qmake -query

QT_SYSROOT:
QT_INSTALL_PREFIX:/..
QT_INSTALL_ARCHDATA:/..
QT_INSTALL_DATA:/..
QT_INSTALL_DOCS:/../doc
QT_INSTALL_HEADERS:/../include
QT_INSTALL_LIBS:/../lib
QT_INSTALL_LIBEXECS:/../bin
QT_INSTALL_BINS:/../bin
QT_INSTALL_TESTS:/../tests
QT_INSTALL_PLUGINS:/../plugins
QT_INSTALL_IMPORTS:/../imports
QT_INSTALL_QML:/../qml
QT_INSTALL_TRANSLATIONS:/../translations
QT_INSTALL_CONFIGURATION:
QT_INSTALL_EXAMPLES:/../examples
QT_INSTALL_DEMOS:/../examples
QT_HOST_PREFIX:/..
QT_HOST_DATA:/..
QT_HOST_BINS:/../bin
QT_HOST_LIBS:/../lib
QMAKE_SPEC:win32-msvc
QMAKE_XSPEC:win32-msvc
QMAKE_VERSION:3.1
QT_VERSION:5.14.1

qmake -tp vc -Wall -r xyz.pro

ASSERT: "fileName.isEmpty() || isAbsolutePath(fileName)" in file C:\Users\qt\work\qt\qtbase\qmake\library\ioutils.cpp, line 54

No MSVC solution file (sln) is generated.

Same project was working fine in 5.14.0