From 6828effd1358bab75e17f23ef91de44f4f433a53 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Sat, 27 Jun 2026 01:57:03 +0800
Subject: [PATCH] Improve effect propagation by skipping hooks in trackCall
 (#25940)

ref https://github.com/nim-lang/Nim/pull/25731
don't propagate effects for assignment hooks without effect lists
---
 compiler/sempass2.nim    |  4 +++-
 tests/effects/thooks.nim | 10 +++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim
index 8c740f54bf..008f2317ba 100644
--- a/compiler/sempass2.nim
+++ b/compiler/sempass2.nim
@@ -1197,7 +1197,9 @@ proc trackCall(tracked: PEffects; n: PNode) =
         else:
           if laxEffects notin tracked.c.config.legacyFeatures and a.kind == nkSym and
               a.sym.kind in routineKinds:
-            propagateEffects(tracked, n, a.sym)
+            let (isHook, opKind) = findHookKind(a.sym.name.s)
+            if (not isHook) or opKind notin {attachedAsgn, attachedSink, attachedDup}:
+              propagateEffects(tracked, n, a.sym)
       else:
         mergeRaises(tracked, effectList[exceptionEffects], n)
         mergeTags(tracked, effectList[tagEffects], n)
diff --git a/tests/effects/thooks.nim b/tests/effects/thooks.nim
index 23cc005cd1..393f8eff74 100644
--- a/tests/effects/thooks.nim
+++ b/tests/effects/thooks.nim
@@ -13,4 +13,12 @@ proc send(x: string) =
   let wrapper = Thing(x: x)
   discard isolate(wrapper)
 
-send("la")
\ No newline at end of file
+send("la")
+
+block:
+  func enqueue[T](buf: var array[10, T], elem: sink T) =
+    `=sink`(buf[0], elem)
+
+  var buf: array[10, int]
+  enqueue(buf, 42)
+  assert buf[0] == 42
\ No newline at end of file