Formatter inserts unexpected whitespace in if with comments after macro

[homonoidian]

Bug Report

This:

macro x

end

if true    #
  a = "xy" #
end

... formats to this:

macro x
end

if true #
  a = "x   y" #
end

Macro with leading/trailing newlines. Code could be between the macro and ifs, in my case that was several hundred lines:

macro x

end

dofoo(1)
foodo(2)

if true    #
  a = "xy" #
end

... becomes:

macro x
end

dofoo(1)
foodo(2)

if true #
  a = "x   y" #
end

Similarly with multiple ifs:

macro x

end

if n0 #
  a = "xy" #
end

if n01 #
  a = "xy" #
end

if n012 #
  a = "xy" #
end

if n0123 #
  a = "xy" #
end

if n01234 #
  a = "xy" #
end

if n012345 #
  a = "xy" #
end

... formats to:

macro x
end

if n0 #
  a =      "xy" #
end

if n01 #
  a = "    xy" #
end

if n012 #
  a = "x   y" #
end

if n0123 #
  a = "xy  " #
end

if n01234 #
  a = "xy"  #
end

if n012345 #
  a = "xy" #
end

There's also this:

macro x
  
end

if 1 #
  foo #
  xyzzy = "hello world" #
end

... which formats to:

macro x
end

if 1 #
  foo                    #
  xyzz                  y = "hello world" #
end

... and so on.

[kamil-gwozdz]

I wrote a failing spec for it: kamil-gwozdz@bdc5756

I think the problem is that lines and @comment_columns are missmatched here:

crystal/src/compiler/crystal/tools/formatter.cr

Lines 5061 to 5075 in 0cef61e

	max_column = nil
	lines.each_with_index do |line, i|
	comment_column = @comment_columns[i]?
	if comment_column
	if max_column
	lines[i] = align_comment line, i, comment_column, max_column
	else
	max_column = find_max_column(lines, i + 1, comment_column)
	lines[i] = align_comment line, i, comment_column, max_column
	end
	else
	max_column = nil
	end
	end

# lines
["macro x", "end", "", "if true #", "  a = \"xy\" #", "end"] # 6 elements
# @comment_columns
[nil, nil, nil, nil, 8, 11, nil, nil] # 8 elements

I guess it's due to how macros are handled.

[kamil-gwozdz]

It seems like empty lines were removed from lines but they are still referenced in @comment_columns.