How to find package functions that are shadowed?

I'm missing something.

It is possible to have several package functions with identical fully qualified names, e.g. p1.test, on the search path. The statement

which( 'p1.test', '-all' )

should be the way to discover shadowed package functions. However, I fail to make that work. This script below illustrates my problem. which() finds only one of the two p1.test

%%
addpath( cd )
mkdir( cd, '+p1' );      
mkdir( fullfile(cd,'f1'), '+p1' );
addpath(fullfile('.','f1'));
str2txt( fullfile(cd,'+p1','test.m'), '% test' ); 
str2txt( fullfile(cd,'f1','+p1','test.m'), '% test' );
%%
cd ..
which( 'p1.test', '-all' )

/users/mss.system.iBN0QN/f1/+p1/test.m  % static method or package function

%%
function    str2txt( ffs, str )
fid = fopen( ffs, 'wt' );
fprintf( fid, '%s', str );
fclose( fid );
end