fixes #12989

Author: cooldome

compiler/lowerings.nim

@@ -60,7 +60,6 @@ proc lowerTupleUnpacking*(g: ModuleGraph; n: PNode; owner: PSym): PNode =
   var temp = newSym(skTemp, getIdent(g.cache, genPrefix), owner, value.info, g.config.options)
   temp.typ = skipTypes(value.typ, abstractInst)
   incl(temp.flags, sfFromGeneric)
-  incl(temp.flags, sfCursor)
 
   var v = newNodeI(nkVarSection, value.info)
   let tempAsNode = newSymNode(temp)

tests/destructor/t12037.nim

@@ -23,3 +23,12 @@ test()
 import tables
 var t = initTable[string, seq[ptr int]]()
 discard t.hasKeyOrPut("f1", @[])
+
+
+#############################################
+### bug #12989
+proc bug(start: (seq[int], int)) =
+  let (s, i) = start
+
+let input = @[0]
+bug((input, 0))