Blocks defined amid larger expressions will return the entire line

[searls]

Given a line like this:

Then { expect(:foo).to eqish arg_that {|arg| arg.kind_of?(String) } }

Asking the block passed to arg_that its source will return a string of the entire line, not only what was passed to the block.

I imagine this is just a limitation of what #source_location tells you (e.g. no column information). Is there any other way to get at this? Would an AST approach perhaps work?