Add examples to test partial eta-expansion

Author: b-studios

tests/neg/i2146.scala

@@ -0,0 +1,8 @@
+object Test {
+  case class A()
+  case class B()
+
+  def foo[A, B]: implicit A => implicit B => Int = { implicit b: B =>
+    42 // error: found Int, required: implicit A => implicit B => Int
+  }
+}

tests/pos/i2146.check

@@ -4,3 +4,6 @@
 A()
 (A(),B())
 (A(),B())
+(A(),B())
+(A(),B())
+(A(),B())

tests/pos/i2146.scala

@@ -7,6 +7,10 @@ object Test {
   def foo[A, B]: implicit A => implicit B => (A, B) =
     (implicitly[A], implicitly[B])
 
+  def bar[A, B]: implicit A => implicit B => (A, B) = { implicit a: A =>
+    (implicitly[A], implicitly[B])
+  }
+
   implicit val a: A = A()
   implicit val b: B = B()
 
@@ -20,5 +24,9 @@ object Test {
     println(x0)
     val x1: implicit B => (A, B) = foo[A, B]
     println(x1)
+
+    println(bar[A, B])
+    println(bar[A, B](a))
+    println(bar(a)(b))
   }
 }