Failure to link code generated by ICC 16 against MSVC 2013's QtCore

When you use Qt compiled with MSVC 2013 and try to link certain code using QString::toLower, QString::toUpper, QString::trimmed, the link will fail with error:

error LNK2001: unresolved external symbol "__declspec(dllimport) public: ?? :: ?? ::XZ::V1" (__imp_?toUpper@QString@@QEHAA?AV1@XZ)

If you pass the decorated name to MSVC 2015's undname.exe tool, it prints:

Undecoration of :- "?toUpper@QString@@QEHAA?AV1@XZ"
is :- "public: class QString __cdecl QString::toUpper(void) __ptr64&& "

The reason for the incompatibility is that ICC 16 does know about ref-qualified member functions and tries to call them in the DLL (see the "dllimport" part).