Merge pull request #4341 from retronym/ticket/9157

SI-9157 Avoid exponential blowup with chained type projections

1 files changed, 13 insertions, 0 deletions

diff --git a/test/files/pos/t9157.scala b/test/files/pos/t9157.scala
new file mode 100644
index 0000000000..e178b5d84d
--- /dev/null
+++ b/test/files/pos/t9157.scala
@@ -0,0 +1,13 @@
+trait Flow[-In, +Out] {
+  type Repr[+O] <: Flow[In, O]
+  def map: Repr[String]
+}
+
+class Test {
+  // typechecking was exponentially slow wrt the number of projections here.
+  def slowFlow(
+    f: Flow[String,String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]#Repr[String]
+  ) = {
+    f.map
+  }
+}