From f5ad7482a8a30ca0cbe85de9b8dfbe393964d465 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sun, 18 Dec 2016 22:10:30 +0100
Subject: [PATCH] CheckBufferOverrun: Skip warnings about array index out of
 bounds in unions. Theoretically, the array is at least as large as the
 biggest union member.

---
 lib/checkbufferoverrun.cpp | 3 +++
 test/testbufferoverrun.cpp | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/lib/checkbufferoverrun.cpp b/lib/checkbufferoverrun.cpp
index 50374574c..03e1832bc 100644
--- a/lib/checkbufferoverrun.cpp
+++ b/lib/checkbufferoverrun.cpp
@@ -1507,6 +1507,9 @@ void CheckBufferOverrun::bufferOverrun()
             if (var->dimension(0) <= 1 && Token::simpleMatch(var->nameToken()->linkAt(1),"] ; }"))
                 continue;
 
+            if (var->scope() && var->scope()->type == Scope::eUnion)
+                continue;
+
             ArrayInfo arrayInfo(var, symbolDatabase);
             arrayInfo.varname(varname);
 
diff --git a/test/testbufferoverrun.cpp b/test/testbufferoverrun.cpp
index 6573c0b39..d931074c6 100644
--- a/test/testbufferoverrun.cpp
+++ b/test/testbufferoverrun.cpp
@@ -563,6 +563,12 @@ private:
               "    ab->a[0] = 0;\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        check("union { char a[1]; int b; } ab;\n"
+              "void f() {\n"
+              "    ab.a[2] = 0;\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
     }