From ba7c874a7df6e96dee2d7647a3f554d7476d3ae6 Mon Sep 17 00:00:00 2001
From: LemonBoy <LemonBoy@users.noreply.github.com>
Date: Sun, 12 Aug 2018 20:41:48 +0200
Subject: [PATCH] Mysterious fix for #8550 (#8561)

Replacing the `for` body with a nkEmpty node is not the right thing to
do.
---
 compiler/transf.nim     |  7 ++-----
 tests/closure/t8550.nim | 12 ++++++++++++
 2 files changed, 14 insertions(+), 5 deletions(-)
 create mode 100644 tests/closure/t8550.nim

diff --git a/compiler/transf.nim b/compiler/transf.nim
index dae8d1ee6d..c3bc29891a 100644
--- a/compiler/transf.nim
+++ b/compiler/transf.nim
@@ -539,11 +539,8 @@ proc transformFor(c: PTransf, n: PNode): PTransNode =
   if call.kind notin nkCallKinds or call.sons[0].kind != nkSym or
       call.sons[0].typ.callConv == ccClosure:
     n.sons[length-1] = transformLoopBody(c, n.sons[length-1]).PNode
-    if not c.tooEarly:
-      n.sons[length-2] = transform(c, n.sons[length-2]).PNode
-      result[1] = lambdalifting.liftForLoop(c.graph, n, getCurrOwner(c)).PTransNode
-    else:
-      result[1] = newNode(nkEmpty).PTransNode
+    n.sons[length-2] = transform(c, n.sons[length-2]).PNode
+    result[1] = lambdalifting.liftForLoop(c.graph, n, getCurrOwner(c)).PTransNode
     discard c.breakSyms.pop
     return result
 
diff --git a/tests/closure/t8550.nim b/tests/closure/t8550.nim
new file mode 100644
index 0000000000..153246f085
--- /dev/null
+++ b/tests/closure/t8550.nim
@@ -0,0 +1,12 @@
+discard """
+  output: "@[\"42\"]"
+"""
+
+proc chk_fail(): seq[string] =
+  iterator x(): int {.closure.} = yield 42
+  proc f(cl: iterator(): int {.closure.}): seq[string] =
+    result = @[]
+    for i in cl(): result.add($i)
+  result = f(x)
+
+echo(chk_fail())