From b7248d5988ae4a4498fd900482142151e3ddddd2 Mon Sep 17 00:00:00 2001
From: Donato Sciarra <sciarp@gmail.com>
Date: Sun, 7 Oct 2018 00:05:42 +0200
Subject: [PATCH] Fix internal compiler error on malformed match arm pattern.
 Issue: 54379

---
 src/libsyntax/parse/parser.rs          |  3 +++
 src/test/ui/resolve/issue-54379.rs     | 21 +++++++++++++++++++++
 src/test/ui/resolve/issue-54379.stderr | 24 ++++++++++++++++++++++++
 3 files changed, 48 insertions(+)
 create mode 100644 src/test/ui/resolve/issue-54379.rs
 create mode 100644 src/test/ui/resolve/issue-54379.stderr

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index d653ed819fddd..03decd584514d 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -3866,6 +3866,9 @@ impl<'a> Parser<'a> {
             // check that a comma comes after every field
             if !ate_comma {
                 let err = self.struct_span_err(self.prev_span, "expected `,`");
+                if let Some(mut delayed) = delayed_err {
+                    delayed.emit();
+                }
                 return Err(err);
             }
             ate_comma = false;
diff --git a/src/test/ui/resolve/issue-54379.rs b/src/test/ui/resolve/issue-54379.rs
new file mode 100644
index 0000000000000..24aa758ea6c23
--- /dev/null
+++ b/src/test/ui/resolve/issue-54379.rs
@@ -0,0 +1,21 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+struct MyStruct {
+    pub s1: Option<String>,
+}
+
+fn main() {
+    let thing = MyStruct { s1: None };
+
+    match thing {
+        MyStruct { .., Some(_) } => {},
+        _ => {}
+    }
+}
diff --git a/src/test/ui/resolve/issue-54379.stderr b/src/test/ui/resolve/issue-54379.stderr
new file mode 100644
index 0000000000000..d1d693a3817b9
--- /dev/null
+++ b/src/test/ui/resolve/issue-54379.stderr
@@ -0,0 +1,24 @@
+error: expected `}`, found `,`
+  --> $DIR/issue-54379.rs:18:22
+   |
+LL |         MyStruct { .., Some(_) } => {},
+   |                    --^
+   |                    | |
+   |                    | expected `}`
+   |                    `..` must be at the end and cannot have a trailing comma
+
+error: expected `,`
+  --> $DIR/issue-54379.rs:18:24
+   |
+LL |         MyStruct { .., Some(_) } => {},
+   |                        ^^^^
+
+error[E0027]: pattern does not mention field `s1`
+  --> $DIR/issue-54379.rs:18:9
+   |
+LL |         MyStruct { .., Some(_) } => {},
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^ missing field `s1`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0027`.