When using the Types::Standard's InstanceOf in combination with Function::Parameters, the code using plain InstanceOf doesn't compile:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

{   package My;
    sub new { bless {}, shift }
}

use Function::Parameters;
use Types::Standard qw( InstanceOf );

fun validate(InstanceOf['My'] $m) {  # <- Fails :-(
    say "object:", $m;
}

my $m = 'My'->new;
validate($m);
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The exact error message is

In fun validate: missing type name after '[' at 1.pl line 13.
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It seems both the modules extend the parser somehow and they step on each other's toes.

Fortunately, it's pretty easy to fix that: you can prevent Function::Parameters from interpreting the InstanceOf before Types::Standard handles it by enclosing it into parentheses:

fun validate((InstanceOf['My']) $m) {  # <- Works :-)
#            ~                ~
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