From 0ea204a5ff39564b51bf9710c45ead44f9796c28 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 28 Apr 2025 06:33:22 +1000
Subject: Add useful comments on `ExprKind::If` variants.

Things that aren't obvious and took me a while to work out.
---
 compiler/rustc_middle/src/thir.rs | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'compiler/rustc_middle/src')

diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index 086ec529f33..b9a014d14c0 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -292,7 +292,10 @@ pub enum ExprKind<'tcx> {
     If {
         if_then_scope: region::Scope,
         cond: ExprId,
+        /// `then` is always `ExprKind::Block`.
         then: ExprId,
+        /// If present, the `else_opt` expr is always `ExprKind::Block` (for
+        /// `else`) or `ExprKind::If` (for `else if`).
         else_opt: Option<ExprId>,
     },
     /// A function call. Method calls and overloaded operators are converted to plain function calls.
-- 
cgit 1.4.1-3-g733a5