Add pending test

Author: odersky

tests/pending/pos/i4987.scala

@@ -0,0 +1,18 @@
+object Foo {
+
+  class Expr[T]
+
+  abstract class Liftable[T] {
+    def toExpr(x: T): Expr[T]
+  }
+
+  implicit class LiftExprOps[T](val x: T) extends AnyVal {
+    def toExpr(implicit ev: Liftable[T]): Expr[T] = ev.toExpr(x)
+  }
+
+  implicit def NilIsLiftable: Liftable[Nil.type] = ???
+
+  Nil.toExpr(NilIsLiftable)
+  (Nil.toExpr: Expr[Nil.type])
+  Nil.toExpr
+}