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APItest:t/utf8_warn_base.pl: Move a variable outside sub()
[perl5.git] / ext / XS-APItest / t / utf8_warn_base.pl
index 619a554..6f7a36d 100644 (file)
@@ -1,10 +1,11 @@
 #!perl -w
 
 # This is a base file to be used by various .t's in its directory
-# It tests various code points that are "problematic", and verifies that the
-# correct warnings/flags etc are generated when using them.  It also takes the
-# UTF-8 for some of them and perturbs it to be malformed in various ways, and
-# tests that this gets appropriately detected.
+# It tests various malformed UTF-8 sequences and some code points that are
+# "problematic", and verifies that the correct warnings/flags etc are
+# generated when using them.  For the code points, it also takes the UTF-8 and
+# perturbs it to be malformed in various ways, and tests that this gets
+# appropriately detected.
 
 use strict;
 use Test::More;
@@ -17,8 +18,6 @@ BEGIN {
 
 $|=1;
 
-no warnings 'deprecated'; # Some of the below are above IV_MAX on 32 bit
-                          # machines, and that is tested elsewhere
 use XS::APItest;
 
 my @warnings_gotten;
@@ -28,16 +27,73 @@ local $SIG{__WARN__} = sub { my @copy = @_;
                              push @warnings_gotten, map { chomp; $_ } @copy;
                            };
 
+my $highest_non_extended_utf8_cp = (isASCII) ? 0x7FFFFFFF : 0x3FFFFFFF;
 my $native_lowest_continuation_chr = I8_to_native(chr $::lowest_continuation);
 
+# C5 is chosen as it is valid for both ASCII and EBCDIC platforms
+my $known_start_byte = I8_to_native("\xC5");
+
 sub requires_extended_utf8($) {
 
     # Returns a boolean as to whether or not the code point parameter fits
     # into 31 bits, subject to the convention that a negative code point
     # stands for one that overflows the word size, so won't fit in 31 bits.
 
-    my $cp = shift;
-    return $cp > 0x7FFFFFFF;
+    return shift > $highest_non_extended_utf8_cp;
+}
+
+sub is_extended_utf8($) {
+
+    # Returns a boolean as to whether or not the input UTF-8 sequence uses
+    # Perl extended UTF-8.
+
+    my $byte = substr(shift, 0, 1);
+    return ord $byte >= 0xFE if isASCII;
+    return $byte == I8_to_native("\xFF");
+}
+
+sub overflow_discern_len($) {
+
+    # Returns how many bytes are needed to tell if a non-overlong UTF-8
+    # sequence is for a code point that won't fit in the platform's word size.
+    # Only the length of the sequence representing a single code point is
+    # needed.
+
+    if (isASCII) {
+        return ($::is64bit) ? 3 : 1;
+
+        # Below is needed for code points above IV_MAX
+        #return ($::is64bit) ? 3 : ((shift == $::max_bytes)
+        #                           ? 1
+        #                           : 2);
+    }
+
+    return ($::is64bit) ? 2 : 8;
+}
+
+sub overlong_discern_len($) {
+
+    # Returns how many bytes are needed to tell if the input UTF-8 sequence
+    # for a code point is overlong
+
+    my $string = shift;
+    my $length = length $string;
+    my $byte = ord native_to_I8(substr($string, 0, 1));
+    if (isASCII) {
+        return ($byte >= 0xFE)
+                ? ((! $::is64bit)
+                    ? 1
+                    : ($byte == 0xFF) ? 7 : 2)
+                : (($length == 2) ? 1 : 2);
+        # Below is needed for code points above IV_MAX
+        #return ($length == $::max_bytes)
+        #          # This is constrained to 1 on 32-bit machines, as it
+        #          # overflows there
+        #        ? (($::is64bit) ? 7 : 1)
+        #        : (($length == 2) ? 1 : 2);
+    }
+
+    return ($length == $::max_bytes) ? 8 : (($length <= 3) ? 1 : 2);
 }
 
 my @tests;
@@ -54,6 +110,27 @@ my @tests;
         #                          like being a surrogate; 0 indicates we need
         #                          the whole string.  Some categories have a
         #                          default that is used if this is omitted.
+        [ "orphan continuation byte malformation",
+            I8_to_native("$::I8c"),
+            0xFFFD,
+            1,
+        ],
+        [ "overlong malformation, lowest 2-byte",
+            (isASCII) ? "\xc0\x80" : I8_to_native("\xc0\xa0"),
+            0,   # NUL
+        ],
+        [ "overlong malformation, highest 2-byte",
+            (isASCII) ? "\xc1\xbf" : I8_to_native("\xc4\xbf"),
+            (isASCII) ? 0x7F : 0xFF,
+        ],
+        [ "overlong malformation, lowest 3-byte",
+            (isASCII) ? "\xe0\x80\x80" : I8_to_native("\xe0\xa0\xa0"),
+            0,   # NUL
+        ],
+        [ "overlong malformation, highest 3-byte",
+            (isASCII) ? "\xe0\x9f\xbf" : I8_to_native("\xe0\xbf\xbf"),
+            (isASCII) ? 0x7FF : 0x3FF,
+        ],
         [ "lowest surrogate",
             (isASCII) ? "\xed\xa0\x80" : I8_to_native("\xf1\xb6\xa0\xa0"),
             0xD800,
@@ -86,6 +163,14 @@ my @tests;
             (isASCII) ? "\xef\xbf\xbf" : I8_to_native("\xf1\xbf\xbf\xbf"),
             0xFFFF,
         ],
+        [ "overlong malformation, lowest 4-byte",
+            (isASCII) ? "\xf0\x80\x80\x80" : I8_to_native("\xf0\xa0\xa0\xa0"),
+            0,   # NUL
+        ],
+        [ "overlong malformation, highest 4-byte",
+            (isASCII) ? "\xf0\x8F\xbf\xbf" : I8_to_native("\xf0\xaf\xbf\xbf"),
+            (isASCII) ? 0xFFFF : 0x3FFF,
+        ],
         [ "non-character code point U+1FFFE",
             (isASCII) ? "\xf0\x9f\xbf\xbe" : I8_to_native("\xf3\xbf\xbf\xbe"),
             0x1FFFE,
@@ -280,72 +365,156 @@ my @tests;
             (isASCII) ? 0x140000 : 0x200000,
             1,
         ],
-        [ "lowest 32 bit code point",
+        [ "overlong malformation, lowest 5-byte",
             (isASCII)
-            ?  "\xfe\x82\x80\x80\x80\x80\x80"
-            : I8_to_native(
-                "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa2\xa0\xa0\xa0\xa0\xa0\xa0"),
-            0x80000000,
-            (isASCII) ? 1 : 8,
+            ?              "\xf8\x80\x80\x80\x80"
+            : I8_to_native("\xf8\xa0\xa0\xa0\xa0"),
+            0,   # NUL
+        ],
+        [ "overlong malformation, highest 5-byte",
+            (isASCII)
+            ?              "\xf8\x87\xbf\xbf\xbf"
+            : I8_to_native("\xf8\xa7\xbf\xbf\xbf"),
+            (isASCII) ? 0x1FFFFF : 0x3FFFF,
+        ],
+        [ "overlong malformation, lowest 6-byte",
+            (isASCII)
+            ?              "\xfc\x80\x80\x80\x80\x80"
+            : I8_to_native("\xfc\xa0\xa0\xa0\xa0\xa0"),
+            0,   # NUL
+        ],
+        [ "overlong malformation, highest 6-byte",
+            (isASCII)
+            ?              "\xfc\x83\xbf\xbf\xbf\xbf"
+            : I8_to_native("\xfc\xa3\xbf\xbf\xbf\xbf"),
+            (isASCII) ? 0x3FFFFFF : 0x3FFFFF,
+        ],
+        [ "overlong malformation, lowest 7-byte",
+            (isASCII)
+            ?              "\xfe\x80\x80\x80\x80\x80\x80"
+            : I8_to_native("\xfe\xa0\xa0\xa0\xa0\xa0\xa0"),
+            0,   # NUL
         ],
-        [ "highest 32 bit code point",
+        [ "overlong malformation, highest 7-byte",
             (isASCII)
-            ?  "\xfe\x83\xbf\xbf\xbf\xbf\xbf"
+            ?              "\xfe\x81\xbf\xbf\xbf\xbf\xbf"
+            : I8_to_native("\xfe\xa1\xbf\xbf\xbf\xbf\xbf"),
+            (isASCII) ? 0x7FFFFFFF : 0x3FFFFFF,
+        ],
+        [ "highest 31 bit code point",
+            (isASCII)
+            ?  "\xfd\xbf\xbf\xbf\xbf\xbf"
             : I8_to_native(
-               "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa3\xbf\xbf\xbf\xbf\xbf\xbf"),
-            0xFFFFFFFF,
-            (isASCII) ? 1 : 8,
+               "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa1\xbf\xbf\xbf\xbf\xbf\xbf"),
+            0x7FFFFFFF,
+            1,
         ],
-        [ "Lowest 33 bit code point",
+        [ "lowest 32 bit code point",
             (isASCII)
-            ?  "\xfe\x84\x80\x80\x80\x80\x80"
+            ?  "\xfe\x82\x80\x80\x80\x80\x80"
             : I8_to_native(
-                "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa4\xa0\xa0\xa0\xa0\xa0\xa0"),
-            ($::is64bit) ? 0x100000000 : -1,   # Overflows on 32-bit systems
-            (isASCII && ! $::is64bit) ? 2 : 1,
+                "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa2\xa0\xa0\xa0\xa0\xa0\xa0"),
+            ($::is64bit) ? 0x80000000 : -1,   # Overflows on 32-bit systems
+            1,
         ],
+        # Used when UV_MAX is allowed as a code point
+        #[ "highest 32 bit code point",
+        #    (isASCII)
+        #    ?  "\xfe\x83\xbf\xbf\xbf\xbf\xbf"
+        #    : I8_to_native(
+        #       "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa3\xbf\xbf\xbf\xbf\xbf\xbf"),
+        #    0xFFFFFFFF,
+        #],
+        #[ "Lowest 33 bit code point",
+        #    (isASCII)
+        #    ?  "\xfe\x84\x80\x80\x80\x80\x80"
+        #    : I8_to_native(
+        #        "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa4\xa0\xa0\xa0\xa0\xa0\xa0"),
+        #    ($::is64bit) ? 0x100000000 : 0x0,   # Overflows on 32-bit systems
+        #],
     );
 
