ICON qmake variable doesn't work on Windows

I have the following project file

# FormTest01.pro
QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = FormTest01
TEMPLATE = app
VERSION = 1.0.3
ICON = FormTest.ico

SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

The icon file should be added in the FormTest01_resource.rc generated file to display accordingly the application icon with the following line:

IDI_ICON1 ICON DISCARDABLE "FormTest.ico"

I know that I can use RC_FILE qmake variable but it would cancel the automatic FormTest01_resource.rc* generation that contains information about the version.

It works if I add it manually between qmake and make.