use system.move instead of system.shallowCopy if the GC mode requires it

lib/pure/collections/deques.nim

@@ -259,9 +259,11 @@ proc expandIfNeeded[T](deq: var Deque[T]) =
   var cap = deq.mask + 1
   if unlikely(deq.count >= cap):
     var n = newSeq[T](cap * 2)
-    for i, x in pairs(deq): # don't use copyMem because the GC and because it's slower.
-      shallowCopy(n[i], x)
-    shallowCopy(deq.data, n)
+    var i = 0
+    for x in mitems(deq): # don't use copyMem because of the GC and because it's slower.
+      n[i] = move(x)
+      inc i
+    deq.data = move(n)
     deq.mask = cap * 2 - 1
     deq.tail = deq.count
     deq.head = 0

lib/pure/collections/sequtils.nim

@@ -417,7 +417,10 @@ proc keepIf*[T](s: var seq[T], pred: proc(x: T): bool {.closure.})
   for i in 0 ..< len(s):
     if pred(s[i]):
       if pos != i:
-        shallowCopy(s[pos], s[i])
+        when defined(gcDestructors):
+          s[pos] = move(s[i])
+        else:
+          shallowCopy(s[pos], s[i])
       inc(pos)
   setLen(s, pos)
 
@@ -436,7 +439,10 @@ proc delete*[T](s: var seq[T]; first, last: Natural) =
   var j = min(len(s), last+1)
   var newLen = len(s)-j+i
   while i < newLen:
-    s[i].shallowCopy(s[j])
+    when defined(gcDestructors):
+      s[i] = move(s[j])
+    else:
+      s[i].shallowCopy(s[j])
     inc(i)
     inc(j)
   setLen(s, newLen)
@@ -461,7 +467,10 @@ proc insert*[T](dest: var seq[T], src: openArray[T], pos = 0) =
 
   # Move items after `pos` to the end of the sequence.
   while j >= pos:
-    dest[i].shallowCopy(dest[j])
+    when defined(gcDestructors):
+      dest[i] = move(dest[j])
+    else:
+      dest[i].shallowCopy(dest[j])
     dec(i)
     dec(j)
   # Insert items from `dest` into `dest` at `pos`
@@ -519,7 +528,10 @@ template keepItIf*(varSeq: seq, pred: untyped) =
     let it {.inject.} = varSeq[i]
     if pred:
       if pos != i:
-        shallowCopy(varSeq[pos], varSeq[i])
+        when defined(gcDestructors):
+          varSeq[pos] = move(varSeq[i])
+        else:
+          shallowCopy(varSeq[pos], varSeq[i])
       inc(pos)
   setLen(varSeq, pos)
 

lib/pure/collections/setimpl.nim

@@ -92,7 +92,7 @@ proc exclImpl[A](s: var HashSet[A], key: A): bool {.inline.} =
         if isEmpty(s.data[i].hcode): # end of collision cluster; So all done
           return
         r = s.data[i].hcode and msk # "home" location of key@i
-      shallowCopy(s.data[j], s.data[i]) # data[i] will be marked EMPTY next loop
+      s.data[j] = move(s.data[i]) # data[i] will be marked EMPTY next loop
 
 template dollarImpl() {.dirty.} =
   result = "{"

lib/pure/collections/tableimpl.nim

@@ -99,7 +99,7 @@ template delImplIdx(t, i) =
         when defined(js):
           t.data[j] = t.data[i]
         else:
-          shallowCopy(t.data[j], t.data[i]) # data[j] will be marked EMPTY next loop
+          t.data[j] = move(t.data[i]) # data[j] will be marked EMPTY next loop
 
 template delImpl() {.dirty.} =
   var hc: Hash

lib/pure/collections/tables.nim

@@ -540,7 +540,7 @@ proc take*[A, B](t: var Table[A, B], key: A, val: var B): bool =
   var index = rawGet(t, key, hc)
   result = index >= 0
   if result:
-    shallowCopy(val, t.data[index].val)
+    val = move(t.data[index].val)
     delImplIdx(t, index)
 
 proc clear*[A, B](t: var Table[A, B]) =