Merge pull request #2045 from dotty-staging/fix-hlist-hmap

Fix type inference for HLists and HMaps

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/pos/t5643.scala b/tests/pos/t5643.scala
new file mode 100644
index 000000000..1ce34ba36
--- /dev/null
+++ b/tests/pos/t5643.scala
@@ -0,0 +1,19 @@
+object TupledEvidenceTest {
+
+  abstract class TupledEvidence[M[_], T0] { type T = T0 }
+
+  implicit def witnessTuple2[M[_], T1, T2](implicit ev1: M[T1], ev2: M[T2]):
+    TupledEvidence[M, (T1, T2)] { type T = (T1, T2) } = sys.error("")
+
+  class GetResult[T]
+
+  implicit val getString: GetResult[String] = new GetResult[String]
+
+  implicit def getTuple[T](implicit w: TupledEvidence[GetResult, T]): GetResult[w.T] = sys.error("")
+
+  def f[T : GetResult] = ""
+
+  f[(String,String)](getTuple[(String, String)])
+
+  f[(String,String)]
+}