Fix #1679: Regression test for compiler crash

Author: nicolasstucki

tests/neg/i1679.scala

@@ -0,0 +1,5 @@
+class A[T]
+object o {
+  // Testing compiler crash, this test should be modified when named type argument are completely implemented
+  val x: A[T=Int, T=Int] = ??? // error: ']' expected, but '=' found
+}