From 2a8bf470af995f4e7d5bb8a0f49bb2226f95c311 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Sat, 8 Aug 2020 23:08:34 +0200
Subject: [PATCH] fixes #15101 [backport] (#15171)

---
 compiler/semfields.nim | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/compiler/semfields.nim b/compiler/semfields.nim
index a911ae823d..cea084d3ad 100644
--- a/compiler/semfields.nim
+++ b/compiler/semfields.nim
@@ -23,7 +23,7 @@ proc instFieldLoopBody(c: TFieldInstCtx, n: PNode, forLoop: PNode): PNode =
     result = newNode(nkEmpty)
     return
   case n.kind
-  of nkEmpty..pred(nkIdent), succ(nkSym)..nkNilLit: result = n
+  of nkEmpty..pred(nkIdent), succ(nkSym)..nkNilLit: result = copyNode(n)
   of nkIdent, nkSym:
     result = n
     let ident = considerQuotedIdent(c.c, n)
@@ -52,8 +52,7 @@ proc instFieldLoopBody(c: TFieldInstCtx, n: PNode, forLoop: PNode): PNode =
     if n.kind == nkContinueStmt:
       localError(c.c.config, n.info,
                  "'continue' not supported in a 'fields' loop")
-    result = copyNode(n)
-    newSons(result, n.len)
+    result = shallowCopy(n)
     for i in 0..<n.len:
       result[i] = instFieldLoopBody(c, n[i], forLoop)