When editing this code in emacs in cperl-mode

use Carp;





sub tst1 {
   carp "bla";
}

sub tst2 {
   tst1()
}

tst2();
[download]

and running M-x mode-compile

I'm getting this output in the compilation window

-*- mode: compilation; default-directory: "~/" -*-
Compilation started at Thu Aug 11 01:37:03


C:/Perl_64/bin\perl.exe -w d:/Users/LanX/AppData/Roaming/tst_carp.pl 
bla at d:/Users/LanX/AppData/Roaming/tst_carp.pl line 8.
	main::tst1() called at d:/Users/LanX/AppData/Roaming/tst_carp.pl line 12
	main::tst2() called at d:/Users/LanX/AppData/Roaming/tst_carp.pl line 15


Compilation finished at Thu Aug 11 01:37:03

Please note that in the last two lines the last digit of the line number (marked blue) is missing.

This means, when I try navigating to the error-line (like clicking) I'll always land in the line 1 instead of 12 or 15.

I nailed down the problem to this part of mode-compile.el and added a regex to match line numbers followed by newlines

(defvar perl-compilation-error-regexp-alist
  ;; Contributed by Martin Jost
  '(
    ;; PERL 4
    ("in file \\([^ ]+\\) at line \\([0-9]+\\).*" 1 2)
    ;; PERL 5   Blubber at FILE line XY, <XY> line ab.
    ("at \\([^ ]+\\) line \\([0-9]+\\)," 1 2)
    ;; PERL 5   Blubber at FILE line XY.
    ("at \\([^ ]+\\) line \\([0-9]+\\)." 1 2)
    ;; PERL 5   Blubber at FILE line XY
    ("at \\([^ ]+\\) line \\([0-9]+\\)\n" 1 2) ; <--- added by LanX
    )
  ;; This look like a paranoiac regexp: could anybody find a better on
+e? (which WORK).
  ;;'(("^[^\n]* \\(file\\|at\\) \\([^ \t\n]+\\) [^\n]*line \\([0-9]+\\
+)[\\.,]" 2 3))
  "Alist that specifies how to match errors in perl output.
[download]

The snippet about a "paranoic regexp" was taken from an old version of cperl-mode.el which now DOES match the newline

from cperl-mode.el 6.2

;; NB as it stands the code in cperl-mode assumes this only has one
;; element. If XEmacs 19 support were dropped, this could all be simpl
+ified.
(defvar cperl-compilation-error-regexp-alist
  ;; This look like a paranoiac regexp: could anybody find a better on
+e? (which WORKS).
  '(("^[^\n]* \\(file\\|at\\) \\([^ \t\n]+\\) [^\n]*line \\([0-9]+\\)[
+\\., \n]"
     2 3))
  "Alist that specifies how to match errors in perl output.")
[download]

please note now its cperl-compilation-error-regexp-alist not perl-compilation-error-regexp-alist

Now my questions:

• Can you reproduce the problem?
• Why is mode-compile using the hard coded perl-compilation-error-regexp-alist instead of the correct one for cperl-mode?
• Where and how can I provide a patch for this issue - mode-compile seems to be unmaintained

Any ideas?

update

• mode-compile-version is "2.28"
• cperl-version is "6.2"
• emacs-version is "24.3.1"