librustc: Forbid inherent implementations that aren't adjacent to the

type they provide an implementation for.

This breaks code like:

    mod foo {
        struct Foo { ... }
    }

    impl foo::Foo {
        ...
    }

Change this code to:

    mod foo {
        struct Foo { ... }

        impl Foo {
            ...
        }
    }

Additionally, if you used the I/O path extension methods `stat`,
`lstat`, `exists`, `is_file`, or `is_dir`, note that these methods have
been moved to the the `std::io::fs::PathExtensions` trait. This breaks
code like:

    fn is_it_there() -> bool {
        Path::new("/foo/bar/baz").exists()
    }

Change this code to:

    use std::io::fs::PathExtensions;

    fn is_it_there() -> bool {
        Path::new("/foo/bar/baz").exists()
    }

Closes #17059.

RFC #155.

[breaking-change]

src/librustdoc/html/render.rs

@@ -35,6 +35,7 @@
 
 use std::collections::{HashMap, HashSet};
 use std::fmt;
+use std::io::fs::PathExtensions;
 use std::io::{fs, File, BufferedWriter, MemWriter, BufferedReader};
 use std::io;
 use std::str;