Extend the reserved keywords for Qt projects with the following words:

 - signals (builtin Qt macro)
 - slots (builtin Qt macro)
 - NULL
 - valid (generated classes has an isValid method)
 - set (generated classes has an isSet method)

Fixes #17487

Author: martonmiklos

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCppCodegen.java

@@ -112,6 +112,7 @@ public AbstractCppCodegen() {
                         "noexcept",
                         "not",
                         "not_eq",
+                        "NULL",
                         "nullptr",
                         "operator",
                         "or",

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQtAbstractCodegen.java

@@ -129,6 +129,9 @@ public CppQtAbstractCodegen() {
         systemIncludes.add("QDate");
         systemIncludes.add("QDateTime");
         systemIncludes.add("QByteArray");
+
+        reservedWords.add("signals");
+        reservedWords.add("slots");
     }
 
     @Override

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQtClientCodegen.java

@@ -120,6 +120,9 @@ public CppQtClientCodegen() {
         typeMapping.put("AnyType", "QJsonValue");
         importMapping.put(PREFIX + "HttpFileElement", "#include \"" + PREFIX + "HttpFileElement.h\"");
         importMapping.put("QJsonValue", "#include <QJsonValue>");
+
+        reservedWords.add("valid");
+        reservedWords.add("set");
     }
 
     @Override