Add test case

Author: odersky

tests/pos/i576.scala

@@ -0,0 +1,18 @@
+class A
+
+object Impl {
+  def foo()(implicit x: A = null): Int = 2
+  def test: Int = {
+    foo()() // ok
+    foo()   // did not work before, does now
+  }
+}
+
+// same with multiple parameters
+object Impl2 {
+  def foo()(implicit ev: Int, x: A = null): Int = 2
+  def test: Int = {
+    implicit val ii: Int = 1
+    foo()
+  }
+}