qdoc fails to link to qFuzzyIsNull

The following warning is raised by qdoc:

qt.qdoc: Parse source files for "QtTestLib"
qt.qdoc: Source files parsed for "QtTestLib"
.../qt/dev/qtbase/src/testlib/qtestcase.qdoc:103: (qdoc) warning: Can't link to 'qFuzzyIsNull()'
qt.qdoc: End qdoc for QtTestLib in dual process mode: generate phase.

even though both double and float overloads of qFuzzyIsNull() are documented in qglobal.cpp.

The same text also links to qFuzzyCompare, which also has two overload, is also constexpr and [[nodiscard]], and in the same qglobal.cpp area. So... no idea what's going on.