typeck: suggest (x.field)(...) to call struct fields even when x is a reference

Fixes: #33784

src/test/compile-fail/issue-33784.rs

@@ -0,0 +1,46 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::ops::Deref;
+
+struct Obj<F> where F: FnMut() -> u32 {
+    fn_ptr: fn() -> (),
+    closure: F,
+}
+
+struct C {
+    c_fn_ptr: fn() -> (),
+}
+
+struct D(C);
+
+impl Deref for D {
+    type Target = C;
+    fn deref(&self) -> &C {
+        &self.0
+    }
+}
+
+
+fn empty() {}
+
+fn main() {
+    let o = Obj { fn_ptr: empty, closure: || 42 };
+    let p = &o;
+    p.closure(); //~ ERROR no method named `closure` found
+    //~^ NOTE use `(p.closure)(...)` if you meant to call the function stored in the `closure` field
+    let q = &p;
+    q.fn_ptr(); //~ ERROR no method named `fn_ptr` found
+    //~^ NOTE use `(q.fn_ptr)(...)` if you meant to call the function stored in the `fn_ptr` field
+    let r = D(C { c_fn_ptr: empty });
+    let s = &r;
+    s.c_fn_ptr(); //~ ERROR no method named `c_fn_ptr` found
+    //~^ NOTE use `(s.c_fn_ptr)(...)` if you meant to call the function stored in the `c_fn_ptr`
+}