"error: too deeply nested expressions" for large Perl input file

[Gavin Smith]

In gettext 0.22, there is an error running xgettext with a large input
file:

$ /usr/local/bin/xgettext    HTML.pm     
HTML.pm:8052: error: too deeply nested expressions

This makes "make update-po" break in the Texinfo package.

I have tried to reduce the input file to a minimal case by deleting
chunks of the file but beyond a certain point the error disappears.

For example, just removing the three lines

  foreach my $def_command (keys(%def_commands)) {
    $formatted_line_commands{$def_command} = 1 if 
($line_commands{$def_command}); 
  }

from early in the file makes the error go away.

I expect whatever counting of "nested expressions" is being done
isn't counting correctly.

HTML.pm.xz
Description: Binary data