fixes #26023; incorrect sink requires a copy

compiler/modulegraphs.nim

@@ -606,10 +606,16 @@ proc setHookDisamb*(g: ModuleGraph; hook: PSym; opName: string; typ: PType) =
       break
   hook.disamb = h
 
-proc hasDisabledAsgn*(g: ModuleGraph; t: PType): bool =
-  let op = getAttachedOp(g, t, attachedAsgn)
+proc hasDisabledOp(g: ModuleGraph; t: PType; kind: TTypeAttachedOp): bool =
+  let op = getAttachedOp(g, t, kind)
   result = op != nil and sfError in op.flags
 
+proc hasDisabledAsgn*(g: ModuleGraph; t: PType): bool =
+  result = hasDisabledOp(g, t, attachedAsgn)
+
+proc hasDisabledDup*(g: ModuleGraph; t: PType): bool =
+  result = hasDisabledOp(g, t, attachedDup)
+
 proc copyTypeProps*(g: ModuleGraph; module: int; dest, src: PType) =
   for k in low(TTypeAttachedOp)..high(TTypeAttachedOp):
     let op = getAttachedOp(g, src, k)

compiler/varpartitions.nim

@@ -1024,8 +1024,8 @@ proc computeCursors*(s: PSym; n: PNode; g: ModuleGraph) =
         v.sym.flags * {sfThread, sfGlobal} == {} and
         (hasDestructor(v.sym.typ) or (jsCursors and jsDeepCopied(v.sym.typ))) and
         v.sym.typ.skipTypes({tyGenericInst, tyAlias}).kind != tyOwned and
-        (getAttachedOp(g, v.sym.typ, attachedAsgn) == nil or
-        sfError notin getAttachedOp(g, v.sym.typ, attachedAsgn).flags):
+        not hasDisabledAsgn(g, v.sym.typ) and
+        not hasDisabledDup(g, v.sym.typ):
       let rid = root(par, i)
       if par.s[rid].con.kind == isRootOf and dangerousMutation(par.graphs[par.s[rid].con.graphIndex], par.s[i]):
         discard "cannot cursor into a graph that is mutated"

tests/arc/torcmisc.nim

@@ -65,3 +65,17 @@ method handleConn*(myParam: PubSub,
                   proto: string) {.base, async.} =
   myParam.peers.withValue(conn.peerInfo.peerId, peer):
     let peerB = peer[]
+
+
+
+block:
+  type M = object
+
+  proc `=dup`(_: M): M {.error.}
+  proc take(_: sink M) = discard
+
+  proc test() =
+    var value: M
+    take(value)
+
+  test()