Rollup merge of #104038 - compiler-errors:super-norm-closure-sig, r=lcnr

Normalize types when deducing closure signature from supertraits

Elaborated supertraits should be normalized, since there's no guarantee they don't contain projections 😅

Fixes #104025
r? types

src/test/ui/closures/supertrait-hint-references-assoc-ty.rs

@@ -0,0 +1,17 @@
+// check-pass
+
+pub trait Fn0: Fn(i32) -> Self::Out {
+    type Out;
+}
+
+impl<F: Fn(i32) -> ()> Fn0 for F {
+    type Out = ();
+}
+
+pub fn closure_typer(_: impl Fn0) {}
+
+fn main() {
+    closure_typer(move |x| {
+        let _: i64 = x.into();
+    });
+}