     if (! $::is64bit) {
         if (isASCII) {
             push @tests,
+                [ "overlong malformation, but naively looks like overflow",
+                    "\xff\x80\x80\x80\x80\x80\x80\x81\xbf\xbf\xbf\xbf\xbf",
+                    0x7FFFFFFF,
+                ],
+                # Used when above IV_MAX are allowed.
+                #[ "overlong malformation, but naively looks like overflow",
+                #    "\xff\x80\x80\x80\x80\x80\x80\x83\xbf\xbf\xbf\xbf\xbf",
+                #    0xFFFFFFFF,
+                #],
                 [ "overflow that old algorithm failed to detect",
                     "\xfe\x86\x80\x80\x80\x80\x80",
                     -1,
-                    2,
                 ];
         }
     }
 
+    push @tests,
+        [ "overlong malformation, lowest max-byte",
+            (isASCII)
+             ?      "\xff\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80"
+             : I8_to_native(
+                    "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
+            0,   # NUL
+        ],
+        [ "overlong malformation, highest max-byte",
+            (isASCII)    # 2**36-1 on ASCII; 2**30-1 on EBCDIC
+             ?      "\xff\x80\x80\x80\x80\x80\x80\xbf\xbf\xbf\xbf\xbf\xbf"
+             : I8_to_native(
+                    "\xff\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xbf\xbf\xbf\xbf\xbf\xbf"),
+            (isASCII) ? (($::is64bit) ? 0xFFFFFFFFF : -1) : 0x3FFFFFFF,
+        ];
+
+    if (isASCII) {
+        push @tests,
+            [ "Lowest code point requiring 13 bytes to represent", # 2**36
+                "\xff\x80\x80\x80\x80\x80\x81\x80\x80\x80\x80\x80\x80",
+                ($::is64bit) ? 0x1000000000 : -1,    # overflows on 32bit
+            ],
+    };
+
     if ($::is64bit) {
         push @tests,
-            [ "highest 64 bit code point",
+            [ "highest 63 bit code point",
               (isASCII)
-              ? "\xff\x80\x8f\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf"
+              ? "\xff\x80\x87\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf"
               : I8_to_native(
-                "\xff\xaf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf"),
-              0xFFFFFFFFFFFFFFFF,
+                "\xff\xa7\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf"),
+              0x7FFFFFFFFFFFFFFF,
               (isASCII) ? 1 : 2,
             ],
-            [ "first 65 bit code point",
+            [ "first 64 bit code point",
               (isASCII)
-              ? "\xff\x80\x9f\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80"
+              ? "\xff\x80\x88\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80"
               : I8_to_native(
-                "\xff\xb0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
+                "\xff\xa8\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
               -1,
-              (isASCII) ? 3 : 2,
             ];
+            # Used when UV_MAX is allowed as a code point
+            #[ "highest 64 bit code point",
+            #  (isASCII)
+            #  ? "\xff\x80\x8f\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf"
+            #  : I8_to_native(
+            #    "\xff\xaf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf"),
+            #  0xFFFFFFFFFFFFFFFF,
+            #  (isASCII) ? 1 : 2,
+            #],
+            #[ "first 65 bit code point",
+            #  (isASCII)
+            #  ? "\xff\x80\x9f\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80"
+            #  : I8_to_native(
+            #    "\xff\xb0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
+            #  0,
+            #];
         if (isASCII) {
             push @tests,
-                [ "Lowest code point requiring 13 bytes to represent",
-                    "\xff\x80\x80\x80\x80\x80\x81\x80\x80\x80\x80\x80\x80",
-                    0x1000000000,
-                    1,
-                ],
                 [ "overflow that old algorithm failed to detect",
                     "\xff\x80\x90\x90\x90\xbf\xbf\xbf\xbf\xbf\xbf\xbf\xbf",
                     -1,
-                    3,
                 ];
         }
         else {
@@ -355,37 +524,32 @@ my @tests;
                     I8_to_native(
                     "\xff\xa0\xa0\xa0\xa0\xa0\xa1\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
                     0x800000000,
-                    7,
+                      40000000
                 ],
                 [ "requires at least 32 bits",
                     I8_to_native(
                     "\xff\xa0\xa0\xa0\xa0\xa1\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
                     0x10000000000,
-                    6,
                 ],
                 [ "requires at least 32 bits",
                     I8_to_native(
                     "\xff\xa0\xa0\xa0\xa1\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
                     0x200000000000,
-                    5,
                 ],
                 [ "requires at least 32 bits",
                     I8_to_native(
                     "\xff\xa0\xa0\xa1\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
                     0x4000000000000,
-                    4,
                 ],
                 [ "requires at least 32 bits",
                     I8_to_native(
                     "\xff\xa0\xa1\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
                     0x80000000000000,
-                    3,
                 ],
                 [ "requires at least 32 bits",
                     I8_to_native(
                     "\xff\xa1\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0"),
                     0x1000000000000000,
-                    2,
                 ];
         }
     }
@@ -437,8 +601,8 @@ my @utf8n_flags_to_text =  ( qw(
         W_NONCHAR
         D_SUPER
         W_SUPER
-        D_ABOVE_31_BIT
-        W_ABOVE_31_BIT
+        D_PERL_EXTENDED
+        W_PERL_EXTENDED
         CHECK_ONLY
         NO_CONFIDENCE_IN_CURLEN_
     ) );
@@ -464,6 +628,17 @@ sub utf8n_display_call($)
          . ')';
 }
 
+my @uvchr_flags_to_text =  ( qw(
+        W_SURROGATE
+        W_NONCHAR
+        W_SUPER
+        W_PERL_EXTENDED
+        D_SURROGATE
+        D_NONCHAR
+        D_SUPER
+        D_PERL_EXTENDED
+) );
+
 sub uvchr_display_call($)
 {
     # Converts an eval string that calls test_uvchr_to_utf8 into a more human
@@ -471,23 +646,13 @@ sub uvchr_display_call($)
     #   test_uvchr_to_utf8n_flags($uv, $flags)
     #diag $_[0];
 
-    my @flags_to_text =  ( qw(
-            W_SURROGATE
-            W_NONCHAR
-            W_SUPER
-            W_ABOVE_31_BIT
-            D_SURROGATE
-            D_NONCHAR
-            D_SUPER
-            D_ABOVE_31_BIT
-       ) );
 
     $_[0] =~ / ^ ( [^(]* \( ) ( \d+ ) , \s* ( \d+ ) \) $ /x;
     my $text = $1;
     my $cp = sprintf "%X", $2;
     my $flags = $3;
 
-    return "${text}0x$cp, " . flags_to_text($flags, \@flags_to_text) . ')';
+    return "${text}0x$cp, " . flags_to_text($flags, \@uvchr_flags_to_text) . ')';
 }
 
 sub do_warnings_test(@)
@@ -538,524 +703,690 @@ sub do_warnings_test(@)
 my $num_test_files = $ENV{TEST_JOBS} || 1;
 $num_test_files = 10 if $num_test_files > 10;
 
