Crystal macro generates incorrect syntax?

actual.txt

There was a problem expanding macro 'sequential'

Code in src/minimal_example.cr:8:1

 8 | sequential do
     ^
Called macro defined in src/minimal_example.cr:1:1

 1 | macro sequential(&block)

Which expanded to:

   1 |   
   2 | 
 > 3 |   sequence << "first", sequence << "second", sequence << "third", puts(sequence)
                            ^
Error: unexpected token: ,

example.cr

macro sequential(&block)
  {% expressions = block.body.is_a?(Expressions) ? block.body.expressions : [block.body] %}

  {{ *expressions.select { |x| (x.class_name == "Call") }.map { |x| x.block.body } }}
end

sequence = [] of String
sequential do
  first { sequence << "first" }
  second { sequence << "second" }
  third { sequence << "third" }
  last { puts sequence }
end

expected.cr

sequence << "first"
sequence << "second"
sequence << "third"
puts sequence

# or even

sequence << "first";sequence << "second";sequence << "third";puts sequence