Rollup merge of #102378 - compiler-errors:issue-102289, r=jackh726

Use already resolved `self_ty` in `confirm_fn_pointer_candidate`

Fixes #102289

2 files changed, 56 insertions, 1 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 27fbfb6dd21..dd49dcecf77 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -626,7 +626,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // the signature, as evidenced by how we treat it during projection.
         // The safe thing to do here is to liberate it, though, which should
         // have no worse effect than skipping the binder here.
-        let liberated_fn_ty = self.infcx.replace_bound_vars_with_placeholders(obligation.self_ty());
+        let liberated_fn_ty =
+            self.infcx.replace_bound_vars_with_placeholders(obligation.predicate.rebind(self_ty));
         let output_ty = self
             .infcx
             .replace_bound_vars_with_placeholders(liberated_fn_ty.fn_sig(self.tcx()).output());
diff --git a/src/test/ui/function-pointer/issue-102289.rs b/src/test/ui/function-pointer/issue-102289.rs
new file mode 100644
index 00000000000..de394ca9ad6
--- /dev/null
+++ b/src/test/ui/function-pointer/issue-102289.rs
@@ -0,0 +1,54 @@
+// check-pass
+
+pub(crate) trait Parser: Sized {
+    type Output;
+    fn parse(&mut self, _input: &str) -> Result<(), ()> {
+        loop {}
+    }
+    fn map<F, B>(self, _f: F) -> Map<Self, F>
+    where
+        F: FnMut(Self::Output) -> B,
+    {
+        todo!()
+    }
+}
+
+pub(crate) struct Chainl1<P, Op>(P, Op);
+impl<P, Op> Parser for Chainl1<P, Op>
+where
+    P: Parser,
+    Op: Parser,
+    Op::Output: FnOnce(P::Output, P::Output) -> P::Output,
+{
+    type Output = P::Output;
+}
+pub(crate) fn chainl1<P, Op>(_parser: P, _op: Op) -> Chainl1<P, Op>
+where
+    P: Parser,
+    Op: Parser,
+    Op::Output: FnOnce(P::Output, P::Output) -> P::Output,
+{
+    loop {}
+}
+
+pub(crate) struct Map<P, F>(P, F);
+impl<A, B, P, F> Parser for Map<P, F>
+where
+    P: Parser<Output = A>,
+    F: FnMut(A) -> B,
+{
+    type Output = B;
+}
+
+impl Parser for u32 {
+    type Output = ();
+}
+
+pub fn chainl1_error_consume() {
+    fn first<T, U>(t: T, _: U) -> T {
+        t
+    }
+    let _ = chainl1(1, 1.map(|_| first)).parse("");
+}
+
+fn main() {}