Decrement depth in subtype check withTypeVars

Fixes scala/bug#7612
joroKr21 · Oct 1, 2018 · d58630a · d58630a
1 parent 7c8b36f
commit d58630a
Show file tree

Hide file tree

Showing 2 changed files with 19 additions and 1 deletion.
diff --git a/src/reflect/scala/reflect/internal/tpe/TypeComparers.scala b/src/reflect/scala/reflect/internal/tpe/TypeComparers.scala
@@ -528,7 +528,7 @@ trait TypeComparers {
         (rt2.parents forall (isSubType(tp1, _, depth))) &&
           (rt2.decls forall (specializesSym(tp1, _, depth)))
       case et2: ExistentialType =>
-        et2.withTypeVars(isSubType(tp1, _, depth), depth) || fourthTry
+        et2.withTypeVars(isSubType(tp1, _, depth), depth.decr) || fourthTry
       case mt2: MethodType =>
         tp1 match {
           case mt1 @ MethodType(params1, res1) =>

diff --git a/test/files/pos/t7612.scala b/test/files/pos/t7612.scala
@@ -0,0 +1,18 @@
+trait Fili[A]
+trait Kili[M] {
+  def fili: Fili[M]
+}
+
+trait A extends Kili[A] {
+  def fili: Fili[A]
+}
+
+trait Ori[M] extends Kili[M] {
+  val ori: Fili[M]
+  def fili: ori.type
+}
+trait B extends Ori[B]
+
+object Test {
+  def foo(a: A, b: B) = if (true) a else b // LUB triggers StackOverflowError
+}