qmltc: fix GCC13 warnings "class X is implicitly friend with itself"

This happens because the generated code contains

    class X {
        ~~~~
    private:
        friend class X; // warning here
    };

Says GCC13 (e.g.):

    tests/auto/qml/qmltc/QmltcTests/.qmltc/qmltc_test_module/inlinecomponents.h:421:18: warning: class ‘QmltcTests::inlineComponents_IC0’ is implicitly friends with itself
      421 |     friend class inlineComponents_IC0;
          |                  ^~~~~~~~~~~~~~~~~~~~

It seems the intended check for documentRoot doesn't work in all
cases, so do the check on the class-name level.

There appears to be no -W flag to control this warning, therefore no
apparent way to suppress it, so we need to fix it.

Amends either b89a92053e1a4565d37f75831db1c6c90c21bce6 or
0990b892cab819f210120f8a9f9ca48522bde412. I didn't dig into it
further.

Pick-to: 6.6 6.5
Change-Id: I3fe653a398ea5b7a3e045fd3ea8dfb5d5c0f2e5c
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 2 insertions, 1 deletions

diff --git a/tools/qmltc/qmltccompiler.cpp b/tools/qmltc/qmltccompiler.cpp
index a623a683e6..34077a29d8 100644
--- a/tools/qmltc/qmltccompiler.cpp
+++ b/tools/qmltc/qmltccompiler.cpp
@@ -189,7 +189,8 @@ void QmltcCompiler::compileType(
         // make document root a friend to allow it to access init and endInit
         const QString rootInternalName =
                 m_visitor->inlineComponent(type->enclosingInlineComponentName())->internalName();
-        current.otherCode << u"friend class %1;"_s.arg(rootInternalName);
+        if (rootInternalName != current.cppType) // avoid GCC13 warning on self-befriending
+            current.otherCode << "friend class %1;"_L1.arg(rootInternalName);
     }
     if (documentRoot || inlineComponent) {
         auto name = type->inlineComponentName()