bjoernager/rust
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Check nested obligations during coercion unify

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This commit is contained in:
Michael Goulet 2023-05-27 17:35:17 +00:00
parent 23040c4a5f
commit 00c92bd873
2 changed files with 20 additions and 1 deletions
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19
compiler/rustc_hir_typeck/src/coercion.rs
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@ -62,6 +62,7 @@ use rustc_span::{self, BytePos, DesugaringKind, Span};
use rustc_target::spec::abi::Abi;
use rustc_trait_selection::infer::InferCtxtExt as _;
use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
use rustc_trait_selection::traits::{
self, NormalizeExt, ObligationCause, ObligationCauseCode, ObligationCtxt,
};
@ -144,12 +145,28 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
debug!("unify(a: {:?}, b: {:?}, use_lub: {})", a, b, self.use_lub);
self.commit_if_ok(|_| {
let at = self.at(&self.cause, self.fcx.param_env);
if self.use_lub {
let res = if self.use_lub {
at.lub(DefineOpaqueTypes::Yes, b, a)
} else {
at.sup(DefineOpaqueTypes::Yes, b, a)
.map(|InferOk { value: (), obligations }| InferOk { value: a, obligations })
};
// In the new solver, lazy norm may allow us to shallowly equate
// more types, but we emit possibly impossible-to-satisfy obligations.
// Filter these cases out to make sure our coercion is more accurate.
if self.tcx.trait_solver_next() {
if let Ok(res) = &res {
for obligation in &res.obligations {
if !self.predicate_may_hold(&obligation) {
return Err(TypeError::Mismatch);
}
}
}
}
res
})
}