+# We only really need to test utf8n_to_uvchr_msgs() once with this flag.
+my $tested_CHECK_ONLY = 0;
+
 my $test_count = -1;
 foreach my $test (@tests) {
-    $test_count++;
-    next if $test_count % $num_test_files != $::TEST_CHUNK;
-
-    my ($testname, $bytes, $allowed_uv, $needed_to_discern_len) = @$test;
-
-    my $length = length $bytes;
-    my $will_overflow = $allowed_uv < 0;
-
-    my $uv_string = sprintf(($allowed_uv < 0x100) ? "%02X" : "%04X", $allowed_uv);
-    my $display_bytes = display_bytes($bytes);
-
-    my $controlling_warning_category;
-    my $utf8n_flag_to_warn;
-    my $utf8n_flag_to_disallow;
-    my $uvchr_flag_to_warn;
-    my $uvchr_flag_to_disallow;
-
-    # We want to test that the independent flags are actually independent.
-    # For example, that a surrogate doesn't trigger a non-character warning,
-    # and conversely, turning off an above-Unicode flag doesn't suppress a
-    # surrogate warning.  Earlier versions of this file used nested loops to
-    # test all possible combinations.  But that creates lots of tests, making
-    # this run too long.  What is now done instead is to use the complement of
-    # the category we are testing to greatly reduce the combinatorial
-    # explosion.  For example, if we have a surrogate and we aren't expecting
-    # a warning about it, we set all the flags for non-surrogates to raise
-    # warnings.  If one shows up, it indicates the flags aren't independent.
-    my $utf8n_flag_to_warn_complement;
-    my $utf8n_flag_to_disallow_complement;
-    my $uvchr_flag_to_warn_complement;
-    my $uvchr_flag_to_disallow_complement;
-
-    # Many of the code points being tested are middling in that if code point
-    # edge cases work, these are very likely to as well.  Because this test
-    # file takes a while to execute, we skip testing the edge effects of code
-    # points deemed middling, while testing their basics and continuing to
-    # fully test the non-middling code points.
-    my $skip_most_tests = 0;
-
-    my $cp_message_qr;      # Pattern that matches the message raised when
-                            # that message contains the problematic code
-                            # point.  The message is the same (currently) both
-                            # when going from/to utf8.
-    my $non_cp_trailing_text;   # The suffix text when the message doesn't
-                                # contain a code point.  (This is a result of
-                                # some sort of malformation that means we
-                                # can't get an exact code poin
-
-    # Is this test malformed from the beginning?  If so, we know to generally
-    # expect that the tests will show it isn't valid.
-    my $initially_malformed = 0;
-
-    if ($will_overflow || $allowed_uv > 0x10FFFF) {
-
-        # Set the SUPER flags; later, we test for ABOVE_31_BIT as well.
-        $utf8n_flag_to_warn     = $::UTF8_WARN_SUPER;
-        $utf8n_flag_to_disallow = $::UTF8_DISALLOW_SUPER;
-        $uvchr_flag_to_warn     = $::UNICODE_WARN_SUPER;
-        $uvchr_flag_to_disallow = $::UNICODE_DISALLOW_SUPER;;
-
-        # Below, we add the flags for non-above-31 bit to the code points that
-        # don't fit that category.  Special tests are done for this category
-        # in the inner loop.
-        $utf8n_flag_to_warn_complement     = $::UTF8_WARN_NONCHAR
-                                            |$::UTF8_WARN_SURROGATE;
-        $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_NONCHAR
-                                            |$::UTF8_DISALLOW_SURROGATE;
-        $uvchr_flag_to_warn_complement     = $::UNICODE_WARN_NONCHAR
-                                            |$::UNICODE_WARN_SURROGATE;
-        $uvchr_flag_to_disallow_complement = $::UNICODE_DISALLOW_NONCHAR
-                                            |$::UNICODE_DISALLOW_SURROGATE;
-        $controlling_warning_category = 'non_unicode';
-
-        if ($will_overflow) {  # This is realy a malformation
-            $non_cp_trailing_text = "if you see this, there is an error";
-            $cp_message_qr = qr/\Q$non_cp_trailing_text\E/;
-            $initially_malformed = 1;
-        }
-        elsif (requires_extended_utf8($allowed_uv)) {
-            $cp_message_qr = qr/\QCode point 0x$uv_string is not Unicode,\E
-                                \Q and not portable\E/x;
-            $non_cp_trailing_text = "is for a non-Unicode code point, and is not portable";
-        }
-        else {
-            $cp_message_qr = qr/\QCode point 0x$uv_string is not Unicode,\E
-                                \Q may not be portable\E/x;
-            $non_cp_trailing_text = "is for a non-Unicode code point, may not"
-                                . " be portable";
-            $utf8n_flag_to_warn_complement     |= $::UTF8_WARN_ABOVE_31_BIT;
-            $utf8n_flag_to_disallow_complement |= $::UTF8_DISALLOW_ABOVE_31_BIT;
-            $uvchr_flag_to_warn_complement     |= $::UNICODE_WARN_ABOVE_31_BIT;
-            $uvchr_flag_to_disallow_complement
-                                            |= $::UNICODE_DISALLOW_ABOVE_31_BIT;
-        }
-    }
-    elsif ($allowed_uv >= 0xD800 && $allowed_uv <= 0xDFFF) {
-        $cp_message_qr = qr/UTF-16 surrogate U\+$uv_string/;
-        $non_cp_trailing_text = "is for a surrogate";
-        $needed_to_discern_len = 2 unless defined $needed_to_discern_len;
-        $skip_most_tests = 1 if $allowed_uv > 0xD800 && $allowed_uv < 0xDFFF;
-
-        $utf8n_flag_to_warn     = $::UTF8_WARN_SURROGATE;
-        $utf8n_flag_to_disallow = $::UTF8_DISALLOW_SURROGATE;
-        $uvchr_flag_to_warn     = $::UNICODE_WARN_SURROGATE;
-        $uvchr_flag_to_disallow = $::UNICODE_DISALLOW_SURROGATE;;
-
-        $utf8n_flag_to_warn_complement     = $::UTF8_WARN_NONCHAR
-                                            |$::UTF8_WARN_SUPER
-                                            |$::UTF8_WARN_ABOVE_31_BIT;
-        $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_NONCHAR
-                                            |$::UTF8_DISALLOW_SUPER
-                                            |$::UTF8_DISALLOW_ABOVE_31_BIT;
-        $uvchr_flag_to_warn_complement     = $::UNICODE_WARN_NONCHAR
-                                            |$::UNICODE_WARN_SUPER
-                                            |$::UNICODE_WARN_ABOVE_31_BIT;
-        $uvchr_flag_to_disallow_complement = $::UNICODE_DISALLOW_NONCHAR
-                                            |$::UNICODE_DISALLOW_SUPER
-                                            |$::UNICODE_DISALLOW_ABOVE_31_BIT;
-        $controlling_warning_category = 'surrogate';
-    }
-    elsif (   ($allowed_uv >= 0xFDD0 && $allowed_uv <= 0xFDEF)
-           || ($allowed_uv & 0xFFFE) == 0xFFFE)
-    {
-        $cp_message_qr = qr/\QUnicode non-character U+$uv_string\E
-                            \Q is not recommended for open interchange\E/x;
-        $non_cp_trailing_text = "if you see this, there is an error";
-        $needed_to_discern_len = $length unless defined $needed_to_discern_len;
-        if (   ($allowed_uv > 0xFDD0 && $allowed_uv < 0xFDEF)
-            || ($allowed_uv > 0xFFFF && $allowed_uv < 0x10FFFE))
-        {
-            $skip_most_tests = 1;
-        }
-
-        $utf8n_flag_to_warn     = $::UTF8_WARN_NONCHAR;
-        $utf8n_flag_to_disallow = $::UTF8_DISALLOW_NONCHAR;
-        $uvchr_flag_to_warn     = $::UNICODE_WARN_NONCHAR;
-        $uvchr_flag_to_disallow = $::UNICODE_DISALLOW_NONCHAR;;
-
-        $utf8n_flag_to_warn_complement     = $::UTF8_WARN_SURROGATE
-                                            |$::UTF8_WARN_SUPER
-                                            |$::UTF8_WARN_ABOVE_31_BIT;
-        $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_SURROGATE
-                                            |$::UTF8_DISALLOW_SUPER
-                                            |$::UTF8_DISALLOW_ABOVE_31_BIT;
-        $uvchr_flag_to_warn_complement     = $::UNICODE_WARN_SURROGATE
-                                            |$::UNICODE_WARN_SUPER
-                                            |$::UNICODE_WARN_ABOVE_31_BIT;
-        $uvchr_flag_to_disallow_complement = $::UNICODE_DISALLOW_SURROGATE
-                                            |$::UNICODE_DISALLOW_SUPER
-                                            |$::UNICODE_DISALLOW_ABOVE_31_BIT;
-
-        $controlling_warning_category = 'nonchar';
-    }
-    else {
-        die "Can't figure out what type of warning to test for $testname"
-    }
-
-    die 'Didn\'t set $needed_to_discern_len for ' . $testname
-                                        unless defined $needed_to_discern_len;
-
-    {   # First test the isFOO calls
-        use warnings; no warnings 'deprecated';   # Make sure these don't raise warnings
-        undef @warnings_gotten;
-
-        my $ret = test_isUTF8_CHAR($bytes, $length);
-        my $ret_flags = test_isUTF8_CHAR_flags($bytes, $length, 0);
-        if ($initially_malformed) {
-            is($ret, 0, "For $testname: isUTF8_CHAR() returns 0");
-            is($ret_flags, 0, "    And isUTF8_CHAR_flags() returns 0");
-        }
-        else {
-            is($ret, $length,
-               "For $testname: isUTF8_CHAR() returns expected length: $length");
-            is($ret_flags, $length, "    And isUTF8_CHAR_flags(...,0)"
-                                  . " returns expected length: $length");
-        }
-        is(scalar @warnings_gotten, 0,
-                "    And neither isUTF8_CHAR() nor isUTF8_CHAR()_flags generated"
-              . " any warnings")
-          or output_warnings(@warnings_gotten);
-
-        undef @warnings_gotten;
-        $ret = test_isSTRICT_UTF8_CHAR($bytes, $length);
-        if ($initially_malformed) {
-            is($ret, 0, "    And isSTRICT_UTF8_CHAR() returns 0");
-        }
-        else {
-            my $expected_ret = (   $testname =~ /surrogate|non-character/
-                                || $allowed_uv > 0x10FFFF)
-                               ? 0
-                               : $length;
-            is($ret, $expected_ret, "    And isSTRICT_UTF8_CHAR() returns"
-                                  . " expected length: $expected_ret");
-            $ret = test_isUTF8_CHAR_flags($bytes, $length,
-                                          $::UTF8_DISALLOW_ILLEGAL_INTERCHANGE);
-            is($ret, $expected_ret,
-                    "    And isUTF8_CHAR_flags('DISALLOW_ILLEGAL_INTERCHANGE')"
-                    . " acts like isSTRICT_UTF8_CHAR");
-        }
-        is(scalar @warnings_gotten, 0,
-                "    And neither isSTRICT_UTF8_CHAR() nor isUTF8_CHAR_flags"
-              . " generated any warnings")
-          or output_warnings(@warnings_gotten);
-
-        undef @warnings_gotten;
-        $ret = test_isC9_STRICT_UTF8_CHAR($bytes, $length);
-        if ($initially_malformed) {
-            is($ret, 0, "    And isC9_STRICT_UTF8_CHAR() returns 0");
-        }
-        else {
-            my $expected_ret = (   $testname =~ /surrogate/
-                                || $allowed_uv > 0x10FFFF)
-                               ? 0
-                               : $length;
-            is($ret, $expected_ret, "    And isC9_STRICT_UTF8_CHAR()"
-                                   ." returns expected length: $expected_ret");
-            $ret = test_isUTF8_CHAR_flags($bytes, $length,
-                                        $::UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE);
-            is($ret, $expected_ret,
-                  "    And isUTF8_CHAR_flags('DISALLOW_ILLEGAL_C9_INTERCHANGE')"
-                . " acts like isC9_STRICT_UTF8_CHAR");
-        }
-        is(scalar @warnings_gotten, 0,
-                "    And neither isC9_STRICT_UTF8_CHAR() nor isUTF8_CHAR_flags"
-              . " generated any warnings")
-          or output_warnings(@warnings_gotten);
+  $test_count++;
+  next if $test_count % $num_test_files != $::TEST_CHUNK;
+
+  my ($testname, $bytes, $allowed_uv, $needed_to_discern_len) = @$test;
+
+  my $length = length $bytes;
+  my $initially_overlong = $testname =~ /overlong/;
+  my $initially_orphan   = $testname =~ /orphan/;
+  my $will_overflow = $allowed_uv < 0;
+
+  my $uv_string = sprintf(($allowed_uv < 0x100) ? "%02X" : "%04X", $allowed_uv);
+  my $display_bytes = display_bytes($bytes);
+
+  my $controlling_warning_category;
+  my $utf8n_flag_to_warn;
+  my $utf8n_flag_to_disallow;
+  my $uvchr_flag_to_warn;
+  my $uvchr_flag_to_disallow;
+
+  # We want to test that the independent flags are actually independent.
+  # For example, that a surrogate doesn't trigger a non-character warning,
+  # and conversely, turning off an above-Unicode flag doesn't suppress a
+  # surrogate warning.  Earlier versions of this file used nested loops to
+  # test all possible combinations.  But that creates lots of tests, making
+  # this run too long.  What is now done instead is to use the complement of
+  # the category we are testing to greatly reduce the combinatorial
+  # explosion.  For example, if we have a surrogate and we aren't expecting
+  # a warning about it, we set all the flags for non-surrogates to raise
+  # warnings.  If one shows up, it indicates the flags aren't independent.
+  my $utf8n_flag_to_warn_complement;
+  my $utf8n_flag_to_disallow_complement;
+  my $uvchr_flag_to_warn_complement;
+  my $uvchr_flag_to_disallow_complement;
+
+  # Many of the code points being tested are middling in that if code point
+  # edge cases work, these are very likely to as well.  Because this test
+  # file takes a while to execute, we skip testing the edge effects of code
+  # points deemed middling, while testing their basics and continuing to
+  # fully test the non-middling code points.
+  my $skip_most_tests = 0;
+
+  my $cp_message_qr;      # Pattern that matches the message raised when
+                          # that message contains the problematic code
+                          # point.  The message is the same (currently) both
+                          # when going from/to utf8.
+  my $non_cp_trailing_text;   # The suffix text when the message doesn't
+                              # contain a code point.  (This is a result of
+                              # some sort of malformation that means we
+                              # can't get an exact code poin
+  my $extended_cp_message_qr = qr/\QCode point 0x$uv_string is not Unicode,\E
+                      \Q requires a Perl extension, and so is not\E
+                      \Q portable\E/x;
+  my $extended_non_cp_trailing_text
+                      = "is a Perl extension, and so is not portable";
+
+  # What bytes should have been used to specify a code point that has been
+  # specified as an overlong.
+  my $correct_bytes_for_overlong;
+
+  # Is this test malformed from the beginning?  If so, we know to generally
+  # expect that the tests will show it isn't valid.
+  my $initially_malformed = 0;
+
+  if ($initially_overlong || $initially_orphan) {
+      $non_cp_trailing_text = "if you see this, there is an error";
+      $cp_message_qr = qr/\Q$non_cp_trailing_text\E/;
+      $initially_malformed = 1;
+      $utf8n_flag_to_warn     = 0;
+      $utf8n_flag_to_disallow = 0;
+
+      $utf8n_flag_to_warn_complement =     $::UTF8_WARN_SURROGATE;
+      $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_SURROGATE;
+      if (! $will_overflow && $allowed_uv <= 0x10FFFF) {
+          $utf8n_flag_to_warn_complement     |= $::UTF8_WARN_SUPER;
+          $utf8n_flag_to_disallow_complement |= $::UTF8_DISALLOW_SUPER;
+          if (($allowed_uv & 0xFFFF) != 0xFFFF) {
+              $utf8n_flag_to_warn_complement      |= $::UTF8_WARN_NONCHAR;
+              $utf8n_flag_to_disallow_complement  |= $::UTF8_DISALLOW_NONCHAR;
+          }
+      }
+      if (! is_extended_utf8($bytes)) {
+          $utf8n_flag_to_warn_complement |= $::UTF8_WARN_PERL_EXTENDED;
+          $utf8n_flag_to_disallow_complement  |= $::UTF8_DISALLOW_PERL_EXTENDED;
+      }
 
