Partial fix for #13330 FN knownConditionTrueFalse with comma operator

lib/vf_settokenvalue.cpp

@@ -216,6 +216,25 @@ namespace ValueFlow
         return false;
     }
 
+    static bool isFunctionCall(const Token* tok, const Settings& settings)
+    {
+        if (!tok)
+            return false;
+        if (tok->str() == "{")
+            return true;
+        if (tok->str() == "(") {
+            if (tok->astOperand1() && tok->astOperand1()->isControlFlowKeyword())
+                return false;
+            if (Token::Match(tok->next(), "%name%") && !settings.library.isNotLibraryFunction(tok->next()))
+                return true;
+            if (Token::Match(tok->previous(), "%name%|>"))
+                return true;
+            if (Token::Match(tok->astOperand1(), "%name%|(|[|*|."))
+                return true;
+        }
+        return false;
+    }
+
     /** set ValueFlow value and perform calculations if possible */
     void setTokenValue(Token* tok,
                        Value value,
@@ -254,9 +273,7 @@ namespace ValueFlow
                 return !Token::simpleMatch(p, ",");
             });
             // Ensure that the comma isn't a function call
-            if (!callParent || (!Token::Match(callParent->previous(), "%name%|> (") && !Token::simpleMatch(callParent, "{") &&
-                                (!Token::Match(callParent, "( %name%") || settings.library.isNotLibraryFunction(callParent->next())) &&
-                                !(callParent->str() == "(" && Token::Match(callParent->astOperand1(), "%name%|(|[|*|.")))) {
+            if (!isFunctionCall(callParent, settings)) {
                 setTokenValue(parent, std::move(value), settings);
                 return;
             }

test/testcondition.cpp

@@ -5011,6 +5011,14 @@ class TestCondition : public TestFixture {
                       "[test.cpp:9:9]: (style) Condition '0b101010' is always true [knownConditionTrueFalse]\n"
                       "[test.cpp:10:9]: (style) Condition '!42' is always false [knownConditionTrueFalse]\n",
                       errout_str());
+
+        check("bool g(int = 1) __attribute__((pure));\n"
+              "void f() {\n"
+              "    int n = 0;\n"
+              "    if (g(), n) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4:12]: (style) Condition 'g(),n' is always false [knownConditionTrueFalse]\n",
+                      errout_str());
     }
 
     void alwaysTrueSymbolic()

test/testvalueflow.cpp

@@ -1887,6 +1887,16 @@ class TestValueFlow : public TestFixture {
                "}\n";
         values = tokenValues(code, ",");
         ASSERT_EQUALS(0U, values.size());
+
+        code = "void f() {\n"
+               "    int a = 4;\n"
+               "    if (g(), a) {}\n"
+               "}\n";
+        values = tokenValues(code, ",");
+        ASSERT_EQUALS(1U, values.size());
+        ASSERT(values.front().isKnown());
+        ASSERT(values.front().isIntValue());
+        ASSERT_EQUALS(4, values.front().intvalue);
     }
 
     void valueFlowErrorPath() {