Improve fix for #9570: check if ternary operator is used in assignment to reference (#3614)

Author: chrchr-github

lib/astutils.cpp

@@ -1036,9 +1036,6 @@ static bool compareKnownValue(const Token * const tok1, const Token * const tok2
 {
     static const auto isKnownFn = std::mem_fn(&ValueFlow::Value::isKnown);
 
-    if ((tok1->variable() && tok1->variable()->isStatic()) || (tok2->variable() && tok2->variable()->isStatic()))
-        return false;
-
     const auto v1 = std::find_if(tok1->values().begin(), tok1->values().end(), isKnownFn);
     if (v1 == tok1->values().end()) {
         return false;
@@ -2114,6 +2111,10 @@ bool isVariableChanged(const Token *tok, int indirect, const Settings *settings,
 {
     if (!tok)
         return false;
+
+    if (indirect == 0 && isConstVarExpression(tok))
+        return false;
+
     const Token *tok2 = tok;
     int derefs = 0;
     while (Token::simpleMatch(tok2->astParent(), "*") ||
@@ -2582,6 +2583,8 @@ bool isConstVarExpression(const Token *tok, const char* skipMatch)
 {
     if (!tok)
         return false;
+    if (tok->str() == "?" && tok->astOperand2() && tok->astOperand2()->str() == ":") // ternary operator
+        return isConstVarExpression(tok->astOperand2()->astOperand1()) && isConstVarExpression(tok->astOperand2()->astOperand2()); // left and right of ":"
     if (skipMatch && Token::Match(tok, skipMatch))
         return false;
     if (Token::simpleMatch(tok->previous(), "sizeof ("))

lib/checkother.cpp

@@ -2293,7 +2293,7 @@ void CheckOther::checkDuplicateExpression()
                     }
                 }
             } else if (styleEnabled && tok->astOperand1() && tok->astOperand2() && tok->str() == ":" && tok->astParent() && tok->astParent()->str() == "?") {
-                if (!tok->astOperand1()->values().empty() && !tok->astOperand2()->values().empty() && isEqualKnownValue(tok->astOperand1(), tok->astOperand2()))
+                if (!isVariableChanged(tok->astParent(), /*indirect*/ 0, mSettings, mTokenizer->isCPP()) && !tok->astOperand1()->values().empty() && !tok->astOperand2()->values().empty() && isEqualKnownValue(tok->astOperand1(), tok->astOperand2()))
                     duplicateValueTernaryError(tok);
                 else if (isSameExpression(mTokenizer->isCPP(), true, tok->astOperand1(), tok->astOperand2(), mSettings->library, false, true, &errorPath))
                     duplicateExpressionTernaryError(tok, errorPath);