The Problem

This code (note the missing comma)

my $x;
{:$x :$x}

produces what I assume is an exception in the compiler:

~/raku $ perl6 test.p6
===SORRY!===
Unknown QAST node type NQPMu

The same thing happens with

• {:x($x) :y($x)}
• {:x<a> :y<b>}
• {:$x :y($x)}

These expressions produce a Hash with two elements:

• {:x($x) :y(1)}
• {:$x :1y}
• `{:

The '$' symbol has a special meaning in the sprintf format string and must be escaped if intended to be used as a literal character. That fact is very briefly described in an offhand manner and, as a result, I, dummy, have twice this year wasted lots of time finding my error. I propose some solutions:

1. better describe it in the docs
2. file an issue with Rakudo to generate a better error m