(pat, ..,) is now syntactically legal.

src/test/ui/parser/pat-tuple-2.rs

@@ -1,6 +1,7 @@
+// check-pass
+
 fn main() {
     match (0, 1, 2) {
         (pat, ..,) => {}
-        //~^ ERROR trailing comma is not permitted after `..`
     }
 }

src/test/ui/parser/pat-tuple-2.stderr

@@ -1,8 +0,0 @@
-error: trailing comma is not permitted after `..`
-  --> $DIR/pat-tuple-2.rs:3:17
-   |
-LL |         (pat, ..,) => {}
-   |                 ^ trailing comma is not permitted after `..`
-
-error: aborting due to previous error
-