$ perl -E'
   sub IO::Handle::myprint { say "..."; }
   sub myprint { myprint STDOUT @_ }

   myprint STDOUT "foo";
   myprint "foo";

   eval q{ myprint(STDOUT "foo");      1 } or warn $@;
   eval q{ myprint(\*STDOUT "foo");    1 } or warn $@;
   eval q{ myprint { STDOUT } "foo";   1 } or warn $@;
   eval q{ myprint { \*STDOUT } "foo"; 1 } or warn $@;
'
syntax error at (eval 1) line 1, near "STDOUT "foo""
syntax error at (eval 2) line 1, near "*STDOUT "foo""
syntax error at (eval 3) line 1, near "} "foo""
syntax error at (eval 4) line 1, near "} "foo""