Auto merge of #134907 - Kobzol:rustc-dev-guide-josh, r=ehuss

Turn rustc-dev-guide into a Josh subtree

Discussed on [Zulip](https://rust-lang.zulipchat.com/#narrow/channel/196385-t-compiler.2Fwg-rustc-dev-guide/topic/a.20move.20to.20main.20repo.20.28rust-lang.2Frust.29).

Accompanying rustc-dev-guide PR: https://github.com/rust-lang/rustc-dev-guide/pull/2183

I didn't create a bootstrap step for rustc-dev-guide yet, because the rustc-dev-guide version that we currently use in this repo doesn't have linkcheck enabled and that fails tests.

The subtree starts with commit [ad93c5f1c49f2aeb45f7a4954017b1e607df9f5e](https://github.com/rust-lang/rustc-dev-guide/commit/ad93c5f1c49f2aeb45f7a4954017b1e607df9f5e).

What I did:
```
export DIR=src/doc/rustc-dev-guide

# Remove submodule
git submodule status ${DIR}
git submodule deinit ${DIR}
git rm -r --cached ${DIR}
rm -rf ${DIR}
# Remove rustc-dev-guide from .gitmodules
git commit -m"Removed `${DIR}` submodule"

# Import history with josh
git fetch https://github.com/rust-lang/rustc-dev-guide ad93c5f1c49f2aeb45f7a4954017b1e607df9f5e
josh-filter ':prefix=src/doc/rustc-dev-guide' FETCH_HEAD
git merge --allow-unrelated FILTERED_HEAD

# A few follow-up cleanup commits
```

r? ehuss

1 files changed, 81 insertions, 0 deletions

diff --git a/src/doc/rustc-dev-guide/examples/rustc-interface-example.rs b/src/doc/rustc-dev-guide/examples/rustc-interface-example.rs
new file mode 100644
index 00000000000..30f48ea5297
--- /dev/null
+++ b/src/doc/rustc-dev-guide/examples/rustc-interface-example.rs
@@ -0,0 +1,81 @@
+#![feature(rustc_private)]
+
+extern crate rustc_driver;
+extern crate rustc_error_codes;
+extern crate rustc_errors;
+extern crate rustc_hash;
+extern crate rustc_hir;
+extern crate rustc_interface;
+extern crate rustc_session;
+extern crate rustc_span;
+
+use std::sync::Arc;
+
+use rustc_errors::registry;
+use rustc_hash::FxHashMap;
+use rustc_session::config;
+
+fn main() {
+    let config = rustc_interface::Config {
+        // Command line options
+        opts: config::Options::default(),
+        // cfg! configuration in addition to the default ones
+        crate_cfg: Vec::new(),       // FxHashSet<(String, Option<String>)>
+        crate_check_cfg: Vec::new(), // CheckCfg
+        input: config::Input::Str {
+            name: rustc_span::FileName::Custom("main.rs".into()),
+            input: r#"
+static HELLO: &str = "Hello, world!";
+fn main() {
+    println!("{HELLO}");
+}
+"#
+            .into(),
+        },
+        output_dir: None,  // Option<PathBuf>
+        output_file: None, // Option<PathBuf>
+        file_loader: None, // Option<Box<dyn FileLoader + Send + Sync>>
+        locale_resources: rustc_driver::DEFAULT_LOCALE_RESOURCES.to_owned(),
+        lint_caps: FxHashMap::default(), // FxHashMap<lint::LintId, lint::Level>
+        // This is a callback from the driver that is called when [`ParseSess`] is created.
+        psess_created: None, //Option<Box<dyn FnOnce(&mut ParseSess) + Send>>
+        // This is a callback from the driver that is called when we're registering lints;
+        // it is called during plugin registration when we have the LintStore in a non-shared state.
+        //
+        // Note that if you find a Some here you probably want to call that function in the new
+        // function being registered.
+        register_lints: None, // Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>>
+        // This is a callback from the driver that is called just after we have populated
+        // the list of queries.
+        //
+        // The second parameter is local providers and the third parameter is external providers.
+        override_queries: None, // Option<fn(&Session, &mut ty::query::Providers<'_>, &mut ty::query::Providers<'_>)>
+        // Registry of diagnostics codes.
+        registry: registry::Registry::new(rustc_errors::codes::DIAGNOSTICS),
+        make_codegen_backend: None,
+        expanded_args: Vec::new(),
+        ice_file: None,
+        hash_untracked_state: None,
+        using_internal_features: Arc::default(),
+    };
+    rustc_interface::run_compiler(config, |compiler| {
+        // Parse the program and print the syntax tree.
+        let krate = rustc_interface::passes::parse(&compiler.sess);
+        println!("{krate:?}");
+        // Analyze the program and inspect the types of definitions.
+        rustc_interface::create_and_enter_global_ctxt(&compiler, krate, |tcx| {
+            for id in tcx.hir().items() {
+                let hir = tcx.hir();
+                let item = hir.item(id);
+                match item.kind {
+                    rustc_hir::ItemKind::Static(_, _, _) | rustc_hir::ItemKind::Fn(_, _, _) => {
+                        let name = item.ident;
+                        let ty = tcx.type_of(item.hir_id().owner.def_id);
+                        println!("{name:?}:\t{ty:?}")
+                    }
+                    _ => (),
+                }
+            }
+        });
+    });
+}