ValueFlow: Improved bailout when variable is reassigned

lib/token.cpp

@@ -84,17 +84,8 @@ void Token::update_property_info()
             _type = eString;
         else if (_str.length() > 1 && _str[0] == '\'' && _str[_str.length()-1] == '\'')
             _type = eChar;
-        else if (_str == "="   ||
+        else if (_str == "="   || _str == "<<=" || _str == ">>=" ||
-                 _str == "+="  ||
+                 (_str.size() == 2U && _str[1] == '=' && std::strchr("+-*/%&^|",_str[0])))
-                 _str == "-="  ||
-                 _str == "*="  ||
-                 _str == "/="  ||
-                 _str == "%="  ||
-                 _str == "&="  ||
-                 _str == "^="  ||
-                 _str == "|="  ||
-                 _str == "<<=" ||
-                 _str == ">>=")
             _type = eAssignmentOp;
         else if (_str.size() == 1 && _str.find_first_of(",[]()?:") != std::string::npos)
             _type = eExtendedOp;

lib/tokenlist.cpp

@@ -417,14 +417,6 @@ static void compileUnaryOp(Token *&tok, void (*f)(Token *&, std::stack<Token*> &
     op.push(unaryop);
 }
 
-static bool isAssignment(const Token *tok)
-{
-    return (tok->str() == "=" ||
-            tok->str() == "<<=" ||
-            tok->str() == ">>=" ||
-            (tok->str().size() == 2U && tok->str()[1] == '=' && std::strchr("+-*/%&|^",tok->str()[0])));
-}
-
 static void compileBinOp(Token *&tok, void (*f)(Token *&, std::stack<Token*> &, unsigned int depth), std::stack<Token*> &op, unsigned int depth)
 {
     Token *binop = tok;
@@ -433,7 +425,7 @@ static void compileBinOp(Token *&tok, void (*f)(Token *&, std::stack<Token*> &,
         f(tok,op, depth);
 
     // Assignment operators are executed in right-to-left order
-    if (tok && isAssignment(binop) && isAssignment(tok))
+    if (binop->isAssignmentOp() && tok && tok->isAssignmentOp())
         compileBinOp(tok,f,op,depth);
 
     // TODO: Should we check if op is empty.
@@ -726,7 +718,7 @@ static void compileAssign(Token *&tok, std::stack<Token*> &op, unsigned int dept
 {
     compileTernaryOp(tok,op, depth);
     while (tok) {
-        if (isAssignment(tok)) {
+        if (tok->isAssignmentOp()) {
             compileBinOp(tok, compileTernaryOp, op, depth);
         } else break;
     }

lib/valueflow.cpp

@@ -678,7 +678,7 @@ static void valueFlowAfterAssign(TokenList *tokenlist, ErrorLogger *errorLogger,
 
             if (tok2->varId() == varid) {
                 // bailout: assignment
-                if (Token::Match(tok2->previous(), "!!* %var% =")) {
+                if (Token::Match(tok2->previous(), "!!* %var% %op%") && tok2->next()->isAssignmentOp()) {
                     if (settings->debugwarnings)
                         bailout(tokenlist, errorLogger, tok2, "assignment of " + tok2->str());
                     break;

test/testvalueflow.cpp

@@ -507,6 +507,13 @@ private:
                "}";
         ASSERT_EQUALS(false, testValueOfX(code, 4U, 9));
 
+        code = "void f() {\n"
+               "    int x = 0;\n"
+               "    y = x += z;\n"
+               "    return x;\n"
+               "}";
+        ASSERT_EQUALS(false, testValueOfX(code, 4U, 0));
+
         code = "void f() {\n"
                "    static int x = 2;\n"
                "    x++;\n"