From 9e125ce46f987bc545aa36213dc7b396474ab176 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 19 Oct 2024 20:47:18 -0700
Subject: [PATCH] Reorder precise captured params to print lifetimes before
 idents

---
 src/generics.rs | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/generics.rs b/src/generics.rs
index bbc32d3ed4..ef1c52f0ea 100644
--- a/src/generics.rs
+++ b/src/generics.rs
@@ -1338,7 +1338,26 @@ pub(crate) mod printing {
         fn to_tokens(&self, tokens: &mut TokenStream) {
             self.use_token.to_tokens(tokens);
             self.lt_token.to_tokens(tokens);
-            self.params.to_tokens(tokens);
+
+            // Print lifetimes before types and consts, regardless of their
+            // order in self.params.
+            let mut trailing_or_empty = true;
+            for param in self.params.pairs() {
+                if let CapturedParam::Lifetime(_) = **param.value() {
+                    param.to_tokens(tokens);
+                    trailing_or_empty = param.punct().is_some();
+                }
+            }
+            for param in self.params.pairs() {
+                if let CapturedParam::Ident(_) = **param.value() {
+                    if !trailing_or_empty {
+                        <Token![,]>::default().to_tokens(tokens);
+                        trailing_or_empty = true;
+                    }
+                    param.to_tokens(tokens);
+                }
+            }
+
             self.gt_token.to_tokens(tokens);
         }
     }