Possible compiler/lib bug: gfortran intrinsic function loc() unrecognized?

Possible compiler/lib bug: gfortran intrinsic function loc() unrecognized?

[Bo-Hai Li]

Dear committee,

     I was trying to monitor my fortran arrays by their address. I typed

         "print * , loc(real_array_to_monitor)"

in my source1.F90 source file and compiled the project with Makefile rules

         "gfortran -c -o source1.o -std=f2008 -cpp -O3 blablabla".

     Then something WIERD happened, the compiler gives an error reads

         "Function ‘loc’ at (1) has no IMPLICIT type"

     It just does not make any sense. loc() is an intrinsic function of 
gfortran that I read from the newest manual

https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gfortran/LOC.html#LOC

and there is no reason the compiler does not recognize it.

     I am running gfortran 9.3.0 on Ubuntu 20.04 and I did not find any 
update about loc() in the update WhatsNew. I failed to get any useful 
information on internet because every website lead to the official doc 
where no problem about loc() is mentioned.

     Is there any change of function loc() that has not been written 
into the doc? Why is an intrinsic function unrecognized by the compiler? 
Wish to hear from you. Thank you!

-- 
Best regards,
Bo-Hai Li
Kavli Institute for Theoretical Science,
University of Chinese Academy of Science
e-mail: paperonprl@gmail.com