Merge pull request #7946 from dotty-staging/fix-#6693

Fix #6693: Add regression test

Author: OlivierBlanvillain

tests/pos/i6693.scala

@@ -0,0 +1,16 @@
+package towers.computes
+
+import quoted._
+
+sealed abstract class Computes[T]
+
+object Computes {
+
+  opaque type Opaque[T] = Int
+
+  implicit class ComputesApplication1[T : Type](fn : Computes[Opaque[T]]) {
+    def apply[A](arg1 : Computes[A]) : Computes[T] = ???
+  }
+
+  def let[V, T : Type](value : Computes[V], body : Computes[Opaque[T]]) : Computes[T] = body(value)
+}