From 3bfed9e43f5ebe76719e3c30c8c8cefc81b08f80 Mon Sep 17 00:00:00 2001
From: Hidehito Yabuuchi <hdht.ybuc@gmail.com>
Date: Thu, 22 Mar 2018 20:57:12 +0900
Subject: Better diagnostics for '..' pattern fragment not in the last position

---
 src/libsyntax/parse/parser.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'src/libsyntax/parse')

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index a07279acae2..98e2528d30f 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -3675,7 +3675,13 @@ impl<'a> Parser<'a> {
                 if self.token != token::CloseDelim(token::Brace) {
                     let token_str = self.this_token_to_string();
                     let mut err = self.fatal(&format!("expected `{}`, found `{}`", "}", token_str));
-                    err.span_label(self.span, "expected `}`");
+                    if self.token == token::Comma { // Issue #49257
+                        err.span_label(self.span,
+                                       "`..` must be in the last position, \
+                                        and cannot have a trailing comma");
+                    } else {
+                        err.span_label(self.span, "expected `}`");
+                    }
                     return Err(err);
                 }
                 etc = true;
-- 
cgit 1.4.1-3-g733a5