bjoernager/rust
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normalize in trait_ref_is_knowable in new solver

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This commit is contained in:
lcnr 2023-08-04 12:17:28 +02:00
parent 1e836d12d3
commit 9eeaf1fd13
10 changed files with 214 additions and 83 deletions
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39
compiler/rustc_trait_selection/src/solve/trait_goals.rs
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@ -448,7 +448,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
// We need to normalize the b_ty since it's matched structurally
// in the other functions below.
let b_ty = match ecx
.normalize_non_self_ty(goal.predicate.trait_ref.args.type_at(1), goal.param_env)
.try_normalize_ty(goal.param_env, goal.predicate.trait_ref.args.type_at(1))
{
Ok(Some(b_ty)) => b_ty,
Ok(None) => return vec![misc_candidate(ecx, Certainty::OVERFLOW)],
@ -927,41 +927,4 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
let candidates = self.assemble_and_evaluate_candidates(goal);
self.merge_candidates(candidates)
}
/// Normalize a non-self type when it is structually matched on when solving
/// a built-in goal.
///
/// This is handled already through `assemble_candidates_after_normalizing_self_ty`
/// for the self type, but for other goals, additional normalization of other
/// arguments may be needed to completely implement the semantics of the trait.
///
/// This is required when structurally matching on any trait argument that is
/// not the self type.
fn normalize_non_self_ty(
&mut self,
mut ty: Ty<'tcx>,
param_env: ty::ParamEnv<'tcx>,
) -> Result<Option<Ty<'tcx>>, NoSolution> {
if !matches!(ty.kind(), ty::Alias(..)) {
return Ok(Some(ty));
}
for _ in 0..self.local_overflow_limit() {
let ty::Alias(_, projection_ty) = *ty.kind() else {
return Ok(Some(ty));
};
let normalized_ty = self.next_ty_infer();
let normalizes_to_goal = Goal::new(
self.tcx(),
param_env,
ty::ProjectionPredicate { projection_ty, term: normalized_ty.into() },
);
self.add_goal(normalizes_to_goal);
self.try_evaluate_added_goals()?;
ty = self.resolve_vars_if_possible(normalized_ty);
}
Ok(None)
}
}