From fb5dc6b3e740e2030710b92a1bae8f8a81b35452 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 22 Aug 2022 13:38:19 +1000
Subject: [PATCH] Add some useful comments to `LitKind`.

---
 compiler/rustc_ast/src/ast.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 598bf771008..f059db916b4 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1751,7 +1751,8 @@ pub enum LitFloatType {
 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
 #[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
 pub enum LitKind {
-    /// A string literal (`"foo"`).
+    /// A string literal (`"foo"`). The symbol is unescaped, and so may differ
+    /// from the original token's symbol.
     Str(Symbol, StrStyle),
     /// A byte string (`b"foo"`).
     ByteStr(Lrc<[u8]>),
@@ -1761,7 +1762,8 @@ pub enum LitKind {
     Char(char),
     /// An integer literal (`1`).
     Int(u128, LitIntType),
-    /// A float literal (`1f64` or `1E10f64`).
+    /// A float literal (`1f64` or `1E10f64`). Stored as a symbol rather than
+    /// `f64` so that `LitKind` can impl `Eq` and `Hash`.
     Float(Symbol, LitFloatType),
     /// A boolean literal.
     Bool(bool),