Forbid privacy in inner functions

Closes #10111

src/test/compile-fail/unnecessary-private.rs

@@ -0,0 +1,26 @@
+// Copyright 2013 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.
+
+fn main() {
+    pub struct A; //~ ERROR: visibility has no effect
+    pub enum B {} //~ ERROR: visibility has no effect
+    pub trait C { //~ ERROR: visibility has no effect
+        pub fn foo() {} //~ ERROR: visibility has no effect
+    }
+    impl A {
+        pub fn foo() {} //~ ERROR: visibility has no effect
+    }
+
+    struct D {
+        priv foo: int, //~ ERROR: visibility has no effect
+    }
+    pub fn foo() {} //~ ERROR: visibility has no effect
+    pub mod bar {} //~ ERROR: visibility has no effect
+}

src/test/run-pass/nested-class.rs

@@ -14,7 +14,7 @@ pub fn main() {
     }
 
     impl b {
-        pub fn do_stuff(&self) -> int { return 37; }
+        fn do_stuff(&self) -> int { return 37; }
     }
 
     fn b(i:int) -> b {