From zefram@fysh.org

$ ./perl6 -e 'my $a = 0.99999999999999999999999; say $a; say $a.WHICH; say $a > 1'
1.000000000000000083886070
Rat|99999999999999999999999/99999999999999991611392
True

The Rat that is generated from this literal is a pretty poor approximation
of the value that it appears to represent. 1/1 would have been a
better approximation, if it's not acceptable to handle it exactly.
Adding more 9s to the literal produces a variety of approximated Rats,
of varying quality, some above 1 and some below.

-zefram

From @AlexDaniel

I think this is already fixed in rakudo/rakudo@f6e25b5

¦f6e25b54ea18ba7bd7d78^​:
1.000000000000000083886070
Rat|99999999999999999999999/99999999999999991611392
True

¦f6e25b54ea18ba7bd7d78​:
1
Rat|99999999999999999999999/100000000000000000000000
False

Maybe tests this were already added in https://rt-archive.perl.org/perl6/Ticket/Display.html?id=130845 , but I'll mark it as TESTNEEDED just in case.

On 2015-09-18 12​:45​:27, zefram@​fysh.org wrote​:

$ ./perl6 -e 'my $a = 0.99999999999999999999999; say $a; say $a.WHICH;
say $a > 1'
1.000000000000000083886070
Rat|99999999999999999999999/99999999999999991611392
True

The Rat that is generated from this literal is a pretty poor
approximation
of the value that it appears to represent. 1/1 would have been a
better approximation, if it's not acceptable to handle it exactly.
Adding more 9s to the literal produces a variety of approximated Rats,
of varying quality, some above 1 and some below.

-zefram

The RT System itself - Status changed from 'new' to 'open'

From @moritz

Added another test here​: Raku/roast@a0b678199c

@moritz - Status changed from 'open' to 'resolved'