From 9ccfcf5dd2572c858913cf092a6a571a5e4a8df0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oscar=20Nihlg=C3=A5rd?= <oscarnihlgard@gmail.com>
Date: Thu, 24 Oct 2019 11:04:04 +0200
Subject: [PATCH] Fix compiler crash caused by top level return (#12501)

---
 compiler/semexprs.nim | 2 +-
 tests/misc/t12480.nim | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 tests/misc/t12480.nim

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index ed38f66e11..2e9c5e1f55 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -1724,7 +1724,7 @@ proc semReturn(c: PContext, n: PNode): PNode =
   result = n
   checkSonsLen(n, 1, c.config)
   if c.p.owner.kind in {skConverter, skMethod, skProc, skFunc, skMacro} or
-      isClosureIterator(c.p.owner.typ):
+      (not c.p.owner.typ.isNil and isClosureIterator(c.p.owner.typ)):
     if n.sons[0].kind != nkEmpty:
       # transform ``return expr`` to ``result = expr; return``
       if c.p.resultSym != nil:
diff --git a/tests/misc/t12480.nim b/tests/misc/t12480.nim
new file mode 100644
index 0000000000..992533ef60
--- /dev/null
+++ b/tests/misc/t12480.nim
@@ -0,0 +1,5 @@
+discard """
+  errormsg: "'return' not allowed here"
+"""
+
+return
\ No newline at end of file