From ee4a219012ca1fcb2cfb2cce4e87ff6774009d86 Mon Sep 17 00:00:00 2001
From: SirOlaf <34164198+SirOlaf@users.noreply.github.com>
Date: Thu, 7 Sep 2023 05:46:45 +0200
Subject: [PATCH] Fix #17509: Continue instead of return with unfinished
 generics (#22563)

Close #17509

Current knowledge:
- delaying cache fixes the issue
- changing return of `if inst.len < key.len:` in `searchInstTypes` to
`continue` fixes the issue. With return the broken types are also cached
over and over

Related issues are completely unaffected as of now, so there must be
something deeper.

I am also still trying to find the true cause, so feel free to ignore
for now

---------

Co-authored-by: SirOlaf <>
---
 compiler/semtypinst.nim   |  3 ++-
 tests/generics/t17509.nim | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 tests/generics/t17509.nim

diff --git a/compiler/semtypinst.nim b/compiler/semtypinst.nim
index bd2b25c24e..4ab0e2de10 100644
--- a/compiler/semtypinst.nim
+++ b/compiler/semtypinst.nim
@@ -45,7 +45,8 @@ proc searchInstTypes*(g: ModuleGraph; key: PType): PType =
       # XXX: This happens for prematurely cached
       # types such as Channel[empty]. Why?
       # See the notes for PActor in handleGenericInvocation
-      return
+      # if this is return the same type gets cached more than it needs to
+      continue
     if not sameFlags(inst, key):
       continue
 
diff --git a/tests/generics/t17509.nim b/tests/generics/t17509.nim
new file mode 100644
index 0000000000..89f507577d
--- /dev/null
+++ b/tests/generics/t17509.nim
@@ -0,0 +1,25 @@
+type List[O] = object
+  next: ptr List[O]
+
+proc initList[O](l: ptr List[O]) =
+  l[].next = l
+
+type
+  PolytopeVertex[R] = object
+    list: List[PolytopeVertex[R]]
+
+  PolytopeEdge[R] = object
+    list: List[PolytopeEdge[R]]
+
+  Polytope[R] = object
+    vertices: List[PolytopeVertex[R]]
+    edges: List[PolytopeEdge[R]]
+
+var pt: Polytope[float]
+
+static:
+  doAssert pt.vertices.next is (ptr List[PolytopeVertex[float]])
+  doAssert pt.edges.next is (ptr List[PolytopeEdge[float]])
+
+initList(addr pt.vertices)
+initList(addr pt.edges)
\ No newline at end of file