-        foreach my $disallow_type (0..2) {
-            # 0 is don't disallow this type of code point
-            # 1 is do disallow
-            # 2 is do disallow, but only for above 31 bit
+      $controlling_warning_category = 'utf8';
 
-            my $disallow_flags;
-            my $expected_ret;
+      if ($initially_overlong) {
+          if (! defined $needed_to_discern_len) {
+              $needed_to_discern_len = overlong_discern_len($bytes);
+          }
+          $correct_bytes_for_overlong = display_bytes_no_quotes(chr $allowed_uv);
+      }
+  }
+  elsif($will_overflow || $allowed_uv > 0x10FFFF) {
+
+      # Set the SUPER flags; later, we test for PERL_EXTENDED as well.
+      $utf8n_flag_to_warn     = $::UTF8_WARN_SUPER;
+      $utf8n_flag_to_disallow = $::UTF8_DISALLOW_SUPER;
+      $uvchr_flag_to_warn     = $::UNICODE_WARN_SUPER;
+      $uvchr_flag_to_disallow = $::UNICODE_DISALLOW_SUPER;;
+
+      # Below, we add the flags for non-perl_extended to the code points
+      # that don't fit that category.  Special tests are done for this
+      # category in the inner loop.
+      $utf8n_flag_to_warn_complement     = $::UTF8_WARN_NONCHAR
+                                          |$::UTF8_WARN_SURROGATE;
+      $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_NONCHAR
+                                          |$::UTF8_DISALLOW_SURROGATE;
+      $uvchr_flag_to_warn_complement     = $::UNICODE_WARN_NONCHAR
+                                          |$::UNICODE_WARN_SURROGATE;
+      $uvchr_flag_to_disallow_complement = $::UNICODE_DISALLOW_NONCHAR
+                                          |$::UNICODE_DISALLOW_SURROGATE;
+      $controlling_warning_category = 'non_unicode';
+
+      if ($will_overflow) {  # This is realy a malformation
+          $non_cp_trailing_text = "if you see this, there is an error";
+          $cp_message_qr = qr/\Q$non_cp_trailing_text\E/;
+          $initially_malformed = 1;
+          if (! defined $needed_to_discern_len) {
+              $needed_to_discern_len = overflow_discern_len($length);
+          }
+      }
+      elsif (requires_extended_utf8($allowed_uv)) {
+          $cp_message_qr = $extended_cp_message_qr;
+          $non_cp_trailing_text = $extended_non_cp_trailing_text;
+          $needed_to_discern_len = 1 unless defined $needed_to_discern_len;
+      }
+      else {
+          $cp_message_qr = qr/\QCode point 0x$uv_string is not Unicode,\E
+                              \Q may not be portable\E/x;
+          $non_cp_trailing_text = "is for a non-Unicode code point, may not"
+                              . " be portable";
+          $utf8n_flag_to_warn_complement     |= $::UTF8_WARN_PERL_EXTENDED;
+          $utf8n_flag_to_disallow_complement
+                                          |= $::UTF8_DISALLOW_PERL_EXTENDED;
+          $uvchr_flag_to_warn_complement |= $::UNICODE_WARN_PERL_EXTENDED;
+          $uvchr_flag_to_disallow_complement
+                                      |= $::UNICODE_DISALLOW_PERL_EXTENDED;
+      }
+  }
+  elsif ($allowed_uv >= 0xD800 && $allowed_uv <= 0xDFFF) {
+      $cp_message_qr = qr/UTF-16 surrogate U\+$uv_string/;
+      $non_cp_trailing_text = "is for a surrogate";
+      $needed_to_discern_len = 2 unless defined $needed_to_discern_len;
+      $skip_most_tests = 1 if $allowed_uv > 0xD800 && $allowed_uv < 0xDFFF;
+
+      $utf8n_flag_to_warn     = $::UTF8_WARN_SURROGATE;
+      $utf8n_flag_to_disallow = $::UTF8_DISALLOW_SURROGATE;
+      $uvchr_flag_to_warn     = $::UNICODE_WARN_SURROGATE;
+      $uvchr_flag_to_disallow = $::UNICODE_DISALLOW_SURROGATE;;
+
+      $utf8n_flag_to_warn_complement     = $::UTF8_WARN_NONCHAR
+                                          |$::UTF8_WARN_SUPER
+                                          |$::UTF8_WARN_PERL_EXTENDED;
+      $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_NONCHAR
+                                          |$::UTF8_DISALLOW_SUPER
+                                          |$::UTF8_DISALLOW_PERL_EXTENDED;
+      $uvchr_flag_to_warn_complement     = $::UNICODE_WARN_NONCHAR
+                                          |$::UNICODE_WARN_SUPER
+                                          |$::UNICODE_WARN_PERL_EXTENDED;
+      $uvchr_flag_to_disallow_complement = $::UNICODE_DISALLOW_NONCHAR
+                                          |$::UNICODE_DISALLOW_SUPER
+                                          |$::UNICODE_DISALLOW_PERL_EXTENDED;
+      $controlling_warning_category = 'surrogate';
+  }
+  elsif (   ($allowed_uv >= 0xFDD0 && $allowed_uv <= 0xFDEF)
+          || ($allowed_uv & 0xFFFE) == 0xFFFE)
+  {
+      $cp_message_qr = qr/\QUnicode non-character U+$uv_string\E
+                          \Q is not recommended for open interchange\E/x;
+      $non_cp_trailing_text = "if you see this, there is an error";
+      $needed_to_discern_len = $length unless defined $needed_to_discern_len;
+      if (   ($allowed_uv > 0xFDD0 && $allowed_uv < 0xFDEF)
+          || ($allowed_uv > 0xFFFF && $allowed_uv < 0x10FFFE))
+      {
+          $skip_most_tests = 1;
+      }
 
