arc: =deepcopy fixes

compiler/varpartitions.nim

@@ -459,7 +459,6 @@ proc traverse(c: var Partitions; n: PNode) =
           if paramType.kind == tyVar:
             if c.inNoSideEffectSection == 0:
               for r in roots: potentialMutation(c, r, it.info)
-          else:
             for r in roots: noCursor(c, r)
 
   of nkAddr, nkHiddenAddr:

lib/system/deepcopy.nim

@@ -140,6 +140,9 @@ proc genericDeepCopyAux(dest, src: pointer, mt: PNimType; tab: var PtrTable) =
       unsureAsgnRef(cast[PPointer](dest), s2)
     elif mt.base.deepcopy != nil:
       let z = mt.base.deepcopy(s2)
+      when defined(nimSeqsV2):
+        cast[PPointer](dest)[] = z
+      else:
         unsureAsgnRef(cast[PPointer](dest), z)
     else:
       let z = tab.get(s2)
@@ -157,9 +160,15 @@ proc genericDeepCopyAux(dest, src: pointer, mt: PNimType; tab: var PtrTable) =
             let x = usrToCell(s2)
             let realType = x.typ
             sysAssert realType == mt, " types do differ"
-          # this version should work for any possible GC:
+          when defined(nimSeqsV2):
+            let typ = if mt.base.kind == tyObject: cast[PNimType](cast[ptr PNimTypeV2](s2)[].typeInfoV1)
+                      else: mt.base
+            let z = nimNewObj(typ.size)
+            cast[PPointer](dest)[] = z
+          else:
+            # this version should work for any other GC:
             let typ = if mt.base.kind == tyObject: cast[ptr PNimType](s2)[] else: mt.base
-          let z = when defined(nimSeqsV2): nimNewObj(typ.size) else: newObj(mt, typ.size)
+            let z = newObj(mt, typ.size)
             unsureAsgnRef(cast[PPointer](dest), z)
           tab.put(s2, z)
           genericDeepCopyAux(z, s2, typ, tab)

tests/arc/tdeepcopy.nim

@@ -0,0 +1,67 @@
+discard """
+  cmd: "nim c --gc:arc $file"
+  output: '''13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+0'''
+"""
+
+type
+  PBinaryTree = ref object of RootObj
+    le, ri: PBinaryTree
+    value: int
+
+proc mainB =
+  var x: PBinaryTree
+  deepCopy(x, PBinaryTree(ri: PBinaryTree(le: PBinaryTree(value: 13))))
+
+  var y: string
+  deepCopy y, "abc"
+  echo x.ri.le.value, " ", y
+
+for i in 0..10:
+  mainB()
+
+
+type
+  Bar[T] = object
+    x: T
+
+proc `=deepCopy`[T](b: ref Bar[T]): ref Bar[T] =
+  result.new
+  result.x = b.x
+  when T is int:
+    echo "called deepCopy for int"
+  else:
+    echo "called deepCopy for something else"
+
+proc main =
+  var dummy, c: ref Bar[int]
+  new(dummy)
+  dummy.x = 44
+
+  deepCopy c, dummy
+
+for i in 0..10:
+  main()
+
+echo getOccupiedMem()