Disallow leading spaces in error regexp in interactive mode

haskell-interactive-mode.el

@@ -448,7 +448,7 @@ SESSION, otherwise operate on the current buffer.
                                 (not visibility)))))))
 
 (defconst haskell-interactive-mode-error-regexp
-  "^\\([A-Z]?:?[^\r\n:]+\\):\\([0-9()-:]+\\):?")
+  "^\\(\\(?:[A-Z]:\\)?[^ \r\n:][^\r\n:]*\\):\\([0-9()-:]+\\):?")
 
 (defun haskell-interactive-at-compile-message ()
   "Am I on a compile message?"

tests/interactive-haskell-mode-tests.el

@@ -0,0 +1,51 @@
+;;; interactive-haskell-mode-tests.el --- Tests for Haskell Interactive Mode
+
+;; Copyright © 2016 Athur Fayzrakhmanov. All rights reserved.
+
+;; This file is part of haskell-mode package.
+;; You can contact the authors using GitHub issue tracker:
+;; https://github.com/haskell/haskell-mode/issues
+
+;; This file is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; This file is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to
+;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
+
+;;; Commentary:
+
+;; This package provides regression tests for the package
+;; haskell-interactive-mode.
+
+;;; Code:
+
+
+(require 'ert)
+(require 'haskell-interactive-mode)
+
+(defun should-match (str)
+  (should (eq 0 (string-match-p haskell-interactive-mode-error-regexp str))))
+
+(ert-deftest haskell-interactive-error-regexp-test ()
+  "Tests the regexp `haskell-interactive-mode-error-regexp'"
+  (should (eq 0 (string-match-p haskell-interactive-mode-error-regexp
+                                "/home/user/Test.hs:24:30:")))
+  (should (eq 0 (string-match-p haskell-interactive-mode-error-regexp
+                                "Test.hs:5:18:")))
+  (should (eq 0 (string-match-p haskell-interactive-mode-error-regexp
+                                "Test.hs:7:6: Not in scope: type constructor or class ‘Ty’")))
+  (should (eq 0 (string-match-p haskell-interactive-mode-error-regexp
+                                "Test.hs:9:5: Not in scope: ‘c’")))
+  (should (eq nil (string-match-p haskell-interactive-mode-error-regexp
+                                  ;; leading space
+                                  " Test.hs:8:9:")))
+  )