"F90-F-0000-Internal compiler error" with the -x option

[zaikunzhang]

I am using Flang Binary Release 2019-03-29 from https://github.com/flang-compiler/flang/releases/tag/flang_20190329

Consider the following do-nothing code named test.f90:

! test.f90
program test                                                                                                                                                                                                       
end program test         

If I compile it with

flang test.f90

everything works. However, If I compile it with

flang -x f95 - < test.f90 

then I receive

F90-F-0000-Internal compiler error. Unknown command line argument:        0 
F90/x86-64 Linux Flang - 1.5 2017-05-01: compilation aborted

Does it seem to be a bug?

Thank you very much for your attention.