gistfile1.txt

use v6;
use Slang::Tuxic;

class C {
    method foo (Any :$in) {
        my IO $io-in;
        # in
        #   parse
        #     "file.csv"                    Str
        #     $io                           IO::Handle
        #     \"str,ing"                    Capture
        #   generate
        #     [[1,2],[3,4]]         AoA     Array
        #     [{1,2},{3,4}]         AoH     Array
        #     [1=>2,3=>4]           AoP     Array
        #     sub { ... }                   Sub
        $in.WHAT.say;
        $in.perl.say;
        given $in.WHAT {
            when Str {
                $io-in = open $in, :r, chomp => False;
                };
            when Array {
                my @in = $in;
                @in[0].WHAT.say;
                };
            when Routine {
                };
            default {
                die "5000: error";
                };
            }
        }
    }

C.new.foo(in => "test.csv");


Without Slang::Tuxic, PASS
With Slang::Tuxic:

===SORRY!=== Error while compiling T.pl
Missing block
at T.pl:33
------>             }⏏<EOL>
    expecting any of:
        parameterized block