Common things that are known to have problems or not work in Rakudo as of 2009-01-02.
Where appropriate, provide a reference to the corresponding RT ticket. Note that we aren't trying to make a list of all known bugs -- that's what RT is for. This should just be for the common issues that people will want to be aware of or work around when playing with Rakudo.
arrays in list declarations -- e.g., my ($b, @a) = ...
arrays and hashes as parameters in methods/subs
reading array/hash elements causes them to autovivify (RT #61882)
incorrect parsing of blocks followed by 'if', 'unless', 'while', 'until', 'given', etc. (RT #57876)