Fixed #4155 (false positive: Variable is assigned a value that is never used (inside BOOST_FOREACH loop))

lib/checkunusedvar.cpp

@@ -746,6 +746,14 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             break;
         }
 
+        if (Token::Match(tok,"%var% (") && Token::simpleMatch(tok->linkAt(1),") {") && !Token::Match(tok, "for|while|if|catch")) {
+            const Token * const endTok = tok->linkAt(1)->linkAt(1);
+            for (const Token *tok2 = endTok->link(); tok2 && tok2 != endTok; tok2 = tok2->next()) {
+                if (tok2->varId())
+                    variables.erase(tok2->varId());
+            }
+        }
+
         if (Token::Match(tok->previous(), "[;{}]")) {
             for (const Token* tok2 = tok->next(); tok2; tok2 = tok2->next()) {
                 if (tok2->varId()) {

test/testunusedvar.cpp

@@ -135,6 +135,7 @@ private:
         TEST_CASE(localvarIfElse);      // return tmp1 ? tmp2 : tmp3;
         TEST_CASE(localvarOpAssign);    // a |= b;
         TEST_CASE(localvarFor);         // for ( ; var; )
+        TEST_CASE(localvarForEach);     // BOOST_FOREACH, hlist_for_each, etc
         TEST_CASE(localvarShift1);      // 1 >> var
         TEST_CASE(localvarShift2);      // x = x >> 1
         TEST_CASE(localvarShift3);      // x << y
@@ -2948,6 +2949,18 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void localvarForEach() {
+        functionVariableUsage("void foo() {\n"
+                              "    int i = -1;\n"
+                              "    int a[] = {1,2,3};\n"
+                              "    FOREACH_X (int x, a) {\n"
+                              "        if (i==x) return x;\n"
+                              "        i = x;\n"
+                              "    }\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void localvarShift1() {
         functionVariableUsage("int foo()\n"
                               "{\n"