-            if ($initially_malformed) {
+      $utf8n_flag_to_warn     = $::UTF8_WARN_NONCHAR;
+      $utf8n_flag_to_disallow = $::UTF8_DISALLOW_NONCHAR;
+      $uvchr_flag_to_warn     = $::UNICODE_WARN_NONCHAR;
+      $uvchr_flag_to_disallow = $::UNICODE_DISALLOW_NONCHAR;;
+
+      $utf8n_flag_to_warn_complement     = $::UTF8_WARN_SURROGATE
+                                          |$::UTF8_WARN_SUPER
+                                          |$::UTF8_WARN_PERL_EXTENDED;
+      $utf8n_flag_to_disallow_complement = $::UTF8_DISALLOW_SURROGATE
+                                          |$::UTF8_DISALLOW_SUPER
+                                          |$::UTF8_DISALLOW_PERL_EXTENDED;
+      $uvchr_flag_to_warn_complement     = $::UNICODE_WARN_SURROGATE
+                                          |$::UNICODE_WARN_SUPER
+                                          |$::UNICODE_WARN_PERL_EXTENDED;
+      $uvchr_flag_to_disallow_complement = $::UNICODE_DISALLOW_SURROGATE
+                                          |$::UNICODE_DISALLOW_SUPER
+                                          |$::UNICODE_DISALLOW_PERL_EXTENDED;
+
+      $controlling_warning_category = 'nonchar';
+  }
+  else {
+      die "Can't figure out what type of warning to test for $testname"
+  }
+
+  die 'Didn\'t set $needed_to_discern_len for ' . $testname
+                                      unless defined $needed_to_discern_len;
+
+  # We try various combinations of malformations that can occur
+  foreach my $short (0, 1) {
+    next if $skip_most_tests && $short;
+    foreach my $unexpected_noncont (0, 1) {
+      next if $skip_most_tests && $unexpected_noncont;
+      foreach my $overlong (0, 1) {
+        next if $overlong && $skip_most_tests;
+        next if $initially_overlong && ! $overlong;
+
+        # If we're creating an overlong, it can't be longer than the
+        # maximum length, so skip if we're already at that length.
+        next if   (! $initially_overlong && $overlong)
+                  &&  $length >= $::max_bytes;
+
+        my $this_cp_message_qr = $cp_message_qr;
+        my $this_non_cp_trailing_text = $non_cp_trailing_text;
+
+        foreach my $malformed_allow_type (0..2) {
+          # 0 don't allow this malformation; ignored if no malformation
+          # 1 allow, with REPLACEMENT CHARACTER returned
+          # 2 allow, with intended code point returned.  All malformations
+          #   other than overlong can't determine the intended code point,
+          #   so this isn't valid for them.
+          next if     $malformed_allow_type == 2
+                  && ($will_overflow || $short || $unexpected_noncont);
+          next if $skip_most_tests && $malformed_allow_type;
+
+          # Here we are in the innermost loop for malformations.  So we
+          # know which ones are in effect.  Can now change the input to be
+          # appropriately malformed.  We also can set up certain other
+          # things now, like whether we expect a return flag from this
+          # malformation, and which flag.
+
+          my $this_bytes = $bytes;
+          my $this_length = $length;
+          my $this_expected_len = $length;
+          my $this_needed_to_discern_len = $needed_to_discern_len;
+
+          my @malformation_names;
+          my @expected_malformation_warnings;
+          my @expected_malformation_return_flags;
+
+          # Contains the flags for any allowed malformations.  Currently no
+          # combinations of on/off are tested for.  It's either all are
+          # allowed, or none are.
+          my $allow_flags = 0;
+          my $overlong_is_in_perl_extended_utf8 = 0;
+          my $dont_use_overlong_cp = 0;
+
+          if ($initially_orphan) {
+              next if $overlong || $short || $unexpected_noncont;
+          }
 
-                # Malformations are by default disallowed, so testing with
-                # $disallow_type equal to 0 is sufficicient.
-                next if $disallow_type;
+          if ($overlong) {
+              if (! $initially_overlong) {
+                  my $new_expected_len;
+
+                  # To force this malformation, we convert the original start
+                  # byte into a continuation byte with the same data bits as
+                  # originally. ...
+                  my $start_byte = substr($this_bytes, 0, 1);
+                  my $converted_to_continuation_byte
+                                          = start_byte_to_cont($start_byte);
+
+                  # ... Then we prepend it with a known overlong sequence.
+                  # This should evaluate to the exact same code point as the
+                  # original.  We try to avoid an overlong using Perl
+                  # extended UTF-8.  The code points are the highest
+                  # representable as overlongs on the respective platform
+                  # without using extended UTF-8.
+                  if (native_to_I8($start_byte) lt "\xFC") {
+                      $start_byte = I8_to_native("\xFC");
+                      $new_expected_len = 6;
+                  }
+                  elsif (! isASCII && native_to_I8($start_byte) lt "\xFE") {
+
+                      # FE is not extended UTF-8 on EBCDIC
+                      $start_byte = I8_to_native("\xFE");
+                      $new_expected_len = 7;
+                  }
+                  else {  # Must use extended UTF-8.  On ASCII platforms, we
+                          # could express some overlongs here starting with
+                          # \xFE, but there's no real reason to do so.
+                      $overlong_is_in_perl_extended_utf8 = 1;
+                      $start_byte = I8_to_native("\xFF");
+                      $new_expected_len = $::max_bytes;
+                      $this_cp_message_qr = $extended_cp_message_qr;
+
+                      # The warning that gets raised doesn't include the
+                      # code point in the message if the code point can be
+                      # expressed without using extended UTF-8, but the
+                      # particular overlong sequence used is in extended
+                      # UTF-8.  To do otherwise would be confusing to the
+                      # user, as it would claim the code point requires
+                      # extended, when it doesn't.
+                      $dont_use_overlong_cp = 1
+                                  unless requires_extended_utf8($allowed_uv);
+                      $this_non_cp_trailing_text
+                                            = $extended_non_cp_trailing_text;
+                  }
+
+                  # Splice in the revise continuation byte, preceded by the
+                  # start byte and the proper number of the lowest
+                  # continuation bytes.
+                  $this_bytes =   $start_byte
+                              . ($native_lowest_continuation_chr
+                                  x (  $new_expected_len
+                                      - 1
+                                      - length($this_bytes)))
+                              .  $converted_to_continuation_byte
+                              .  substr($this_bytes, 1);
+                  $this_length = length($this_bytes);
+                  $this_needed_to_discern_len =    $new_expected_len
+                                              - (  $this_expected_len
+                                              - $this_needed_to_discern_len);
+                  $this_expected_len = $new_expected_len;
+              }
+          }
 
