From @masak

<colomon> m​: my %b := BagHash.new(); %b.classify-list( {.comb}, 20..40
); say %b.perl
<camelia> rakudo-moar a46b09​: OUTPUT«postcircumfix​:<{ }> not defined
for type Int [...]
<colomon> masak​: ^^
* masak submits rakudobug
<colomon> m​: my %b; %b.classify-list( {.comb}, 20..40 ); say %b.perl
<camelia> rakudo-moar a46b09​: OUTPUT«{"2" => {"0" => [20], "1" =>
[21], "2" => [22], "3" => [23], "4" => [24], "5" => [25], "6" => [26],
"7" => [27], "8" => [28], "9" => [29]}, "3" => {"0" => [30], "1" =>
[31], "2" => [32], "3" => [33], "4" => [34], "5" => [35], "6" => [36],
"7" => [37], "8" …»
<masak> m​: my %b := BagHash.new(); say %b{'foo'}
<camelia> rakudo-moar a46b09​: OUTPUT«0␤»

Notice how postcircumfix​:<{ }> is defined on BagHash, as seen in that
last eval. But something must go wrong inside .classify-list such that
.{} gets called on an Int instead of on the BagHash itself.

From @zoffixznet

Fixed in rakudo/rakudo@8f2279b155
Tests added in Raku/roast@816b913d98

On Thu Aug 27 04​:25​:26 2015, masak wrote​:

<colomon> m​: my %b := BagHash.new(); %b.classify-list( {.comb}, 20..40
); say %b.perl
<camelia> rakudo-moar a46b09​: OUTPUT«postcircumfix​:<{ }> not defined
for type Int [...]
<colomon> masak​: ^^
* masak submits rakudobug
<colomon> m​: my %b; %b.classify-list( {.comb}, 20..40 ); say %b.perl
<camelia> rakudo-moar a46b09​: OUTPUT«{"2" => {"0" => [20], "1" =>
[21], "2" => [22], "3" => [23], "4" => [24], "5" => [25], "6" => [26],
"7" => [27], "8" => [28], "9" => [29]}, "3" => {"0" => [30], "1" =>
[31], "2" => [32], "3" => [33], "4" => [34], "5" => [35], "6" => [36],
"7" => [37], "8" …»
<masak> m​: my %b := BagHash.new(); say %b{'foo'}
<camelia> rakudo-moar a46b09​: OUTPUT«0␤»

Notice how postcircumfix​:<{ }> is defined on BagHash, as seen in that
last eval. But something must go wrong inside .classify-list such that
.{} gets called on an Int instead of on the BagHash itself.

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

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