From 2fe6e23138d990a852a59d9680847cb6718565bb Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 31 Mar 2020 14:52:20 +0200
Subject: When adding match arm, don't let the floating comma

---
 crates/ra_syntax/src/ast/edit.rs | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

(limited to 'crates/ra_syntax/src')

diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index 3d023f189..b69cae234 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -369,21 +369,32 @@ impl ast::MatchArmList {
 
     #[must_use]
     pub fn remove_placeholder(&self) -> ast::MatchArmList {
-        let placeholder = self.arms().find(|arm| {
-            if let Some(ast::Pat::PlaceholderPat(_)) = arm.pat() {
-                return true;
-            }
-            false
-        });
+        let placeholder =
+            self.arms().find(|arm| matches!(arm.pat(), Some(ast::Pat::PlaceholderPat(_))));
         if let Some(placeholder) = placeholder {
-            let s: SyntaxElement = placeholder.syntax().clone().into();
-            let e = s.clone();
-            self.replace_children(s..=e, &mut iter::empty())
+            self.remove_arm(&placeholder)
         } else {
             self.clone()
         }
     }
 
+    #[must_use]
+    fn remove_arm(&self, arm: &ast::MatchArm) -> ast::MatchArmList {
+        let start = arm.syntax().clone();
+        let end = if let Some(comma) = start
+            .siblings_with_tokens(Direction::Next)
+            .skip(1)
+            .skip_while(|it| it.kind().is_trivia())
+            .next()
+            .filter(|it| it.kind() == T![,])
+        {
+            comma
+        } else {
+            start.clone().into()
+        };
+        self.replace_children(start.into()..=end, None)
+    }
+
     #[must_use]
     pub fn append_arm(&self, item: ast::MatchArm) -> ast::MatchArmList {
         let r_curly = match self.syntax().children_with_tokens().find(|it| it.kind() == T!['}']) {
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