Fix #14060 FN containerOutOfBounds with multi-parameter std::stack::emplace() (regression) (#7726)

Author: chrchr-github

lib/vf_analyzers.cpp

@@ -1489,7 +1489,12 @@ struct ContainerExpressionAnalyzer : ExpressionAnalyzer {
             const Library::Container::Action action = container->getAction(tok->astParent()->strAt(1));
             if (action == Library::Container::Action::PUSH || action == Library::Container::Action::POP || action == Library::Container::Action::APPEND) { // TODO: handle more actions?
                 std::vector<const Token*> args = getArguments(tok->tokAt(3));
-                if (args.size() < 2 || action == Library::Container::Action::APPEND)
+                bool isVariadic = false;
+                if (const Library::Function* libFunc = settings.library.getFunction(tok->tokAt(2))) {
+                    const auto& argChecks = libFunc->argumentChecks;
+                    isVariadic = argChecks.find(-1) != argChecks.end() && argChecks.at(-1).variadic;
+                }
+                if (args.size() < 2 || action == Library::Container::Action::APPEND || isVariadic)
                     return Action::Read | Action::Write | Action::Incremental;
             }
         }

test/testvalueflow.cpp

@@ -7172,6 +7172,15 @@ class TestValueFlow : public TestFixture {
                "}\n";
         ASSERT_EQUALS(true, tokenValues(code, "a . size", ValueFlow::Value::ValueType::CONTAINER_SIZE).empty());
 
+        code = "void f() {\n" // #14060
+               "    std::stack<std::pair<int, int>> s;\n"
+               "    s.emplace(0, 0);\n"
+               "    s.pop();\n"
+               "    bool x = s.empty();\n"
+               "    return x;\n"
+               "}\n";
+        ASSERT_EQUALS(true, testValueOfXKnown(code, 6U, 1));
+
         code = "std::vector<int> g();\n"
                "std::vector<int> f() {\n"
                "    std::vector<int> v = g();\n"