Fix 13738: Crash in valueFlowTypeTraits (danmar#7411)

Author: pfultz2

lib/valueflow.cpp

@@ -756,7 +756,12 @@ static void valueFlowTypeTraits(TokenList& tokenlist, const Settings& settings)
             continue;
         if (eval.count(traitName) == 0)
             continue;
-        ValueFlow::Value value = eval[traitName](evaluateTemplateArgs(templateTok->next()));
+        auto args = evaluateTemplateArgs(templateTok->next());
+        if (std::any_of(args.begin(), args.end(), [](const std::vector<const Token*>& arg) {
+            return arg.empty();
+        }))
+            continue;
+        ValueFlow::Value value = eval[traitName](std::move(args));
         if (value.isUninitValue())
             continue;
         value.setKnown();

test/testvalueflow.cpp

@@ -7894,6 +7894,11 @@ class TestValueFlow : public TestFixture {
                "    } while (true);\n"
                "}\n";
         (void)valueOfTok(code, "0");
+
+        code = "bool f() {\n"
+               "    return (!std::is_reference<decltype(a)>::value);\n"
+               "}\n";
+        (void)valueOfTok(code, "0");
     }
 
     void valueFlowHang() {