Rollup merge of #72280 - nbdd0121:typeck, r=nikomatsakis

Fix up autoderef when reborrowing

Currently `(f)()` and `f.call_mut()` behaves differently if expression `f` contains autoderef in it. This causes a weird error in #72225.

When `f` is type checked, `Deref` is used (this is expected as we can't yet determine if we should use `Fn` or `FnMut`). When subsequently we determine the actual trait to be used, when using the `f.call_mut()` syntax the `Deref` is patched to `DerefMut`, while for the `(f)()` syntax case it is not.

This PR replicates the fixup for the first case.

Fixes #72225
Fixes #68590

src/test/ui/typeck/issue-68590-reborrow-through-derefmut.rs

@@ -0,0 +1,25 @@
+// check-pass
+
+// rust-lang/rust#68590: confusing diagnostics when reborrowing through DerefMut.
+
+use std::cell::RefCell;
+
+struct A;
+
+struct S<'a> {
+    a: &'a mut A,
+}
+
+fn take_a(_: &mut A) {}
+
+fn test<'a>(s: &RefCell<S<'a>>) {
+    let mut guard = s.borrow_mut();
+    take_a(guard.a);
+    let _s2 = S { a: guard.a };
+}
+
+fn main() {
+    let a = &mut A;
+    let s = RefCell::new(S { a });
+    test(&s);
+}

src/test/ui/typeck/issue-72225-call-fnmut-through-derefmut.rs

@@ -0,0 +1,21 @@
+// check-pass
+
+// rust-lang/rust#72225: confusing diagnostics when calling FnMut through DerefMut.
+
+use std::cell::RefCell;
+
+struct S {
+    f: Box<dyn FnMut()>
+}
+
+fn test(s: &RefCell<S>) {
+    let mut guard = s.borrow_mut();
+    (guard.f)();
+}
+
+fn main() {
+    let s = RefCell::new(S {
+        f: Box::new(|| ())
+    });
+    test(&s);
+}