Bool ~~ BooleanEnum returns true

[Leont]

The Problem

For any enum that contains a Boolean value, e.g. enum BooleanEnum (:!Lies, :Truth), matching a boolean against that enum's type object will return true even though the boolean is not an enum

Expected Behavior

True ~~ BooleanEnum returns False

Actual Behavior

True ~~ BooleanEnum returns True

Environment

Welcome to Rakudo(tm) v2020.12.
Implementing the Raku(tm) programming language v6.d.
Built on MoarVM version 2020.12.

[vrurg]

The observed behavior is correct. The point is:

say BooleanEnum.^mro; # ((Bool) (Bool) (Int) (Cool) (Any) (Mu))

The only thing which confuses me here is the first (Bool) because normally it should be the enum itself:

enum SS (:a(3e0), :b(4e0));
say SS.^mro; # ((SS) (Num) (Cool) (Any) (Mu))

But otherwise the pattern of enum having the base type of its values is followed as expected.

[Leont]

The observed behavior is correct. The point is:

say BooleanEnum.^mro; # ((Bool) (Bool) (Int) (Cool) (Any) (Mu))

I'm not sure what point you're trying to make here.

The only thing which confuses me here is the first (Bool) because normally it should be the enum itself:

enum SS (:a(3e0), :b(4e0));
say SS.^mro; # ((SS) (Num) (Cool) (Any) (Mu))

But otherwise the pattern of enum having the base type of its values is followed as expected.

Apparently:

raku -e 'enum Foo (:Truth); dd Foo.WHAT, Truth.WHAT'
Bool
Bool

Which would explain the observed behavior, but raises a bunch of new questions at the same time.

[jnthn]

An enumeration type is a subtype of the type of its values (which should all have a consistent type, otherwise it's an error).

[Leont]

An enumeration type is a subtype of the type of its values (which should all have a consistent type, otherwise it's an error).

I get that. I totally expect BooleanEnum ~~ Bool, but the other way around should be false. And it is false for all other types AFAICT.

[vrurg]

My apologies, there is actually a problem. Apparently, BooleanEnum must be a type on its own akin to SS from my example. Besides, SS behaves as expected:

say 3e0 ~~ SS; # False

The same should be expected for True ~~ BooleanEnum.

[jnthn]

but the other way around should be false

Goodness, I managed to do the same thinko as @vrurg. At least I'm in good company... :-)

[2colours]

Apparently, this issue has been fixed in the meantime:

https://gist.github.com/Whateverable/f0e879eb4cfc6ce67c9dbc144a1b1c41
https://gist.github.com/Whateverable/7759c03d6978abeff0fdc5dc3d152927
Bisects to this commit:
9f80771

@Leont Do you think this issue can be closed now?

[vrurg]

We need a test for this case first. Resolution of this issue was unintentional, no specific test has been done.