From 9ba31fb5e69f7ae9b956833f54ace3a1650d9fcb Mon Sep 17 00:00:00 2001
From: tersec <tersec@users.noreply.github.com>
Date: Thu, 10 Oct 2024 12:23:23 +0000
Subject: [PATCH] adjust isomorphicCast to be Nim 2.2-compatible (#6633)

---
 beacon_chain/spec/datatypes/base.nim | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/beacon_chain/spec/datatypes/base.nim b/beacon_chain/spec/datatypes/base.nim
index c9b9e6ff4..4f8849478 100644
--- a/beacon_chain/spec/datatypes/base.nim
+++ b/beacon_chain/spec/datatypes/base.nim
@@ -891,8 +891,9 @@ func getSizeofSig(x: auto, n: int = 0): seq[(string, int, int)] =
 ##
 ## These SHOULD be used in function calls to avoid expensive temporary.
 ## see https://github.com/status-im/nimbus-eth2/pull/2250#discussion_r562010679
-template isomorphicCast*[T, U](x: U): T =
+template isomorphicCast*[T](x: auto): T =
   # Each of these pairs of types has ABI-compatible memory representations.
+  type U = typeof(x)
   static: doAssert (T is ref) == (U is ref)
   when T is ref:
     type