Missing return value from do when calling resume and CATCH is the last statement in a block

[hakonhagland]

The following code prints got value: (Any) whether an exception occurred or not:

use v6;

my $value = do {
    my $result = might-throw();
    CATCH {
        default {
            say "Caught exception: ", .^name;
            .resume;
        }
    }
    #my $result = might-throw(); # <-- It works if I move the call to might-throw()
                                 #     after the CATCH { ... }
};

say "got value: ", $value;

sub might-throw() {
    my $var = <0 1>.pick;
    if $var == 0 {
        die "Zero is not good!";
        -1;
    }
    else {
        1;
    }
}

It could be argued that the presence of the CATCH block should not have an effect on what is considered to be the last statement in the do block and hence what becomes the return value of the do block.

This behavior was confirmed by moving the call to migh-throw() after the CATCH { ... } as indicated with the comment in the code above. In this case the program prints got value: -1 or got value: 1 depending on whether an exception occurred or not, as would be expected for a normal do block.

Environment

• Operating system: Ubuntu 18.04
• Compiler version (perl6 -v): Rakudo version 2018.04.1 built on MoarVM version 2018.04.1