stringbuilder gcc 11 error: 'void* memcpy(void*, const void*, size_t)' copying an object of non-trivial type 'class QChar' from an array of 'const char16_t' [-Werror=class-memaccess]

[4158/11242] Building CXX object qtdeclarative/src/qml/CMakeFiles/Qml.dir/jsruntime/qv4qobjectwrapper.cpp.o
FAILED: qtdeclarative/src/qml/CMakeFiles/Qml.dir/jsruntime/qv4qobjectwrapper.cpp.o 
/usr/lib/ccache/bin/c++ -DBUILDING_QT__ -DENABLE_ASSEMBLER_WX_EXCLUSIVE=1 -DENABLE_DFG_JIT=0 -DENABLE_DFG_JIT_UTILITY_METHODS=1 -DENABLE_JIT_CONSTANT_BLINDING=0 -DENABLE_LLINT=0 -DJS_EXPORT_PRIVATE="" -DQT_ASCII_CAST_WARNINGS -DQT_BUILDING_QT -DQT_BUILD_QML_LIB -DQT_CORE_LIB -DQT_DEPRECATED_WARNINGS -DQT_DEPRECATED_WARNINGS_SINCE=0x060000 -DQT_DISABLE_DEPRECATED_BEFORE=0x050000 -DQT_MOC_COMPAT -DQT_NETWORK_LIB -DQT_NO_CAST_TO_ASCII -DQT_NO_EXCEPTIONS -DQT_NO_FOREACH -DQT_NO_INTEGER_EVENT_COORDINATES -DQT_NO_URL_CAST_FROM_STRING -DQT_USE_QSTRINGBUILDER -DQml_EXPORTS -DWTFInvokeCrashHook=qmlWTFInvokeCrashHook -DWTFReportAssertionFailure=qmlWTFReportAssertionFailure -DWTFReportAssertionFailureWithMessage=qmlWTFReportAssertionFailureWithMessage -DWTFReportBacktrace=qmlWTFReportBacktrace -DWTF_EXPORT_PRIVATE="" -DWTF_USE_UDIS86=0 -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/Qml_autogen/include -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtQml -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/compiler -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/jsruntime -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/memory -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/qmldirparser -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/assembler -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/disassembler -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/disassembler/udis86 -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/jit -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/runtime -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/stubs -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/stubs/runtime -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/stubs/wtf -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/../3rdparty/masm/wtf -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/.generated -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/compiler -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/debugger -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/memory -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/qmldirparser -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtQml/6.2.0 -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtQml/6.2.0/QtQml -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/src/corelib -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/6.2.0 -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/6.2.0/QtCore -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/mkspecs/linux-g++ -I/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtNetwork -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/.generated/debug -I/home/rutledge/dev/qt-stabilizing-dbg/qtdeclarative/src/qml/jit -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jit -I/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/animations -g -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -Wall -Wextra -fno-exceptions -fPIC -Werror -Wno-error=cpp -Wno-error=deprecated-declarations -Wno-error=strict-overflow -Wno-error=implicit-fallthrough -Wno-error=deprecated-copy -Wno-error=redundant-move -Wno-error=init-list-lifetime -Wno-error=format-overflow -Wno-error=stringop-overflow -Wno-error=deprecated-enum-enum-conversion -Wno-error=deprecated-enum-float-conversion -no-integrated-cpp -Wno-implicit-fallthrough -Wsuggest-override -std=c++17 -MD -MT qtdeclarative/src/qml/CMakeFiles/Qml.dir/jsruntime/qv4qobjectwrapper.cpp.o -MF qtdeclarative/src/qml/CMakeFiles/Qml.dir/jsruntime/qv4qobjectwrapper.cpp.o.d -o qtdeclarative/src/qml/CMakeFiles/Qml.dir/jsruntime/qv4qobjectwrapper.cpp.o -c /home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper.cpp
In file included from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qstringbuilder.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qstring.h:1583,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qstring.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/tools/qhashfunctions.h:44,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qhashfunctions.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/tools/qvarlengtharray.h:47,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qvarlengtharray.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/kernel/qmetatype.h:49,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qmetatype.h:1,
                 from /home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper_p.h:55,
                 from /home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper.cpp:40:
/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qstringbuilder.h: In instantiation of 'static void QConcatenable<const char16_t [N]>::appendTo(const char16_t*, QChar*&) [with long long int N = 6]':
/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qstringbuilder.h:402:35:   required from 'static void QConcatenable<QStringBuilder< <template-parameter-1-1>, <template-parameter-1-2> > >::appendTo(const type&, T*&) [with T = QChar; A = char16_t [6]; B = QString; QConcatenable<QStringBuilder< <template-parameter-1-1>, <template-parameter-1-2> > >::type = QStringBuilder<char16_t [6], QString>]'
/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qstringbuilder.h:460:52:   required from 'QString& operator+=(QString&, const QStringBuilder<A, B>&) [with A = char16_t [6]; B = QString]'
/home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper.cpp:1749:75:   required from here
/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qstringbuilder.h:338:15: error: 'void* memcpy(void*, const void*, size_t)' copying an object of non-trivial type 'class QChar' from an array of 'const char16_t' [-Werror=class-memaccess]
  338 |         memcpy(out, a, (N - 1) * sizeof(char16_t));
      |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qchar.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qstring.h:50,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qstring.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/tools/qhashfunctions.h:44,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qhashfunctions.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/tools/qvarlengtharray.h:47,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qvarlengtharray.h:1,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/kernel/qmetatype.h:49,
                 from /home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/qmetatype.h:1,
                 from /home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper_p.h:55,
                 from /home/rutledge/dev/qt-stabilizing/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper.cpp:40:
/home/rutledge/dev/qt-stabilizing-dbg/qtbase/include/QtCore/../../../../qt-stabilizing/qtbase/src/corelib/text/qchar.h:84:46: note: 'class QChar' declared here
   84 | class Q_CORE_EXPORT QChar {
      |                                              ^    
cc1plus: all warnings being treated as errors
[4191/11242] Building CXX object qtdeclarative/src/qml/CMakeFiles/Qml.dir/qml/qqmlpropertyvalidator.cpp.o
ninja: build stopped: subcommand failed.

    if (best && best->isValid()) {
        return best;
    } else {
        QString error = QLatin1String("Unable to determine callable overload.  Candidates are:");
        for (int i = 0; i < methodCount; ++i) {
            for (int i = 0; i < methodCount; ++i) {
                const QQmlPropertyData &candidate = methods[i];
                const QMetaMethod m = candidate.isConstructor()
                                      ? object.metaObject()->constructor(candidate.coreIndex())
                                      : object.metaObject()->method(candidate.coreIndex());
                error += u"\n    " + QString::fromUtf8(m.methodSignature()); // <--- from here
            }
        }

        engine->throwError(error);
        return nullptr;
    }

template <qsizetype N> struct QConcatenable<const char16_t[N]> : private QAbstractConcatenable
{
    using type = const char16_t[N];
    using ConvertTo = QString;
    enum { ExactSize = true };
    static qsizetype size(const char16_t[N]) { return N - 1; }
    static void appendTo(const char16_t a[N], QChar *&out)
    {
        memcpy(out, a, (N - 1) * sizeof(char16_t)); // <--- the memcpy
        out += N - 1;
    }
};