From 75be034d3dbb04d8c860a40025a195c2337a741b Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Wed, 13 Aug 2014 18:31:47 -0700
Subject: [PATCH] fix(frontends/lean/server): crash when INFO is invoked before
 VISIT/LOAD

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
---
 src/frontends/lean/server.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/frontends/lean/server.cpp b/src/frontends/lean/server.cpp
index 584c933db..63d7f2b36 100644
--- a/src/frontends/lean/server.cpp
+++ b/src/frontends/lean/server.cpp
@@ -150,6 +150,7 @@ void server::visit_file(std::string const & fname) {
 }
 
 void server::show_info(unsigned linenum) {
+    check_file();
     update();
     unsigned i = m_file->find(linenum);
     environment const & env = i == 0 ? m_env     : m_file->m_snapshots[i-1].m_env;