--- /dev/null
+; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
+
+; Check the error message on skipping ", ..." at the end of a musttail call argument list.
+
+%struct.A = type { i32 }
+
+declare i8* @f(i8*, ...)
+
+define i8* @f_thunk(i8* %this, ...) {
+ %rv = musttail call i8* (i8*, ...)* @f(i8* %this)
+; CHECK: error: expected '...' at end of argument list for musttail call in varargs function
+ ret i8* %rv
+}