-                $disallow_flags = 0;
-                $expected_ret = 0;
-            }
-            elsif ($disallow_type == 1) {
-                $disallow_flags = $utf8n_flag_to_disallow;
-                $expected_ret = 0;
-            }
-            elsif ($disallow_type == 2) {
-                next if ! requires_extended_utf8($allowed_uv);
-                $disallow_flags = $::UTF8_DISALLOW_ABOVE_31_BIT;
-                $expected_ret = 0;
-            }
-            else {  # type is 0
-                $disallow_flags = $utf8n_flag_to_disallow_complement;
-                $expected_ret = $length;
-            }
+          if ($short) {
 
-            $ret = test_isUTF8_CHAR_flags($bytes, $length, $disallow_flags);
-            is($ret, $expected_ret, "    And isUTF8_CHAR_flags("
-                                  . "$display_bytes, $disallow_flags) returns "
-                                  . $expected_ret)
-             or diag "The flags mean "
-              . flags_to_text($disallow_flags, \@utf8n_flags_to_text);
-
-            is(scalar @warnings_gotten, 0,
-                    "    And isUTF8_CHAR_flags(...) generated no warnings")
-            or output_warnings(@warnings_gotten);
-
-            # Test partial character handling, for each byte not a full character
-            my $did_test_partial = 0;
-            for (my $j = 1; $j < $length - 1; $j++) {
-                $did_test_partial = 1;
-                my $partial = substr($bytes, 0, $j);
-                my $ret_should_be;
-                my $comment;
-                if ($disallow_type || $initially_malformed) {
-                    $ret_should_be = 0;
-                    $comment = "disallowed";
-                    if ($j < $needed_to_discern_len) {
-                        $ret_should_be = 1;
-                        $comment .= ", but need $needed_to_discern_len"
-                                 . " bytes to discern:";
-                    }
-                }
-                else {
-                    $ret_should_be = 1;
-                    $comment = "allowed";
-                }
+              # To force this malformation, just tell the test to not look
+              # as far as it should into the input.
+              $this_length--;
+              $this_expected_len--;
 
-                undef @warnings_gotten;
+              $allow_flags |= $::UTF8_ALLOW_SHORT if $malformed_allow_type;
+          }
 
-                $ret = test_is_utf8_valid_partial_char_flags($partial, $j,
-                                                             $disallow_flags);
-                is($ret, $ret_should_be,
-                    "    And is_utf8_valid_partial_char_flags("
-                    . display_bytes($partial)
-                    . ", $disallow_flags), $comment: returns $ret_should_be")
-                 or diag "The flags mean "
-                  . flags_to_text($disallow_flags, \@utf8n_flags_to_text);
-            }
+          if ($unexpected_noncont) {
 
-            if ($did_test_partial) {
-                is(scalar @warnings_gotten, 0,
-                        "    And is_utf8_valid_partial_char_flags()"
-                        . " generated no warnings for any of the lengths")
-                    or output_warnings(@warnings_gotten);
-            }
-        }
-    }
+              # To force this malformation, change the final continuation
+              # byte into a start byte.
+              my $pos = ($short) ? -2 : -1;
+              substr($this_bytes, $pos, 1) = $known_start_byte;
+              $this_expected_len--;
+          }
 
-    # Now test the to/from UTF-8 calls
-    # This is more complicated than the malformations tested in other files in
-    # this directory, as there are several orthogonal variables involved.  We
-    # test most possible combinations
-
-    # We try various combinations of malformations that can occur
-    foreach my $short (0, 1) {
-      next if $skip_most_tests && $short;
-      foreach my $unexpected_noncont (0, 1) {
-        next if $skip_most_tests && $unexpected_noncont;
-        foreach my $overlong (0, 1) {
-          next if $overlong && $skip_most_tests;
-
-          # If we're creating an overlong, it can't be longer than the
-          # maximum length, so skip if we're already at that length.
-          next if $overlong && $length >= $::max_bytes;
-
-          foreach my $malformed_allow_type (0..2) {
-            # 0 don't allow this malformation; ignored if no malformation
-            # 1 allow, with REPLACEMENT CHARACTER returned
-            # 2 allow, with intended code point returned.  All malformations
-            #   other than overlong can't determine the intended code point,
-            #   so this isn't valid for them.
-            next if     $malformed_allow_type == 2
-                    && ($will_overflow || $short || $unexpected_noncont);
-            next if $skip_most_tests && $malformed_allow_type;
-
-            # Here we are in the innermost loop for malformations.  So we
-            # know which ones are in effect.  Can now change the input to be
-            # appropriately malformed.  We also can set up certain other
-            # things now, like whether we expect a return flag from this
-            # malformation, and which flag.
-
-            my $this_bytes = $bytes;
-            my $this_length = $length;
-            my $this_expected_len = $length;
-            my $this_needed_to_discern_len = $needed_to_discern_len;
-
-            my @malformation_names;
-            my @expected_malformation_warnings;
-            my @expected_malformation_return_flags;
-
-            # Contains the flags for any allowed malformations.  Currently no
-            # combinations of on/off are tested for.  It's either all are
-            # allowed, or none are.
-            my $allow_flags = 0;
-
-            if ($overlong) {
-                my $new_expected_len;
-
-                # To force this malformation, we convert the original start
-                # byte into a continuation byte with the same data bits as
-                # originally. ...
-                my $start_byte = substr($this_bytes, 0, 1);
-                my $converted_to_continuation_byte
-                                            = start_byte_to_cont($start_byte);
-
-                # ... Then we prepend it with a known overlong sequence.  This
-                # should evaluate to the exact same code point as the
-                # original.  We try to avoid an overlong using Perl extended
-                # UTF-8.  The code points are the highest representable as
-                # overlongs on the respective platform without using extended
-                # UTF-8.
-                if (native_to_I8($start_byte) lt "\xFC") {
-                    $start_byte = I8_to_native("\xFC");
-                    $new_expected_len = 6;
-                }
-                elsif (! isASCII && native_to_I8($start_byte) lt "\xFE") {
+          # The whole point of a test that is malformed from the beginning
+          # is to test for that malformation.  If we've modified things so
+          # much that we don't have enough information to detect that
+          # malformation, there's no point in testing.
+          next if    $initially_malformed
+                  && $this_expected_len < $this_needed_to_discern_len;
+
+          # Here, we've transformed the input with all of the desired
+          # non-overflow malformations.  We are now in a position to
+          # construct any potential warnings for those malformations.  But
+          # it's a pain to get the detailed messages exactly right, so for
+          # now XXX, only do so for those that return an explicit code
+          # point.
+
+          if ($initially_orphan) {
+              push @malformation_names, "orphan continuation";
+              push @expected_malformation_return_flags,
+                                                  $::UTF8_GOT_CONTINUATION;
+              $allow_flags |= $::UTF8_ALLOW_CONTINUATION
+                                                  if $malformed_allow_type;
+              push @expected_malformation_warnings, qr/unexpected continuation/;
+          }
 
-                    # FE is not extended UTF-8 on EBCDIC
-                    $start_byte = I8_to_native("\xFE");
-                    $new_expected_len = 7;
-                }
-                else {  # Must use extended UTF-8.  On ASCII platforms, we
-                        # could express some overlongs here starting with
-                        # \xFE, but there's no real reason to do so.
-                    $start_byte = I8_to_native("\xFF");
-                    $new_expected_len = $::max_bytes;
-                }
+          if ($overlong) {
+              push @malformation_names, 'overlong';
+              push @expected_malformation_return_flags, $::UTF8_GOT_LONG;
 
-                # Splice in the revise continuation byte, preceded by the
-                # start byte and the proper number of the lowest continuation
-                # bytes.
-                $this_bytes =   $start_byte
-                             . ($native_lowest_continuation_chr
-                                x ( $new_expected_len - 1 - length($this_bytes)))
-                             .  $converted_to_continuation_byte
-                             .  substr($this_bytes, 1);
-                $this_length = length($this_bytes);
-                $this_needed_to_discern_len =    $new_expected_len
-                                            - (  $this_expected_len
-                                               - $this_needed_to_discern_len);
-                $this_expected_len = $new_expected_len;
-                push @expected_malformation_return_flags, $::UTF8_GOT_LONG;
-                push @malformation_names, 'overlong';
-
-                if ($malformed_allow_type == 2) {
-                    $allow_flags |= $::UTF8_ALLOW_LONG_AND_ITS_VALUE;
-                }
-                elsif ($malformed_allow_type) {
-                    $allow_flags |= $::UTF8_ALLOW_LONG;
-                }
-            }
+              # If one of the other malformation types is also in effect, we
+              # don't know what the intended code point was.
+              if ($short || $unexpected_noncont || $will_overflow) {
+                  push @expected_malformation_warnings, qr/overlong/;
+              }
+              else {
+                  my $wrong_bytes = display_bytes_no_quotes(
+                                        substr($this_bytes, 0, $this_length));
+                  if (! defined $correct_bytes_for_overlong) {
+                      $correct_bytes_for_overlong
+                                          = display_bytes_no_quotes($bytes);
+                  }
+                  my $prefix = (   $allowed_uv > 0x10FFFF
+                                || ! isASCII && $allowed_uv < 256)
+                                ? "0x"
+                                : "U+";
+                  push @expected_malformation_warnings,
+                          qr/\QMalformed UTF-8 character: $wrong_bytes\E
+                              \Q (overlong; instead use\E
+                              \Q $correct_bytes_for_overlong to\E
+                              \Q represent $prefix$uv_string)/x;
+              }
 
