Fixed cppcheck-opensource#7477 (False positive 'Assigned value is never used' in multithreaded context)

Author: danmar

lib/checkunusedvar.cpp

@@ -1070,6 +1070,8 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             variables.use(tok->next()->varId(), tok);   // use = read + write
         } else if (Token::Match(tok, "[(,] %var% [,)]") && tok->previous()->str() != "*") {
             variables.use(tok->next()->varId(), tok);   // use = read + write
+        } else if (Token::Match(tok, "[(,] & %var% [,)]")) {
+            variables.eraseAll(tok->tokAt(2)->varId());
         } else if (Token::Match(tok, "[(,] (") &&
                    Token::Match(tok->next()->link(), ") %var% [,)]")) {
             variables.use(tok->next()->link()->next()->varId(), tok);   // use = read + write
@@ -1083,6 +1085,8 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
         // function
         else if (Token::Match(tok, "%var% (")) {
             variables.read(tok->varId(), tok);
+        } else if (Token::Match(tok, "std :: ref ( %var% )")) {
+            variables.eraseAll(tok->tokAt(4)->varId());
         }
 
         else if (Token::Match(tok->previous(), "[{,] %var% [,}]")) {

test/testunusedvar.cpp

@@ -161,6 +161,7 @@ class TestUnusedVar : public TestFixture {
         TEST_CASE(localvarAssignInWhile);
         TEST_CASE(localvarTemplate); // #4955 - variable is used as template parameter
         TEST_CASE(localvarFuncPtr); // #7194
+        TEST_CASE(localvarAddr); // #7477
 
         TEST_CASE(localvarCppInitialization);
         TEST_CASE(localvarCpp11Initialization);
@@ -3971,6 +3972,22 @@ class TestUnusedVar : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void localvarAddr() { // #7747
+        functionVariableUsage("void f() {\n"
+                              "  int x = 0;\n"
+                              "  dostuff(&x);\n"
+                              "  x = 1;\n"
+                              "}");
+        ASSERT_EQUALS("", errout.str());
+
+        functionVariableUsage("void f() {\n"
+                              "  int x = 0;\n"
+                              "  dostuff(std::ref(x));\n"
+                              "  x = 1;\n"
+                              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void chainedAssignment() {
         // #5466
         functionVariableUsage("void NotUsed(double* pdD, int n) {\n"