At a quick glance, looks like a bug to me. Worth opening a ticket on
https://github.com/rakudo/rakudo
Best regards,
Vadim Belman
> On Jan 12, 2020, at 8:15 PM, Joseph Brenner <doom...@gmail.com> wrote:
>
> Moving the definition of the subset outside of the class
> covers for the weird behavior...
>
> my @allowed = << alpha beta gamma delta >>;
> my @default = << alpha >>;
> subset Allowed of Str where * eq any( @allowed );
>
> class HasSubset {
> has Allowed @.grk = @default;
> method echo_grk {
> say @!grk.join(" | ");
> }
> }
>
> my $obj = HasSubset.new();
> $obj.echo_grk();
>
> my $obj2 = HasSubset.new( grk => << alpha beta gamma >> );
> $obj2.echo_grk();
>
> my $obj3 = HasSubset.new( grk => << alpha beta rutabaga >> );
> $obj3.echo_grk();
> # value 'rutabaga' fails as expected:
> # Type check failed in assignment to @!grk; expected
> HasSubset::Allowed but got Str ("rutabaga")
>
>
> On 1/12/20, Joseph Brenner <doom...@gmail.com> wrote:
>> Here's a code snippet that tries to use a subset to constrain the
>> values of an object field (i.e. declared with has). As written, this
>> code works, but only when there's what looks like an irrelevant
>> experimental line in it (labeled "WEIRD ONE"), when that line is
>> commented out it throws an error...
>>
>> class HasSubset {
>> my @allowed = << alpha beta gamma delta >>;
>> my @default = << alpha >>;
>>
>> subset Allowed of Str where * eq any( @allowed );
>>
>> my Allowed $experiment = 'delta'; # WEIRD ONE this line is
>> *needed* to get the following to work...
>>
>> has Allowed @.greek = @default;
>>
>> method echo_greek {
>> say @!greek.join(" | ");
>> }
>> }
>>
>> my $obj = HasSubset.new();
>> $obj.echo_greek();
>>
>> # As written, prints the default: 'alpha'
>> # Without the WEIRD ONE line, you see errors like:
>> ## Type check failed in assignment to @!greek; expected
>> HasSubset::Allowed but got Str ("alpha")
>>
>
