make quote ast a ref type (#5246)

* make quote ast a ref type
* recursive set flag isRef for quoted ast

tests/vm/tnimnode.nim

@@ -0,0 +1,69 @@
+import macros
+
+proc assertEq(arg0,arg1: string): void =
+  if arg0 != arg1:
+    raiseAssert("strings not equal:\n" & arg0 & "\n" & arg1)
+
+static:
+  # a simple assignment of stmtList to another variable
+  var node: NimNode
+  # an assignment of stmtList into an array
+  var nodeArray: array[1, NimNode]
+  # an assignment of stmtList into a seq
+  var nodeSeq = newSeq[NimNode](1)
+
+
+proc checkNode(arg: NimNode; name: string): void {. compileTime .} =
+  echo "checking ", name
+  
+  assertEq arg.lispRepr , "StmtList(DiscardStmt(Empty()))"
+  
+  node = arg
+  nodeArray = [arg]
+  nodeSeq[0] = arg
+  arg.add newCall(ident"echo", newLit("Hello World"))
+
+  assertEq arg.lispRepr     , """StmtList(DiscardStmt(Empty()), Call(Ident(!"echo"), StrLit(Hello World)))"""
+  assertEq node.lispRepr         , """StmtList(DiscardStmt(Empty()), Call(Ident(!"echo"), StrLit(Hello World)))"""
+  assertEq nodeArray[0].lispRepr , """StmtList(DiscardStmt(Empty()), Call(Ident(!"echo"), StrLit(Hello World)))"""
+  assertEq nodeSeq[0].lispRepr   , """StmtList(DiscardStmt(Empty()), Call(Ident(!"echo"), StrLit(Hello World)))"""
+
+  echo "OK"
+
+static:
+  # the root node that is used to generate the Ast
+  var stmtList: NimNode
+  
+  stmtList = newStmtList(nnkDiscardStmt.newTree(newEmptyNode()))
+  
+  checkNode(stmtList, "direct construction")
+
+
+macro foo(stmtList: untyped): untyped =
+  checkNode(stmtList, "untyped macro argument")
+
+foo:
+  discard
+
+  
+static:
+  stmtList = quote do:
+    discard
+
+  checkNode(stmtList, "create with quote")
+
+
+static:
+  echo "testing body from loop"
+  var loop = quote do:
+    for i in 0 ..< 10:
+      discard
+
+  let innerBody = loop[0][2]
+  innerBody.add newCall(ident"echo", newLit("Hello World"))
+
+  assertEq loop[0][2].lispRepr, innerBody.lispRepr
+
+  echo "OK"
+  
+