Merge pull request #5816 from adriaanm/userdefined-apply-212

Allow user-defined `[un]apply` in case companion

2 files changed, 67 insertions, 0 deletions

diff --git a/test/files/pos/userdefined_apply.scala b/test/files/pos/userdefined_apply.scala
new file mode 100644
index 0000000000..e29f9f5141
--- /dev/null
+++ b/test/files/pos/userdefined_apply.scala
@@ -0,0 +1,54 @@
+// NOTE: the companion inherits a public apply method from Function1!
+case class NeedsCompanion private (x: Int)
+
+object ClashNoSig { // ok
+  private def apply(x: Int) = if (x > 0) new ClashNoSig(x) else ???
+}
+case class ClashNoSig private (x: Int)
+
+
+object Clash {
+  private def apply(x: Int) = if (x > 0) new Clash(x) else ???
+}
+case class Clash private (x: Int)
+
+object ClashSig {
+  private def apply(x: Int): ClashSig = if (x > 0) new ClashSig(x) else ???
+}
+case class ClashSig private (x: Int)
+
+object ClashOverload {
+  private def apply(x: Int): ClashOverload = if (x > 0) new ClashOverload(x) else apply("")
+  def apply(x: String): ClashOverload = ???
+}
+case class ClashOverload private (x: Int)
+
+object NoClashSig {
+  private def apply(x: Boolean): NoClashSig = if (x) NoClashSig(1) else ???
+}
+case class NoClashSig private (x: Int)
+
+object NoClashOverload {
+  // needs full sig
+  private def apply(x: Boolean): NoClashOverload = if (x) NoClashOverload(1) else apply("")
+  def apply(x: String): NoClashOverload = ???
+}
+case class NoClashOverload private (x: Int)
+
+
+
+class BaseNCP[T] {
+  // error: overloaded method apply needs result type
+  def apply(x: T): NoClashPoly = if (???) NoClashPoly(1) else ???
+}
+
+object NoClashPoly extends BaseNCP[Boolean]
+case class NoClashPoly private(x: Int)
+
+
+class BaseCP[T] {
+  // error: overloaded method apply needs result type
+  def apply(x: T): ClashPoly = if (???) ClashPoly(1) else ???
+}
+object ClashPoly extends BaseCP[Int]
+case class ClashPoly private(x: Int)
diff --git a/test/files/pos/userdefined_apply_poly_overload.scala b/test/files/pos/userdefined_apply_poly_overload.scala
new file mode 100644
index 0000000000..6760c1424f
--- /dev/null
+++ b/test/files/pos/userdefined_apply_poly_overload.scala
@@ -0,0 +1,13 @@
+object Foo {
+  // spurious error if:
+  //   - this definition precedes that of apply (which is overloaded with the synthetic one derived from the case class)
+  //   - AND `Foo.apply` is explicitly applied to `[A]` (no error if `[A]` is inferred)
+  //
+  def referToPolyOverloadedApply[A]: Foo[A] = Foo.apply[A]("bla")
+  //                                                   ^
+  //  found   : String("bla")
+  //  required: Int
+
+  def apply[A](x: Int): Foo[A] = ???
+}
+case class Foo[A](x: String) // must be polymorphic