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fix: Assertion failure on closure with unbound function
Previously that we asserted that callee inference always succeeded
when FnOnce is defined. This isn't true when we have a closure that
references an unbound function.
rustc itself had a similar issue in rust-lang/rust#157951.
Remove the failing assertion and add a unit test.
AI disclosure: Bisected by Opus 4.8, initial implementation by GPT
5.5.
| -rw-r--r-- | crates/hir-ty/src/infer/callee.rs | 8 | ||||
| -rw-r--r-- | crates/hir-ty/src/tests/regression.rs | 12 |
2 files changed, 13 insertions, 7 deletions
diff --git a/crates/hir-ty/src/infer/callee.rs b/crates/hir-ty/src/infer/callee.rs index a661731e60..e5304582ca 100644 --- a/crates/hir-ty/src/infer/callee.rs +++ b/crates/hir-ty/src/infer/callee.rs @@ -585,13 +585,7 @@ impl<'a, 'db> DeferredCallResolution<'db> { method_callee.args, ); } - None => { - assert!( - ctx.lang_items.FnOnce.is_none(), - "Expected to find a suitable `Fn`/`FnMut`/`FnOnce` implementation for `{:?}`", - self.closure_ty - ) - } + None => {} } } } diff --git a/crates/hir-ty/src/tests/regression.rs b/crates/hir-ty/src/tests/regression.rs index c5bf521d35..2ef8999817 100644 --- a/crates/hir-ty/src/tests/regression.rs +++ b/crates/hir-ty/src/tests/regression.rs @@ -2935,3 +2935,15 @@ impl Foo for Bar { "#, ); } + +#[test] +fn regression_unresolved_deferred_closure_call_resolution() { + check_no_mismatches( + r#" +//- minicore: fn +fn caller() { + let _: &[u8] = &(|| encode_fn())(); +} +"#, + ); +} |