From b9b5734559774d7fe571b94fda7896e4806707f4 Mon Sep 17 00:00:00 2001
From: Mate Barany <mate.barany@qt.io>
Date: Mon, 20 Jun 2022 14:26:38 +0200
Subject: [PATCH] Disable useless-cast warning for moc generated code

The useless-cast gcc warning is disabled in the files generated by
the moc. A typical warning is like

using_t = void(Counter::*)(int );
if (*reinterpret_cast<_t*>(_a[1]) ==
    static_cast<_t>(&Counter::valueChanged)) {
        *result = 0;
         return;
    }

Removing the static cast results in a compilation error
"address of overloaded function with no contextual type-of
information" in moc_myobject.cpp files.

Checking whether we have an overload set or a single function
might be too much effort for too little benefit and may not worth
it.

Fixes: QTBUG-71938
Change-Id: I6f67e163a3493b51fb95f54218ce6bf9a302f824
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
---
 src/tools/moc/moc.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/tools/moc/moc.cpp b/src/tools/moc/moc.cpp
index 550c1ac422..dc8fcbf8db 100644
--- a/src/tools/moc/moc.cpp
+++ b/src/tools/moc/moc.cpp
@@ -1107,6 +1107,7 @@ void Moc::generate(FILE *out, FILE *jsonOutput)
     fprintf(out, "QT_BEGIN_MOC_NAMESPACE\n");
     fprintf(out, "QT_WARNING_PUSH\n");
     fprintf(out, "QT_WARNING_DISABLE_DEPRECATED\n");
+    fprintf(out, "QT_WARNING_DISABLE_GCC(\"-Wuseless-cast\")\n");
 
     fputs("", out);
     for (i = 0; i < classList.size(); ++i) {