Start moving to the rustc guide!

CONTRIBUTING.md

@@ -623,6 +623,7 @@ For people new to Rust, and just starting to contribute, or even for
 more seasoned developers, some useful places to look for information
 are:
 
+* The [rustc guide] contains information about how various parts of the compiler work
 * [Rust Forge][rustforge] contains additional documentation, including write-ups of how to achieve common tasks
 * The [Rust Internals forum][rif], a place to ask questions and
   discuss Rust's internals
@@ -635,6 +636,7 @@ are:
 * **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
 * Don't be afraid to ask! The Rust community is friendly and helpful.
 
+[rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html
 [gdfrustc]: http://manishearth.github.io/rust-internals-docs/rustc/
 [gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
 [rif]: http://internals.rust-lang.org

README.md

@@ -227,9 +227,13 @@ variety of channels on Mozilla's IRC network, irc.mozilla.org. The
 most popular channel is [#rust], a venue for general discussion about
 Rust. And a good place to ask for help would be [#rust-beginners].
 
+Also, the [rustc guide] might be a good place to start if you want to
+find out how various parts of the compiler work.
+
 [IRC]: https://en.wikipedia.org/wiki/Internet_Relay_Chat
 [#rust]: irc://irc.mozilla.org/rust
 [#rust-beginners]: irc://irc.mozilla.org/rust-beginners
+[rustc-guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html
 
 ## License
 [license]: #license

src/README.md

@@ -0,0 +1,15 @@
+This directory contains the source code of the rust project, including:
+- `rustc` and its tests
+- `libstd`
+- Various submodules for tools, like rustdoc, rls, etc.
+
+For more information on how various parts of the compiler work, see the [rustc guide].
+
+Their is also useful content in the following READMEs, which are gradually being moved over to the guide:
+- https://github.com/rust-lang/rust/tree/master/src/librustc/ty/maps
+- https://github.com/rust-lang/rust/tree/master/src/librustc/dep_graph
+- https://github.com/rust-lang/rust/blob/master/src/librustc/infer/region_constraints
+- https://github.com/rust-lang/rust/tree/master/src/librustc/infer/higher_ranked
+- https://github.com/rust-lang/rust/tree/master/src/librustc/infer/lexical_region_resolve
+
+[rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html