start on guide reorg

Author: mark-i-m

src/SUMMARY.md

@@ -33,7 +33,8 @@
         - ["Cleanup Crew" ICE-breakers](ice-breaker/cleanup-crew.md)
         - [LLVM ICE-breakers](ice-breaker/llvm.md)
     - [Licenses](./licenses.md)
-- [Part 2: How rustc works](./part-2-intro.md)
+
+- [Part 2: High-level Compiler Architecture](./part-2-intro.md)
     - [High-level overview of the compiler source](./high-level-overview.md)
     - [The Rustc Driver and Interface](./rustc-driver.md)
         - [Rustdoc](./rustdoc.md)
@@ -45,15 +46,24 @@
         - [Profiling Queries](./queries/profiling.md)
         - [Salsa](./salsa.md)
     - [Memory Management in Rustc](./memory.md)
+
+- [Part 3: The Compiler Frontend](./part-3-intro.md)
     - [Lexing and Parsing](./the-parser.md)
     - [`#[test]` Implementation](./test-implementation.md)
     - [Panic Implementation](./panic-implementation.md)
     - [Macro expansion](./macro-expansion.md)
     - [Name resolution](./name-resolution.md)
+    - [AST Validation](./ast-validation.md)
     - [The HIR (High-level IR)](./hir.md)
         - [Lowering AST to HIR](./lowering.md)
         - [Debugging](./hir-debugging.md)
+    - [The MIR (Mid-level IR)](./mir/index.md)
+        - [HAIR MIR construction](./mir/construction.md)
+        - [MIR visitor and traversal](./mir/visitor.md)
+        - [MIR passes: getting the MIR for a function](./mir/passes.md)
     - [Closure expansion](./closure.md)
+
+- [Part 4: The Type System](./part-4-intro.md)
     - [The `ty` module: representing types](./ty.md)
         - [Generics and substitutions](./generics.md)
         - [`TypeFolder` and `TypeFoldable`](./ty-fold.md)
@@ -81,12 +91,7 @@
         - [Method Lookup](./method-lookup.md)
         - [Variance](./variance.md)
         - [Opaque Types](./opaque-types-type-alias-impl-trait.md)
-    - [The MIR (Mid-level IR)](./mir/index.md)
-        - [MIR construction](./mir/construction.md)
-        - [MIR visitor and traversal](./mir/visitor.md)
-        - [MIR passes: getting the MIR for a function](./mir/passes.md)
-        - [MIR optimizations](./mir/optimizations.md)
-        - [Debugging](./mir/debugging.md)
+    - [Pattern and Exhaustiveness Checking](./pat-exhaustive-checking.md)
     - [The borrow checker](./borrow_check.md)
         - [Tracking moves and initialization](./borrow_check/moves_and_initialization.md)
             - [Move paths](./borrow_check/moves_and_initialization/move_paths.md)
@@ -99,9 +104,14 @@
             - [Closure constraints](./borrow_check/region_inference/closure_constraints.md)
             - [Error reporting](./borrow_check/region_inference/error_reporting.md)
         - [Two-phase-borrows](./borrow_check/two_phase_borrows.md)
+    - [Parameter Environments](./param_env.md)
+
+- [Part 5: The Compiler Backend](./part-5-intro.md)
+    - [The MIR (Mid-level IR)](./mir/index.md)
+        - [MIR optimizations](./mir/optimizations.md)
+        - [Debugging](./mir/debugging.md)
     - [Constant evaluation](./const-eval.md)
         - [miri const evaluator](./miri.md)
-    - [Parameter Environments](./param_env.md)
     - [Compiler Backend](./backend/backend.md)
         - [Monomorphization](./backend/monomorph.md)
         - [Lowering MIR](./backend/lowering-mir.md)

src/about-this-guide.md

@@ -2,14 +2,19 @@
 
 This guide is meant to help document how rustc – the Rust compiler –
 works, as well as to help new contributors get involved in rustc
-development. It is not meant to replace code documentation – each
-chapter gives only high-level details, the kinds of things that
-(ideally) don't change frequently.
-
-There are three parts to this guide. Part 1 contains information that should
-be useful no matter how you are contributing. Part 2 contains information
-about how the compiler works. Finally, there are some appendices at the
-end with useful reference information.
+development.
+
+There are six parts to this guide:
+
+1. Contains information that should be useful no matter how you are
+   contributing, such as procedures for contribution, building the compiler,
+   etc.
+2. Discusses the high-level architecture of the compiler, especially the query
+   system.
+3. Discusses the compiler frontend and internal representations.
+4. Discusses the type system.
+5. Discusses the compiler backend, code generation, linking, and debug info.
+6. Appendices at the end with useful reference information.
 
 The guide itself is of course open-source as well, and the sources can
 be found at the [GitHub repository]. If you find any mistakes in the

src/mir/construction.md

@@ -1,4 +1,4 @@
-# MIR construction
+# HAIR and MIR construction
 
 The lowering of [HIR] to [MIR] occurs for the following (probably incomplete)
 list of items: