Merge pull request #13636 from dotty-staging/fix-12944

Fix #12944: Add regression test

Author: OlivierBlanvillain

tests/pos/12944/12944_1.scala

@@ -0,0 +1,11 @@
+object Test1 {
+ type ++[L, R] = (L, R) match
+ case (Int, Int) => 2
+ case (String, String) => "2"
+ case (String, Int) => "2"
+ case (Int, String) => "2"
+
+ type Bar[W <: Int] = W ++ "" ++ W
+
+ val works = summon[Bar[2] =:= "2"]
+}

tests/pos/12944/12944_2.scala

@@ -0,0 +1,5 @@
+import Test1._
+
+object Test2 {
+ val fails = summon[Bar[2] =:= "2"]
+}