Bad string error occurs when calling `crystal-beginning-of-block` and` crystal-end-of-block` in a block

[brantou]

def twice
  yield
  yield
end

twice do
  puts "hello!"
end

Bad string error occurs when calling crystal-beginning-of-block and crystal-end-of-block in a block(twice).

Crystal 0.24.1 (2017-12-22)
LLVM: 4.0.0
Default target: x86_64-unknown-linux-gnu