From c560260df88d597fb8858603deb233c8212163b9 Mon Sep 17 00:00:00 2001
From: Rahul Goma Phulore <rahul.phulore.999@gmail.com>
Date: Sun, 26 Nov 2017 21:02:58 +0000
Subject: Avoid instantiating Unit when producing error stack

Fixes https://github.com/propensive/magnolia/issues/41.
---
 tests/src/main/scala/tests.scala | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'tests')

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)")
-- 
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