Edit parsing (cont)

Author: pierwill

src/overview.md

@@ -148,6 +148,27 @@ And the macro parser entry point is [`Parser::parse_nonterminal()`][parse_nonter
 Parsing is performed with a set of `Parser` utility methods including `bump`,
 `check`, `eat`, `expect`, `look_ahead`.
 
+Parsing is organized by the semantic construct that is being parsed. Separate
+`parse_*` methods can be found in [`rustc_parse` `parser`][rustc_parse_parser_dir]
+directory. The source file name follows the construct name. For example, the
+following files are found in the parser:
+
+- `expr.rs`
+- `pat.rs`
+- `ty.rs`
+- `stmt.rs`
+
+This naming scheme is used across many compiler stages. You will find
+either a file or directory with the same name across the parsing, lowering,
+type checking, THIR lowering, and MIR building sources.
+
+Macro expansion, AST validation, name resolution, and early linting also take place
+during this stage.
+
+The parser uses the standard `DiagnosticBuilder` API for error handling, but we
+try to recover, parsing a superset of Rust's grammar, while also emitting an error.
+`rustc_ast::ast::{Crate, Mod, Expr, Pat, ...}` AST nodes are returned from the parser.
+
 
 [String interning]: https://en.wikipedia.org/wiki/String_interning
 [`rustc_lexer`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lexer/index.html