From b28a0cd6e68e342aa026e25dcc651cb9bc5007f8 Mon Sep 17 00:00:00 2001
From: Nick Cameron <ncameron@mozilla.com>
Date: Tue, 17 Jul 2018 15:38:50 +1200
Subject: [PATCH] Fix an anomaly with comments and array literals

Closes #2842
---
 src/lists.rs                  | 10 +++++-----
 tests/source/array_comment.rs | 19 +++++++++++++++++++
 tests/target/array_comment.rs | 18 ++++++++++++++++++
 3 files changed, 42 insertions(+), 5 deletions(-)
 create mode 100644 tests/source/array_comment.rs
 create mode 100644 tests/target/array_comment.rs

diff --git a/src/lists.rs b/src/lists.rs
index c415032ad67..0e3baa7c1e1 100644
--- a/src/lists.rs
+++ b/src/lists.rs
@@ -297,17 +297,15 @@ where
                     if formatting.ends_with_newline {
                         trailing_separator = true;
                     }
+                } else if line_len > 0 {
+                    result.push(' ');
+                    line_len += 1;
                 }
 
                 if last && formatting.ends_with_newline {
                     separate = formatting.trailing_separator != SeparatorTactic::Never;
                 }
 
-                if line_len > 0 {
-                    result.push(' ');
-                    line_len += 1;
-                }
-
                 line_len += total_width;
             }
             _ => {}
@@ -341,6 +339,8 @@ where
                     } else {
                         result.push('\n');
                         result.push_str(indent_str);
+                        // This is the width of the item (without comments).
+                        line_len = item.item.as_ref().map_or(0, |str| str.len());
                     }
                 } else {
                     result.push(' ');
diff --git a/tests/source/array_comment.rs b/tests/source/array_comment.rs
new file mode 100644
index 00000000000..87372b2793f
--- /dev/null
+++ b/tests/source/array_comment.rs
@@ -0,0 +1,19 @@
+// Issue 2842
+// The comment should not make the last line shorter
+
+static XXX: [i8; 64] = [
+    1, // Comment
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
+
+static XXX: [i8; 64] = [
+    1,
+    // Comment
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
+
+static XXX: [i8; 64] = [
+    1,
+    // Comment
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
diff --git a/tests/target/array_comment.rs b/tests/target/array_comment.rs
new file mode 100644
index 00000000000..93e1f5f4034
--- /dev/null
+++ b/tests/target/array_comment.rs
@@ -0,0 +1,18 @@
+// Issue 2842
+// The comment should not make the last line shorter
+
+static XXX: [i8; 64] = [
+    1, // Comment
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
+
+static XXX: [i8; 64] = [
+    1, // Comment
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
+
+static XXX: [i8; 64] = [
+    1, // Comment
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+    1,
+];