bjoernager/rust
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drop global where-bounds before merging candidates

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This commit is contained in:
lcnr 2025-04-14 12:43:16 +02:00
parent 092a284ba0
commit 2c2c9df653
5 changed files with 93 additions and 6 deletions
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8
compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
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@ -1238,10 +1238,11 @@ where
D: SolverDelegate<Interner = I>,
I: Interner,
{
#[instrument(level = "debug", skip(self, goal), ret)]
pub(super) fn merge_trait_candidates(
&mut self,
goal: Goal<I, TraitPredicate<I>>,
candidates: Vec<Candidate<I>>,
mut candidates: Vec<Candidate<I>>,
) -> Result<(CanonicalResponse<I>, Option<TraitGoalProvenVia>), NoSolution> {
if let TypingMode::Coherence = self.typing_mode() {
let all_candidates: Vec<_> = candidates.into_iter().map(|c| c.result).collect();
@ -1323,13 +1324,16 @@ where
// If there are *only* global where bounds, then make sure to return that this
// is still reported as being proven-via the param-env so that rigid projections
// operate correctly.
// operate correctly. Otherwise, drop all global where-bounds before merging the
// remaining candidates.
let proven_via =
if candidates.iter().all(|c| matches!(c.source, CandidateSource::ParamEnv(_))) {
TraitGoalProvenVia::ParamEnv
} else {
candidates.retain(|c| !matches!(c.source, CandidateSource::ParamEnv(_)));
TraitGoalProvenVia::Misc
};
let all_candidates: Vec<_> = candidates.into_iter().map(|c| c.result).collect();
if let Some(response) = self.try_merge_responses(&all_candidates) {
Ok((response, Some(proven_via)))