From d8aeabaee103bc1788ee237c6bdcd4c345923963 Mon Sep 17 00:00:00 2001
From: Yacin Tmimi <yacintmimi@gmail.com>
Date: Thu, 26 Jan 2023 13:50:02 -0500
Subject: [PATCH] include block label length when calculating pat_shape of a
 match arm

Previously we alwasy assumed the match arm pattern would have
`shape.width` - 5 characters of space to work with.

Now if we're formatting a block expression with a label we'll take the
label into account.
---
 src/matches.rs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/matches.rs b/src/matches.rs
index aac5e59b860..fe9e7836ba7 100644
--- a/src/matches.rs
+++ b/src/matches.rs
@@ -246,8 +246,18 @@ fn rewrite_match_arm(
     };
 
     // Patterns
-    // 5 = ` => {`
-    let pat_shape = shape.sub_width(5)?.offset_left(pipe_offset)?;
+    let pat_shape = match &arm.body.kind {
+        ast::ExprKind::Block(_, Some(label)) => {
+            // Some block with a label ` => 'label: {`
+            // 7 = ` => : {`
+            let label_len = label.ident.as_str().len();
+            shape.sub_width(7 + label_len)?.offset_left(pipe_offset)?
+        }
+        _ => {
+            // 5 = ` => {`
+            shape.sub_width(5)?.offset_left(pipe_offset)?
+        }
+    };
     let pats_str = arm.pat.rewrite(context, pat_shape)?;
 
     // Guard