From b19113426f05c65d2693b793cf55d83df030376a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <danielm77@spray.se>
Date: Sat, 17 Apr 2010 11:16:05 +0200
Subject: [PATCH] Unused struct member: Fixed false positives

---
 lib/checkother.cpp     |  6 ++++++
 test/testunusedvar.cpp | 43 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 5575a5bc6..7d35b47bd 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -995,6 +995,12 @@ void CheckOther::checkStructMemberUsage()
 
         if (Token::Match(tok, "struct|union %type% {"))
         {
+            structname.clear();
+            if (Token::simpleMatch(tok->previous(), "extern"))
+                continue;
+            if ((!tok->previous() || Token::simpleMatch(tok->previous(), ";")) && Token::Match(tok->tokAt(2)->link(), ("} ; " + tok->strAt(1) + " %var% ;").c_str()))
+                continue;
+
             structname = tok->strAt(1);
 
             // Bail out if struct/union contain any functions
diff --git a/test/testunusedvar.cpp b/test/testunusedvar.cpp
index 6927ded00..a4b48c87f 100644
--- a/test/testunusedvar.cpp
+++ b/test/testunusedvar.cpp
@@ -60,6 +60,7 @@ private:
         TEST_CASE(structmember6);
         TEST_CASE(structmember7);
         TEST_CASE(structmember8);
+        TEST_CASE(structmember_extern);		// No false positives for extern structs
 
         TEST_CASE(localvar1);
         TEST_CASE(localvar2);
@@ -247,6 +248,48 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void structmember_extern()
+    {
+        // extern struct => no false positive
+        check("extern struct AB\n"
+              "{\n"
+              "    int a;\n"
+              "    int b;\n"
+              "} ab;\n"
+              "\n"
+              "void foo()\n"
+              "{\n"
+              "    ab.b = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // global linkage => no false positive
+        check("struct AB\n"
+              "{\n"
+              "    int a;\n"
+              "    int b;\n"
+              "} ab;\n"
+              "\n"
+              "void foo()\n"
+              "{\n"
+              "    ab.b = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        // static linkage => error message
+        check("static struct AB\n"
+              "{\n"
+              "    int a;\n"
+              "    int b;\n"
+              "} ab;\n"
+              "\n"
+              "void foo()\n"
+              "{\n"
+              "    ab.b = 0;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (style) struct or union member 'AB::a' is never used\n", errout.str());
+    }
+