Merge pull request #49 from missingfaktor/master

Avoid instantiating Unit when producing error stack

2 files changed, 12 insertions, 1 deletions

diff --git a/core/shared/src/main/scala/magnolia.scala b/core/shared/src/main/scala/magnolia.scala
index 6400002..d400bc3 100644
--- a/core/shared/src/main/scala/magnolia.scala
+++ b/core/shared/src/main/scala/magnolia.scala
@@ -215,7 +215,8 @@ object Magnolia {
                            typeOf[Int],
                            typeOf[Long],
                            typeOf[Char],
-                           typeOf[Boolean])
+                           typeOf[Boolean],
+                           typeOf[Unit])
 
       val isValueClass = genericType <:< typeOf[AnyVal] && !primitives.exists(_ =:= genericType)
 
diff --git a/tests/src/main/scala/tests.scala b/tests/src/main/scala/tests.scala
index e453502..cf31836 100644
--- a/tests/src/main/scala/tests.scala
+++ b/tests/src/main/scala/tests.scala
@@ -161,6 +161,16 @@ object Tests extends TestApp {
                                       |    in parameter 'alpha' of product type Beta
                                       |"""))
 
+    test("not attempt to instantiate Unit when producing error stack") {
+      scalac"""
+        import magnolia.examples._
+        case class Gamma(unit: Unit)
+        Show.gen[Gamma]
+      """
+    }.assert(_ == TypecheckError(txt"""magnolia: could not find typeclass for type Unit
+                                      |    in parameter 'unit' of product type Gamma
+                                      |"""))
+
     test("typenames and labels are not encoded") {
       implicitly[Show[String, `%%`]].show(`%%`(1, "two"))
     }.assert(_ == "%%(/=1,#=two)")