Fixed #3672: bitwise and operator in if/while does no longer confuse setVarId code

Improvements to CheckUnusedVar:
- Improved handling of arrays of struct/class instances
- Differ between addressof and bitwise-and operator
- Made some members private to improve encapsulation
- Replaced some simple patterns by direct function calls
- Removed an unnecessary condition

lib/checkunusedvar.cpp

@@ -620,6 +620,8 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
                     break;
                 }
             }
+            if (i->isArray() && i->isClass()) // Array of class/struct members. Initialized by ctor.
+                variables.write(i->varId());
             if (i->isArray() && Token::Match(i->nameToken(), "%var% [ %var% ]")) // Array index variable read.
                 variables.read(i->nameToken()->tokAt(2)->varId());
 
@@ -706,7 +708,7 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             }
         }
 
-        else if (Token::Match(tok, "return|throw %var%")) {
+        else if (Token::Match(tok, "return|throw")) {
             for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
                 if (tok2->varId())
                     variables.readAll(tok2->varId());
@@ -838,7 +840,12 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             }
         }
 
-        else if (Token::Match(tok, ">>|& %var%"))
+        else if (Token::Match(tok, "& %var%")) {
+            if (tok->previous()->isName() || tok->previous()->isNumber()) { // bitop
+                variables.read(tok->next()->varId());
+            } else // addressof
+                variables.use(tok->next()->varId()); // use = read + write
+        } else if (Token::Match(tok, ">> %var%"))
             variables.use(tok->next()->varId()); // use = read + write
         else if (Token::Match(tok, "%var% >>|&") && Token::Match(tok->previous(), "[{};:]"))
             variables.read(tok->varId());
@@ -865,8 +872,8 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
         else if (Token::Match(tok, "%var% ."))
             variables.use(tok->varId());   // use = read + write
 
-        else if ((Token::Match(tok, "[(=&!]") || tok->isExtendedOp()) &&
-                 (Token::Match(tok->next(), "%var%") && !Token::Match(tok->next(), "true|false|new")) && tok->strAt(2) != "=")
+        else if (tok->isExtendedOp() &&
+                 Token::Match(tok->next(), "%var%") && !Token::Match(tok->next(), "true|false|new") && tok->strAt(2) != "=")
             variables.readAll(tok->next()->varId());
 
         else if (Token::Match(tok, "%var%") && (tok->next()->str() == ")" || tok->next()->isExtendedOp()))
@@ -994,9 +1001,9 @@ void CheckUnusedVar::checkStructMemberUsage()
 
         if (Token::Match(tok, "struct|union %type% {")) {
             structname.clear();
-            if (Token::simpleMatch(tok->previous(), "extern"))
+            if (tok->strAt(-1) == "extern")
                 continue;
-            if ((!tok->previous() || Token::simpleMatch(tok->previous(), ";")) && Token::Match(tok->linkAt(2), ("} ; " + tok->strAt(1) + " %var% ;").c_str()))
+            if ((!tok->previous() || tok->previous()->str() == ";") && Token::Match(tok->linkAt(2), ("} ; " + tok->strAt(1) + " %var% ;").c_str()))
                 continue;
 
             structname = tok->strAt(1);

lib/checkunusedvar.h

@@ -70,6 +70,7 @@ public:
     /** @brief %Check that all struct members are used */
     void checkStructMemberUsage();
 
+private:
     // Error messages..
     void unusedStructMemberError(const Token *tok, const std::string &structname, const std::string &varname);
     void unusedVariableError(const Token *tok, const std::string &varname);

lib/tokenize.cpp

@@ -2814,7 +2814,7 @@ void Tokenizer::setVarId()
         if (Token::Match(tok, "( %type% *|& %var% [),]") && !tok->next()->isStandardType()) {
             if (!Token::Match(tok->previous(), "%type%"))
                 continue;
-            if (tok->previous() && tok->previous()->str() == "return")
+            if (Token::Match(tok->previous(), "return|if|while"))
                 continue;
             if (tok->link() && !Token::Match(tok->link()->next(), "const| {") &&
                 (!tok->link()->next() || tok->link()->next()->str() != ":"))

test/testtokenize.cpp

@@ -206,6 +206,7 @@ private:
         TEST_CASE(varid40);   // ticket #3279
         TEST_CASE(varid41);   // ticket #3340 (varid for union type)
         TEST_CASE(varid42);   // ticket #3316 (varid for array)
+        TEST_CASE(varid43);
         TEST_CASE(varid44);
         TEST_CASE(varidFunctionCall1);
         TEST_CASE(varidFunctionCall2);
@@ -3248,6 +3249,13 @@ private:
                       tokenizeDebugListing(code));
     }
 
+    void varid43() {
+        const std::string code("int main(int flag) { if(a & flag) { return 1; } }");
+        ASSERT_EQUALS("\n\n##file 0\n"
+                      "1: int main ( int flag@1 ) { if ( a & flag@1 ) { return 1 ; } }\n",
+                      tokenizeDebugListing(code));
+    }
+
     void varid44() {
         const std::string code("class A:public B,public C,public D {};");
         ASSERT_EQUALS("\n\n##file 0\n"