-            if ($short) {
-                push @malformation_names, 'short';
+              if ($malformed_allow_type == 2) {
+                  $allow_flags |= $::UTF8_ALLOW_LONG_AND_ITS_VALUE;
+              }
+              elsif ($malformed_allow_type) {
+                  $allow_flags |= $::UTF8_ALLOW_LONG;
+              }
+          }
+          if ($short) {
+              push @malformation_names, 'short';
+              push @expected_malformation_return_flags, $::UTF8_GOT_SHORT;
+              push @expected_malformation_warnings, qr/too short/;
+          }
+          if ($unexpected_noncont) {
+              push @malformation_names, 'unexpected non-continuation';
+              push @expected_malformation_return_flags,
+                              $::UTF8_GOT_NON_CONTINUATION;
+              $allow_flags |= $::UTF8_ALLOW_NON_CONTINUATION
+                                                  if $malformed_allow_type;
+              push @expected_malformation_warnings,
+                                      qr/unexpected non-continuation byte/;
+          }
 
-                # To force this malformation, just tell the test to not look
-                # as far as it should into the input.
-                $this_length--;
-                $this_expected_len--;
-                push @expected_malformation_return_flags, $::UTF8_GOT_SHORT;
+          # The overflow malformation is done differently than other
+          # malformations.  It comes from manually typed tests in the test
+          # array.  We now make it be treated like one of the other
+          # malformations.  But some has to be deferred until the inner loop
+          my $overflow_msg_pattern;
+          if ($will_overflow) {
+              push @malformation_names, 'overflow';
+
+              $overflow_msg_pattern = display_bytes_no_quotes(
+                                  substr($this_bytes, 0, $this_expected_len));
+              $overflow_msg_pattern = qr/\QMalformed UTF-8 character:\E
+                                          \Q $overflow_msg_pattern\E
+                                          \Q (overflows)\E/x;
+              push @expected_malformation_return_flags, $::UTF8_GOT_OVERFLOW;
+              $allow_flags |= $::UTF8_ALLOW_OVERFLOW if $malformed_allow_type;
+          }
 
-                $allow_flags |= $::UTF8_ALLOW_SHORT if $malformed_allow_type;
-            }
+          # And we can create the malformation-related text for the the test
+          # names we eventually will generate.
+          my $malformations_name = "";
+          if (@malformation_names) {
+              $malformations_name .= "dis" unless $malformed_allow_type;
+              $malformations_name .= "allowed ";
+              $malformations_name .= "malformation";
+              $malformations_name .= "s" if @malformation_names > 1;
+              $malformations_name .= ": ";
+              $malformations_name .=  join "/", @malformation_names;
+              $malformations_name =  " ($malformations_name)";
+          }
 
-            if ($unexpected_noncont) {
-                push @malformation_names, 'unexpected non-continuation';
-
-                # To force this malformation, change the final continuation
-                # byte into a non continuation.
-                my $pos = ($short) ? -2 : -1;
-                substr($this_bytes, $pos, 1) = '?';
-                $this_expected_len--;
-                push @expected_malformation_return_flags,
-                                $::UTF8_GOT_NON_CONTINUATION;
-                $allow_flags |= $::UTF8_ALLOW_NON_CONTINUATION
-                                                    if $malformed_allow_type;
-            }
+          # Done setting up the malformation related stuff
 
-            # Here, we've transformed the input with all of the desired
-            # non-overflow malformations.  We are now in a position to
-            # construct any potential warnings for those malformations.  But
-            # it's a pain to get the detailed messages exactly right, so for
-            # now XXX, only do so for those that return an explicit code
-            # point.
+          {   # First test the isFOO calls
+              use warnings; # XXX no warnings 'deprecated';   # Make sure these don't raise warnings
+              undef @warnings_gotten;
 
-            if ($overlong) {
+              my $ret = test_isUTF8_CHAR($this_bytes, $this_length);
+              my $ret_flags
+                      = test_isUTF8_CHAR_flags($this_bytes, $this_length, 0);
+              if ($malformations_name) {
+                  is($ret, 0, "For $testname$malformations_name: isUTF8_CHAR() returns 0");
+                  is($ret_flags, 0, "    And isUTF8_CHAR_flags() returns 0");
+              }
+              else {
+                  is($ret, $this_length, "For $testname: isUTF8_CHAR() returns"
+                                        . " expected length: $this_length");
+                  is($ret_flags, $this_length,
+                      "    And isUTF8_CHAR_flags(...,0) returns expected"
+                    . " length: $this_length");
+              }
+              is(scalar @warnings_gotten, 0,
+                  "    And neither isUTF8_CHAR() nor isUTF8_CHAR()_flags"
+                . " generated any warnings")
+              or output_warnings(@warnings_gotten);
+
+              undef @warnings_gotten;
+              $ret = test_isSTRICT_UTF8_CHAR($this_bytes, $this_length);
+              if ($malformations_name) {
+                  is($ret, 0, "    And isSTRICT_UTF8_CHAR() returns 0");
+              }
+              else {
+                  my $expected_ret
+                              = (   $testname =~ /surrogate|non-character/
+                                  || $allowed_uv > 0x10FFFF)
+                                ? 0
+                                : $this_length;
+                  is($ret, $expected_ret,
+                      "    And isSTRICT_UTF8_CHAR() returns expected"
+                    . " length: $expected_ret");
+                  $ret = test_isUTF8_CHAR_flags($this_bytes, $this_length,
+                                      $::UTF8_DISALLOW_ILLEGAL_INTERCHANGE);
+                  is($ret, $expected_ret,
+                      "    And isUTF8_CHAR_flags('"
+                    . "DISALLOW_ILLEGAL_INTERCHANGE') acts like"
+                    . " isSTRICT_UTF8_CHAR");
+              }
+              is(scalar @warnings_gotten, 0,
+                      "    And neither isSTRICT_UTF8_CHAR() nor"
+                    . " isUTF8_CHAR_flags generated any warnings")
+              or output_warnings(@warnings_gotten);
+
+              undef @warnings_gotten;
+              $ret = test_isC9_STRICT_UTF8_CHAR($this_bytes, $this_length);
+              if ($malformations_name) {
+                  is($ret, 0, "    And isC9_STRICT_UTF8_CHAR() returns 0");
+              }
+              else {
+                  my $expected_ret = (   $testname =~ /surrogate/
+                                      || $allowed_uv > 0x10FFFF)
+                                      ? 0
+                                      : $this_expected_len;
+                  is($ret, $expected_ret, "    And isC9_STRICT_UTF8_CHAR()"
+                                        . " returns expected length:"
+                                        . " $expected_ret");
+                  $ret = test_isUTF8_CHAR_flags($this_bytes, $this_length,
+                                  $::UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE);
+                  is($ret, $expected_ret,
+                      "    And isUTF8_CHAR_flags('"
+                    . "DISALLOW_ILLEGAL_C9_INTERCHANGE') acts like"
+                    . " isC9_STRICT_UTF8_CHAR");
+              }
+              is(scalar @warnings_gotten, 0,
+                      "    And neither isC9_STRICT_UTF8_CHAR() nor"
+                    . " isUTF8_CHAR_flags generated any warnings")
+              or output_warnings(@warnings_gotten);
+
+              foreach my $disallow_type (0..2) {
+                  # 0 is don't disallow this type of code point
+                  # 1 is do disallow
+                  # 2 is do disallow, but only code points requiring
+                  #   perl-extended-UTF8
+
+                  my $disallow_flags;
+                  my $expected_ret;
+
+                  if ($malformations_name) {
+
+                      # Malformations are by default disallowed, so testing
+                      # with $disallow_type equal to 0 is sufficicient.
+                      next if $disallow_type;
+
+                      $disallow_flags = 0;
+                      $expected_ret = 0;
+                  }
+                  elsif ($disallow_type == 1) {
+                      $disallow_flags = $utf8n_flag_to_disallow;
+                      $expected_ret = 0;
+                  }
+                  elsif ($disallow_type == 2) {
+                      next if ! requires_extended_utf8($allowed_uv);
+                      $disallow_flags = $::UTF8_DISALLOW_PERL_EXTENDED;
+                      $expected_ret = 0;
+                  }
+                  else {  # type is 0
+                      $disallow_flags = $utf8n_flag_to_disallow_complement;
+                      $expected_ret = $this_length;
+                  }
+
+                  $ret = test_isUTF8_CHAR_flags($this_bytes, $this_length,
+                                                $disallow_flags);
+                  is($ret, $expected_ret,
+                            "    And isUTF8_CHAR_flags($display_bytes,"
+                          . " $disallow_flags) returns $expected_ret")
+                    or diag "The flags mean "
+                          . flags_to_text($disallow_flags,
+                                          \@utf8n_flags_to_text);
+                  is(scalar @warnings_gotten, 0,
+                          "    And isUTF8_CHAR_flags(...) generated"
+                        . " no warnings")
+                    or output_warnings(@warnings_gotten);
 
