Merge pull request #1912 from retronym/ticket/6651

SI-6651 Extension methods types may depend on the typed of the wrapped value

1 files changed, 33 insertions, 0 deletions

diff --git a/test/files/pos/t6651.scala b/test/files/pos/t6651.scala
new file mode 100644
index 0000000000..55a3b74e4c
--- /dev/null
+++ b/test/files/pos/t6651.scala
@@ -0,0 +1,33 @@
+class YouAreYourself[A <: AnyRef](val you: A) extends AnyVal {
+  def yourself: you.type = you
+}
+
+object Test {
+  val s = ""
+  val s1: s.type = new YouAreYourself[s.type](s).yourself
+}
+
+trait Path {
+  type Dep <: AnyRef
+}
+
+final class ValueClass[P <: Path](val path: P) extends AnyVal {
+  import path.Dep
+
+  def apply(dep: Dep)(d2: dep.type, foo: Int): (Dep, d2.type) = (d2, d2)
+
+  // This generates dodgy code; note `ValueClass.this`:
+  //
+  // final def bounds$extension[D >: Nothing <: ValueClass.this.path.Dep,
+  //                            P >: Nothing <: Path]
+  //                            ($this: ValueClass[P])
+  //                            (dep: D)
+  //                            (d2: dep.type, foo: Int): (D, d2.type) = scala.Tuple2.apply[D, d2.type](d2, d2);
+  //
+  // Nothing crashes down the line, but it certainly doesn't conform to best-practices.
+  //
+  // An better alternative would be to add a type parameter for the (singleton) type of
+  // the wrapped value.
+  def bounds[D <: Dep](dep: D)(d2: dep.type, foo: Int): (D, d2.type) = (d2, d2)
+}
+