From 2fee89f7db54e1425ba43c3d9a5eb4156eb6c765 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arne=20D=C3=B6ring?= <arne.doering@gmx.net>
Date: Sun, 9 Feb 2020 13:51:36 +0100
Subject: [PATCH] fix #13255 (#13275) [backport]

---
 compiler/semstmts.nim | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 69022f4ad0..7636705e0e 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -945,9 +945,9 @@ proc semCase(c: PContext, n: PNode; flags: TExprFlags): PNode =
       checkSonsLen(x, 1, c.config)
       x[0] = semExprBranchScope(c, x[0])
       typ = commonType(typ, x[0])
-      hasElse = true
-      if chckCovered and covered == toCover(c, n[0].typ):
+      if (chckCovered and covered == toCover(c, n[0].typ)) or hasElse:
         localError(c.config, x.info, "invalid else, all cases are already covered")
+      hasElse = true
       chckCovered = false
     else:
       illFormedAst(x, c.config)