::Expr(e) = c.kind() {
e.visit_with(self)
} else {
@ -195,22 +199,37 @@ fn satisfied_from_param_env<'tcx>(
}
}
let mut single_match: Option<Result<ty::Const<'tcx>, ()>> = None;
for pred in param_env.caller_bounds() {
match pred.kind().skip_binder() {
ty::PredicateKind::ConstEvaluatable(ce) => {
let b_ct = tcx.expand_abstract_consts(ce);
let mut v = Visitor { ct, infcx, param_env };
let result = b_ct.visit_with(&mut v);
if let ControlFlow::Break(()) = result {
debug!("is_const_evaluatable: yes");
return true;
let mut v = Visitor { ct, infcx, param_env, single_match: None };
let _ = b_ct.visit_with(&mut v);
if let Some(inner) = v.single_match {
single_match = if single_match.is_none() { Some(inner) } else { Some(Err(())) };
}
}
_ => {} // don't care
}
}
if let Some(c) = single_match {
if let Ok(c) = c {
let is_ok = infcx
.commit_if_ok(|_| {
let ocx = ObligationCtxt::new_in_snapshot(infcx);
assert!(ocx.eq(&ObligationCause::dummy(), param_env, c.ty(), ct.ty()).is_ok());
assert!(ocx.eq(&ObligationCause::dummy(), param_env, c, ct).is_ok());
if ocx.select_all_or_error().is_empty() { Ok(()) } else { Err(()) }
})
.is_ok();
assert!(is_ok);
}
return true;
}
debug!("is_const_evaluatable: no");
false
}