From 7ab84bef0cb4380151da1d126439c674b7c70975 Mon Sep 17 00:00:00 2001
From: IOBYTE <reif@earthlink.net>
Date: Mon, 15 Feb 2021 02:12:29 -0500
Subject: [PATCH] fix daca crash in intel-compute-runtime (#3132)

---
 lib/tokenize.cpp           | 2 +-
 test/testsimplifyusing.cpp | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 1ce451908..0780fd65a 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -2308,7 +2308,7 @@ bool Tokenizer::simplifyUsing()
         const ScopeInfo3 * memberFuncScope = nullptr;
         const Token * memberFuncEnd = nullptr;
         bool skip = false; // don't erase type aliases we can't parse
-        for (Token* tok1 = startToken; tok1 != endToken; tok1 = tok1->next()) {
+        for (Token* tok1 = startToken; tok1 && tok1 != endToken; tok1 = tok1->next()) {
             if ((Token::Match(tok1, "{|}|namespace|class|struct|union") && tok1->strAt(-1) != "using") ||
                 Token::Match(tok1, "using namespace %name% ;|::")) {
                 setScopeInfo(tok1, &currentScope1);
diff --git a/test/testsimplifyusing.cpp b/test/testsimplifyusing.cpp
index 2de0ec692..0b3ec5275 100644
--- a/test/testsimplifyusing.cpp
+++ b/test/testsimplifyusing.cpp
@@ -64,6 +64,7 @@ private:
         TEST_CASE(simplifyUsing15);
         TEST_CASE(simplifyUsing16);
         TEST_CASE(simplifyUsing17);
+        TEST_CASE(simplifyUsing18);
 
         TEST_CASE(simplifyUsing8970);
         TEST_CASE(simplifyUsing8971);
@@ -457,6 +458,11 @@ private:
         ASSERT_EQUALS(expected, tok(code, false));
     }
 
+    void simplifyUsing18() {
+        const char code[] = "{ { { using a = a; using a; } } }";
+        tok(code, false); // don't crash
+    }
+
     void simplifyUsing8970() {
         const char code[] = "using V = std::vector<int>;\n"
                             "struct A {\n"