1 files changed, 2 insertions, 0 deletions
diff --git a/src/msvc_helper-win32.cc b/src/msvc_helper-win32.cc
index 78b79b0..d516240 100644
--- a/src/msvc_helper-win32.cc
+++ b/src/msvc_helper-win32.cc
@@ -15,6 +15,7 @@
 #include "msvc_helper.h"
 
 #include <algorithm>
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <windows.h>
@@ -85,6 +86,7 @@ bool CLParser::FilterInputFilename(string line) {
 bool CLParser::Parse(const string& output, const string& deps_prefix,
                      string* filtered_output, string* err) {
   // Loop over all lines in the output to process them.
+  assert(&output != filtered_output);
   size_t start = 0;
   while (start < output.size()) {
     size_t end = output.find_first_of("\r\n", start);