old_contents: # Copyright 2015 The Rust Project Developers. See the COPYRIGHT
  # file at the top-level directory of this distribution and at
  # http://rust-lang.org/COPYRIGHT.
  #
  # Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
  # http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
  # <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
  # option. This file may not be copied, modified, or distributed
  # except according to those terms.
  
  # Digs error codes out of files named 'diagnostics.rs' across
  # the tree, and ensures thare are no duplicates.
  
  import sys, os, re
  
  src_dir = sys.argv[1]
  errcode_map = {}
  error_re = re.compile("(E\d\d\d\d)")
  
  for (dirpath, dirnames, filenames) in os.walk(src_dir):
      if "src/test" in dirpath or "src/llvm" in dirpath:
          # Short circuit for fast
          continue
  
      for filename in filenames:
          if filename != "diagnostics.rs":
              continue
  
          path = os.path.join(dirpath, filename)
  
          with open(path, 'r') as f:
              for line_num, line in enumerate(f, start=1):
                  match = error_re.search(line)
                  if match:
                      errcode = match.group(1)
                      new_record = [(errcode, path, line_num, line)]
                      existing = errcode_map.get(errcode)
                      if existing is not None:
                          # This is a dupe
                          errcode_map[errcode] = existing + new_record
                      else:
                          errcode_map[errcode] = new_record
  
  errors = False
  all_errors = []
  
  for errcode, entries in errcode_map.items():
      all_errors.append(entries[0][0])
      if len(entries) > 1:
          print("error: duplicate error code " + errcode)
          for entry in entries:
              print("{1}: {2}\n{3}".format(*entry))
          errors = True
  
  print("{0} error codes".format(len(errcode_map)))
  print("highest error code: " + max(all_errors))
  
  if errors:
      sys.exit(1)
  
new_contents: # Copyright 2015 The Rust Project Developers. See the COPYRIGHT
  # file at the top-level directory of this distribution and at
  # http://rust-lang.org/COPYRIGHT.
  #
  # Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
  # http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
  # <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
  # option. This file may not be copied, modified, or distributed
  # except according to those terms.
  
  # Digs error codes out of files named 'diagnostics.rs' across
  # the tree, and ensures thare are no duplicates.
  
  import sys
  import os
  import re
  
  src_dir = sys.argv[1]
  errcode_map = {}
  error_re = re.compile("(E\d\d\d\d)")
  
  for (dirpath, dirnames, filenames) in os.walk(src_dir):
      if "src/test" in dirpath or "src/llvm" in dirpath:
          # Short circuit for fast
          continue
  
      for filename in filenames:
          if filename != "diagnostics.rs":
              continue
  
          path = os.path.join(dirpath, filename)
  
          with open(path, 'r') as f:
              for line_num, line in enumerate(f, start=1):
                  match = error_re.search(line)
                  if match:
                      errcode = match.group(1)
                      new_record = [(errcode, path, line_num, line)]
                      existing = errcode_map.get(errcode)
                      if existing is not None:
                          # This is a dupe
                          errcode_map[errcode] = existing + new_record
                      else:
                          errcode_map[errcode] = new_record
  
  errors = False
  all_errors = []
  
  for errcode, entries in errcode_map.items():
      all_errors.append(entries[0][0])
      if len(entries) > 1:
          print("error: duplicate error code " + errcode)
          for entry in entries:
              print("{1}: {2}\n{3}".format(*entry))
          errors = True
  
  print("{0} error codes".format(len(errcode_map)))
  print("highest error code: " + max(all_errors))
  
  if errors:
      sys.exit(1)
  
subject: Fix PEP8 for errorck