diff --git a/doc/src/sgml/generate-errcodes-table.pl b/doc/src/sgml/generate-errcodes-table.pl
index 9a1886059b..66a3ee0029 100644
--- a/doc/src/sgml/generate-errcodes-table.pl
+++ b/doc/src/sgml/generate-errcodes-table.pl
@@ -3,8 +3,8 @@
 # Generate the errcodes-table.sgml file from errcodes.txt
 # Copyright (c) 2000-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 print
   "<!-- autogenerated from src/backend/utils/errcodes.txt, do not edit -->\n";
diff --git a/src/backend/parser/check_keywords.pl b/src/backend/parser/check_keywords.pl
index 3862db0727..e6c6c98fb5 100644
--- a/src/backend/parser/check_keywords.pl
+++ b/src/backend/parser/check_keywords.pl
@@ -6,8 +6,8 @@
 # src/backend/parser/check_keywords.pl
 # Copyright (c) 2009-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 my $gram_filename   = $ARGV[0];
 my $kwlist_filename = $ARGV[1];
diff --git a/src/backend/storage/lmgr/generate-lwlocknames.pl b/src/backend/storage/lmgr/generate-lwlocknames.pl
index ca54acdfb0..39cb97f5c3 100644
--- a/src/backend/storage/lmgr/generate-lwlocknames.pl
+++ b/src/backend/storage/lmgr/generate-lwlocknames.pl
@@ -3,8 +3,8 @@
 # Generate lwlocknames.h and lwlocknames.c from lwlocknames.txt
 # Copyright (c) 2000-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 my $lastlockidx = -1;
 my $continue    = "\n";
diff --git a/src/backend/utils/generate-errcodes.pl b/src/backend/utils/generate-errcodes.pl
index 868a163578..1a071fbb1f 100644
--- a/src/backend/utils/generate-errcodes.pl
+++ b/src/backend/utils/generate-errcodes.pl
@@ -3,8 +3,8 @@
 # Generate the errcodes.h header from errcodes.txt
 # Copyright (c) 2000-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 print
   "/* autogenerated from src/backend/utils/errcodes.txt, do not edit */\n";
diff --git a/src/pl/plpgsql/src/generate-plerrcodes.pl b/src/pl/plpgsql/src/generate-plerrcodes.pl
index f74dd0ef03..32d251c8c2 100644
--- a/src/pl/plpgsql/src/generate-plerrcodes.pl
+++ b/src/pl/plpgsql/src/generate-plerrcodes.pl
@@ -3,8 +3,8 @@
 # Generate the plerrcodes.h header from errcodes.txt
 # Copyright (c) 2000-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 print
   "/* autogenerated from src/backend/utils/errcodes.txt, do not edit */\n";
diff --git a/src/pl/plpython/generate-spiexceptions.pl b/src/pl/plpython/generate-spiexceptions.pl
index d7afb8516d..fba603e9ec 100644
--- a/src/pl/plpython/generate-spiexceptions.pl
+++ b/src/pl/plpython/generate-spiexceptions.pl
@@ -3,8 +3,8 @@
 # Generate the spiexceptions.h header from errcodes.txt
 # Copyright (c) 2000-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 print
   "/* autogenerated from src/backend/utils/errcodes.txt, do not edit */\n";
diff --git a/src/pl/tcl/generate-pltclerrcodes.pl b/src/pl/tcl/generate-pltclerrcodes.pl
index 59ea2baab7..43417a4bb4 100644
--- a/src/pl/tcl/generate-pltclerrcodes.pl
+++ b/src/pl/tcl/generate-pltclerrcodes.pl
@@ -3,8 +3,8 @@
 # Generate the pltclerrcodes.h header from errcodes.txt
 # Copyright (c) 2000-2020, PostgreSQL Global Development Group
 
-use warnings;
 use strict;
+use warnings;
 
 print
   "/* autogenerated from src/backend/utils/errcodes.txt, do not edit */\n";