From 69d03bac3471141af31c707f6fcc2d5f375cedd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <danielm77@spray.se>
Date: Sun, 19 Feb 2012 15:25:46 +0100
Subject: [PATCH] Fixed #3603 (False Positive: Variable is assigned a value
 that is never used)

---
 lib/checkunusedvar.cpp | 27 +++++++++++++++++----------
 test/testunusedvar.cpp | 11 +++++++++++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/lib/checkunusedvar.cpp b/lib/checkunusedvar.cpp
index 075b99039..6b1f1749b 100644
--- a/lib/checkunusedvar.cpp
+++ b/lib/checkunusedvar.cpp
@@ -662,17 +662,24 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             break;
         }
 
-        if (Token::Match(tok, "%type% const| *|&| const| *| const| %var% [;=[(]") && tok->str() != "return" && tok->str() != "throw") { // Declaration: Skip
-            tok = tok->next();
-            while (Token::Match(tok, "const|*|&"))
+        if (Token::Match(tok, "%type% const| *|&| const| *| const| %var% [;=[(]")) { // Declaration: Skip
+            // Before a declaration there should be ;{}
+            const Token *prev = tok;
+            while (prev && prev->isName() && prev->str() != "return" && prev->str() != "throw")
+                prev = prev->previous();
+            if (Token::Match(prev, "[;{}]")) {
+
                 tok = tok->next();
-            tok = Token::findmatch(tok, "[;=[(]");
-            if (tok && Token::Match(tok, "( %var% )")) // Simple initialization through copy ctor
-                tok = tok->next();
-            else if (tok && Token::Match(tok, "= %var% ;")) // Simple initialization
-                tok = tok->next();
-            if (!tok)
-                break;
+                while (Token::Match(tok, "const|*|&"))
+                    tok = tok->next();
+                tok = Token::findmatch(tok, "[;=[(]");
+                if (tok && Token::Match(tok, "( %var% )")) // Simple initialization through copy ctor
+                    tok = tok->next();
+                else if (tok && Token::Match(tok, "= %var% ;")) // Simple initialization
+                    tok = tok->next();
+                if (!tok)
+                    break;
+            }
         }
         // Freeing memory (not considered "using" the pointer if it was also allocated in this function)
         if (Token::Match(tok, "free|g_free|kfree|vfree ( %var% )") ||
diff --git a/test/testunusedvar.cpp b/test/testunusedvar.cpp
index 0f4f66a91..212727a4b 100644
--- a/test/testunusedvar.cpp
+++ b/test/testunusedvar.cpp
@@ -87,6 +87,7 @@ private:
         TEST_CASE(localvar39); // ticket #3454
         TEST_CASE(localvar40); // ticket #3473
         TEST_CASE(localvar41); // ticket #3481
+        TEST_CASE(localvar42); // ticket #3603
         TEST_CASE(localvaralias1);
         TEST_CASE(localvaralias2); // ticket #1637
         TEST_CASE(localvaralias3); // ticket #1639
@@ -1401,6 +1402,16 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void localvar42() {
+        // #3603 - false positive 'x is assigned a value that is never used'
+        functionVariableUsage("int f() {\n"
+                              "    int x = 1;\n"
+                              "    int y = FOO::VALUE * x;\n"
+                              "    return y;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void localvaralias1() {
         functionVariableUsage("void foo()\n"
                               "{\n"