Merge pull request #15333 from griggt/fix-15183

Fix #15183: Add regression test

Author: bishabosha

tests/pos/i15183/decoder_1.scala

@@ -0,0 +1,14 @@
+import scala.deriving._
+
+sealed trait Decoder[T]
+object Decoder {
+  given Decoder[Double] = ???
+
+  inline given summonEmptyTuple[H]: Tuple.Map[EmptyTuple.type, Decoder] =
+    EmptyTuple
+
+  inline given summonTuple[H, T <: Tuple](using hd: Decoder[H], td: Tuple.Map[T, Decoder]): Tuple.Map[H *: T, Decoder] =
+    hd *: td
+
+  inline given derived[T](using m: Mirror.Of[T], d: Tuple.Map[m.MirroredElemTypes, Decoder]): Decoder[T] = ???
+}

tests/pos/i15183/test_2.scala

@@ -0,0 +1,12 @@
+// Fails in each cases below
+enum Env derives Decoder:
+  case Local,Sit,Prod
+
+enum Env2 derives Decoder:
+  case Local()
+  case Sit()
+  case Prod()
+
+enum Shape derives Decoder:
+  case Rectangle(width: Double, height: Double)
+  case Circle(radius: Double)