From 7e8b768398545217ab365df23902dba4756401c3 Mon Sep 17 00:00:00 2001
From: Kevin Amado <kamadorueda@gmail.com>
Date: Mon, 14 Feb 2022 17:29:01 -0500
Subject: [PATCH] feat: avoid extra line on multiline patterns

---
 src/rules/pattern.rs    | 23 +++++++++++++----------
 tests/cases/pattern/in  |  5 +++++
 tests/cases/pattern/out | 18 ++++++++++++------
 3 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/src/rules/pattern.rs b/src/rules/pattern.rs
index dd17f35b..16b8a698 100644
--- a/src/rules/pattern.rs
+++ b/src/rules/pattern.rs
@@ -70,13 +70,15 @@ pub fn rule(
     let child = children.get_next().unwrap();
     steps.push_back(crate::builder::Step::Format(child.element));
 
+    let mut last_kind = rnix::SyntaxKind::TOKEN_CURLY_B_OPEN;
+
     while let Some(child) = children.peek_next() {
-        match child.element.kind() {
+        let kind = child.element.kind();
+        match kind {
             // /**/
             rnix::SyntaxKind::TOKEN_COMMENT => {
-                let prev_kind = children.peek_prev().unwrap().element.kind();
                 if let rnix::SyntaxKind::TOKEN_COMMA
-                | rnix::SyntaxKind::TOKEN_CURLY_B_OPEN = prev_kind
+                | rnix::SyntaxKind::TOKEN_CURLY_B_OPEN = last_kind
                 {
                     steps.push_back(crate::builder::Step::Whitespace);
                     steps.push_back(crate::builder::Step::Indent);
@@ -84,8 +86,7 @@ pub fn rule(
 
                 if let rnix::SyntaxKind::TOKEN_COMMENT
                 | rnix::SyntaxKind::TOKEN_ELLIPSIS
-                | rnix::SyntaxKind::TOKEN_WHITESPACE
-                | rnix::SyntaxKind::NODE_PAT_ENTRY = prev_kind
+                | rnix::SyntaxKind::NODE_PAT_ENTRY = last_kind
                 {
                     steps.push_back(crate::builder::Step::Indent);
                     steps.push_back(crate::builder::Step::NewLine);
@@ -101,24 +102,24 @@ pub fn rule(
                 | rnix::SyntaxKind::TOKEN_COMMENT
                 | rnix::SyntaxKind::TOKEN_ELLIPSIS
                 | rnix::SyntaxKind::TOKEN_WHITESPACE
-                | rnix::SyntaxKind::NODE_PAT_ENTRY = prev_kind
+                | rnix::SyntaxKind::NODE_PAT_ENTRY = last_kind
                 {
                     steps.push_back(crate::builder::Step::Dedent);
                 }
+
+                last_kind = kind;
             }
             // item
             rnix::SyntaxKind::TOKEN_ELLIPSIS
             | rnix::SyntaxKind::NODE_PAT_ENTRY => {
-                let prev_kind = children.peek_prev().unwrap().element.kind();
-
                 if let rnix::SyntaxKind::TOKEN_COMMA
-                | rnix::SyntaxKind::TOKEN_CURLY_B_OPEN = prev_kind
+                | rnix::SyntaxKind::TOKEN_CURLY_B_OPEN = last_kind
                 {
                     steps.push_back(crate::builder::Step::Whitespace);
                 }
 
                 if let rnix::SyntaxKind::TOKEN_COMMENT
-                | rnix::SyntaxKind::TOKEN_WHITESPACE = prev_kind
+                | rnix::SyntaxKind::TOKEN_WHITESPACE = last_kind
                 {
                     steps.push_back(crate::builder::Step::NewLine);
                     steps.push_back(crate::builder::Step::Pad);
@@ -139,6 +140,7 @@ pub fn rule(
                     }
                 };
                 children.move_next();
+                last_kind = kind;
             }
             // ,
             rnix::SyntaxKind::TOKEN_COMMA => {
@@ -151,6 +153,7 @@ pub fn rule(
                 };
                 steps.push_back(crate::builder::Step::Format(child.element));
                 children.move_next();
+                last_kind = kind;
             }
             // \n
             rnix::SyntaxKind::TOKEN_WHITESPACE => {
diff --git a/tests/cases/pattern/in b/tests/cases/pattern/in
index 1c6b7a0e..0fd7c763 100644
--- a/tests/cases/pattern/in
+++ b/tests/cases/pattern/in
@@ -1,4 +1,9 @@
 [
+  ({
+    self,
+    gomod2nix,
+    mach-nix,
+  }@inp: _)
   ({}: _)
   ({ a }: _)
   ({ /**/ }: _)
diff --git a/tests/cases/pattern/out b/tests/cases/pattern/out
index dbfb8a9a..5a58a6f3 100644
--- a/tests/cases/pattern/out
+++ b/tests/cases/pattern/out
@@ -1,4 +1,13 @@
 [
+  (
+    { self
+    , gomod2nix
+    , mach-nix
+    ,
+    }
+    @ inp:
+      _
+  )
   ({ }: _)
   ({ a }: _)
   (
@@ -1096,8 +1105,7 @@
   )
 
   (
-    {
-      /*
+    { /*
        a
        */
       #
@@ -1116,8 +1124,7 @@
        c
        */
       #
-    ,
-      /*
+    , /*
        d
        */
       #
@@ -1136,8 +1143,7 @@
        f
        */
       #
-    ,
-      /*
+    , /*
        g
        */
       #