From 36e2cb045685c86d88ef57551aa9862a9dc74202 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Campinas?= <stephane.campinas@gmail.com>
Date: Wed, 19 Dec 2018 09:24:02 +0100
Subject: [PATCH 1/2] add a section to the Contributing.md file about
 version-gating formatting changes

---
 Contributing.md | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Contributing.md b/Contributing.md
index 3daaa3dd11e..1cf6a86e546 100644
--- a/Contributing.md
+++ b/Contributing.md
@@ -91,6 +91,31 @@ Please try to avoid leaving `TODO`s in the code. There are a few around, but I
 wish there weren't. You can leave `FIXME`s, preferably with an issue number.
 
 
+### Version-gate formatting changes
+
+A change that introduces a different code-formatting should be gated on the
+`version` configuration. This is to ensure the formatting of the current major
+release is preserved, while allowing fixes to be implemented for the next
+release.
+
+This is done by conditionally guarding the change like so:
+
+```rust
+if config.version() == Version::One { // if the current major release is 1.x
+    // current formatting
+} else {
+    // new formatting
+}
+```
+
+This allows the user to apply the next formatting explicitly via the
+configuration, while being stable by default.
+
+When the next major release is done, the code block of the previous formatting
+can be deleted, e.g., the first block in the example above when going from `1.x`
+to `2.x`.
+
+
 ### A quick tour of Rustfmt
 
 Rustfmt is basically a pretty printer - that is, its mode of operation is to

From e3052624933f779e93b287578a61b501f59143a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Campinas?= <stephane.campinas@gmail.com>
Date: Wed, 19 Dec 2018 09:25:04 +0100
Subject: [PATCH 2/2] clarify the version-gate used for the #3229 change

---
 src/matches.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/matches.rs b/src/matches.rs
index 14733eece86..5d3b2dd548b 100644
--- a/src/matches.rs
+++ b/src/matches.rs
@@ -413,12 +413,15 @@ fn rewrite_match_body(
             } else {
                 ""
             };
-            let semicolon =
-                if context.config.version() == Version::Two && semicolon_for_expr(context, body) {
+            let semicolon = if context.config.version() == Version::One {
+                ""
+            } else {
+                if semicolon_for_expr(context, body) {
                     ";"
                 } else {
                     ""
-                };
+                }
+            };
             ("{", format!("{}{}}}{}", semicolon, indent_str, comma))
         } else {
             ("", String::from(","))