-                # If one of the other malformation types is also in effect, we
-                # don't know what the intended code point was.
-                if ($short || $unexpected_noncont || $will_overflow) {
-                    push @expected_malformation_warnings, qr/overlong/;
-                }
-                else {
-                    my $wrong_bytes = display_bytes_no_quotes(
-                                         substr($this_bytes, 0, $this_length));
-                    my $correct_bytes = display_bytes_no_quotes($bytes);
-                    my $prefix = ($allowed_uv > 0x10FFFF) ? "0x" : "U+";
-                    push @expected_malformation_warnings,
-                            qr/\QMalformed UTF-8 character: $wrong_bytes\E
-                               \Q (overlong; instead use\E
-                               \Q $correct_bytes to\E
-                               \Q represent $prefix$uv_string)/x;
-                }
-            }
-            if ($short) {
-                push @expected_malformation_warnings, qr/too short/;
-            }
-            if ($unexpected_noncont) {
-                push @expected_malformation_warnings,
-                                        qr/unexpected non-continuation byte/;
-            }
+                  # Test partial character handling, for each byte not a
+                  # full character
+                  my $did_test_partial = 0;
+                  for (my $j = 1; $j < $this_length - 1; $j++) {
+                      $did_test_partial = 1;
+                      my $partial = substr($this_bytes, 0, $j);
+                      my $ret_should_be;
+                      my $comment;
+                      if ($disallow_type || $malformations_name) {
+                          $ret_should_be = 0;
+                          $comment = "disallowed";
+
+                          # The number of bytes required to tell if a
+                          # sequence has something wrong is the smallest of
+                          # all the things wrong with it.  We start with the
+                          # number for this type of code point, if that is
+                          # disallowed; or the whole length if not.  The
+                          # latter is what a couple of the malformations
+                          # require.
+                          my $needed_to_tell = ($disallow_type)
+                                                ? $this_needed_to_discern_len
+                                                : $this_expected_len;
+
+                          # Then we see if the malformations that are
+                          # detectable early in the string are present.
+                          if ($overlong) {
+                              my $dl = overlong_discern_len($this_bytes);
+                              $needed_to_tell = $dl if $dl < $needed_to_tell;
+                          }
+                          if ($will_overflow) {
+                              my $dl = overflow_discern_len($length);
+                              $needed_to_tell = $dl if $dl < $needed_to_tell;
+                          }
+
+                          if ($j < $needed_to_tell) {
+                              $ret_should_be = 1;
+                              $comment .= ", but need $needed_to_tell"
+                                        . " bytes to discern:";
+                          }
+                      }
+                      else {
+                          $ret_should_be = 1;
+                          $comment = "allowed";
+                      }
+
+                      undef @warnings_gotten;
+
+                      $ret = test_is_utf8_valid_partial_char_flags($partial,
+                                                      $j, $disallow_flags);
+                      is($ret, $ret_should_be,
+                          "    And is_utf8_valid_partial_char_flags("
+                          . display_bytes($partial)
+                          . ", $disallow_flags), $comment: returns"
+                          . " $ret_should_be")
+                      or diag "The flags mean "
+                      . flags_to_text($disallow_flags, \@utf8n_flags_to_text);
+                  }
+
+                  if ($did_test_partial) {
+                      is(scalar @warnings_gotten, 0,
+                          "    And is_utf8_valid_partial_char_flags()"
+                          . " generated no warnings for any of the lengths")
+                        or output_warnings(@warnings_gotten);
+                  }
+              }
+          }
 
-            # The overflow malformation is done differently than other
-            # malformations.  It comes from manually typed tests in the test
-            # array.  We now make it be treated like one of the other
-            # malformations.  But some has to be deferred until the inner loop
-            my $overflow_msg_pattern;
-            if ($will_overflow) {
-                push @malformation_names, 'overflow';
+          # Now test the to/from UTF-8 calls.  There are several orthogonal
+          # variables involved.  We test most possible combinations
 
-                $overflow_msg_pattern = display_bytes_no_quotes(
-                                    substr($this_bytes, 0, $this_expected_len));
-                $overflow_msg_pattern = qr/\QMalformed UTF-8 character:\E
-                                           \Q $overflow_msg_pattern\E
-                                           \Q (overflows)\E/x;
-                push @expected_malformation_return_flags, $::UTF8_GOT_OVERFLOW;
-                $allow_flags |= $::UTF8_ALLOW_OVERFLOW if $malformed_allow_type;
+          foreach my $do_disallow (0, 1) {
+            if ($do_disallow) {
+              next if $initially_overlong || $initially_orphan;
             }
-
-            # And we can create the malformation-related text for the the test
-            # names we eventually will generate.
-            my $malformations_name = "";
-            if (@malformation_names) {
-                $malformations_name .= "dis" unless $malformed_allow_type;
-                $malformations_name .= "allowed ";
-                $malformations_name .= "malformation";
-                $malformations_name .= "s" if @malformation_names > 1;
-                $malformations_name .= ": ";
-                $malformations_name .=  join "/", @malformation_names;
-                $malformations_name =  " ($malformations_name)";
+            else {
+              next if $skip_most_tests;
             }
 
-            # Done setting up the malformation related stuff
-
-            foreach my $do_disallow (0, 1) {
-              next if $skip_most_tests && ! $do_disallow;
+            # This tests three functions.  utf8n_to_uvchr_error,
+            # utf8n_to_uvchr_msgs, and uvchr_to_utf8_flags.  But only the
+            # first two are variants of each other.  We use a loop
+            # 'which_func' to determine which of these.  uvchr_to_utf8_flags
+            # is done separately at the end of each iteration, only when
+            # which_func is 0.  which_func is numeric in part so we don't
+            # have to type in the function name and risk misspelling it
+            # somewhere, and also it sets whether we are expecting warnings
+            # or not in certain places.  The _msgs() version of the function
+            # expects warnings even if lexical ones are turned off, so by
+            # making its which_func == 1, we can say we want warnings;
+            # whereas the other one with the value 0, doesn't get them.
+            for my $which_func (0, 1) {
+              my $func = ($which_func)
+                          ? 'utf8n_to_uvchr_msgs'
+                          : 'utf8n_to_uvchr_error';
 
               # We classify the warnings into certain "interesting" types,
               # described later
               foreach my $warning_type (0..4) {
                 next if $skip_most_tests && $warning_type != 1;
                 foreach my $use_warn_flag (0, 1) {
-                    next if $skip_most_tests && ! $use_warn_flag;
+                    if ($use_warn_flag) {
+                        next if $initially_overlong || $initially_orphan;
+
+                        # Since utf8n_to_uvchr_msgs() expects warnings even
+                        # when lexical ones are turned off, we can skip
+                        # testing it when they are turned on, with little
+                        # likelihood of missing an error case.
+                        next if $which_func;
+                    }
+                    else {
+                        next if $skip_most_tests;
+                    }
 
                     # Finally, here is the inner loop
 
@@ -1070,7 +1401,7 @@ foreach my $test (@tests) {
                     my $expect_warnings_for_overflow;
 
                     if ($warning_type == 0) {
-                        $eval_warn = "use warnings; no warnings 'deprecated'";
+                        $eval_warn = "use warnings";
                         $expect_regular_warnings = $use_warn_flag;
 
                         # We ordinarily expect overflow warnings here.  But it
@@ -1086,9 +1417,9 @@ foreach my $test (@tests) {
                     }
                     elsif ($warning_type == 1) {
                         $eval_warn = "no warnings";
-                        $expect_regular_warnings = 0;
-                        $expect_warnings_for_overflow = 0;
-                        $expect_warnings_for_malformed = 0;
+                        $expect_regular_warnings = $which_func;
+                        $expect_warnings_for_overflow = $which_func;
+                        $expect_warnings_for_malformed = $which_func;
                     }
                     elsif ($warning_type == 2) {
                         $eval_warn = "no warnings; use warnings 'utf8'";
@@ -1103,29 +1434,30 @@ foreach my $test (@tests) {
                         $expect_regular_warnings = $use_warn_flag;
                         $expect_warnings_for_overflow
                             = $controlling_warning_category eq 'non_unicode';
-                        $expect_warnings_for_malformed = 0;
+                        $expect_warnings_for_malformed = $which_func;
                     }
                     elsif ($warning_type == 4) {  # Like type 3, but uses the
-                                                  # above-31-bit flags
+                                                  # PERL_EXTENDED flags
                         # The complement flags were set up so that the
-                        # above-31-bit flags have been tested that they don't
+                        # PERL_EXTENDED flags have been tested that they don't
                         # trigger wrongly for too small code points.  And the
                         # flags have been set up so that those small code
                         # points are tested for being above Unicode.  What's
                         # left to test is that the large code points do
-                        # trigger the above-31-bit flags.
+                        # trigger the PERL_EXTENDED flags.
                         next if ! requires_extended_utf8($allowed_uv);
                         next if $controlling_warning_category ne 'non_unicode';
                         $eval_warn = "no warnings; use warnings 'non_unicode'";
                         $expect_regular_warnings = 1;
                         $expect_warnings_for_overflow = 1;
                         $expect_warnings_for_malformed = 0;
-                        $this_utf8n_flag_to_warn   = $::UTF8_WARN_ABOVE_31_BIT;
+                        $this_utf8n_flag_to_warn = $::UTF8_WARN_PERL_EXTENDED;
                         $this_utf8n_flag_to_disallow
-                                                = $::UTF8_DISALLOW_ABOVE_31_BIT;
-                        $this_uvchr_flag_to_warn = $::UNICODE_WARN_ABOVE_31_BIT;
+                                             = $::UTF8_DISALLOW_PERL_EXTENDED;
+                        $this_uvchr_flag_to_warn
+                                              = $::UNICODE_WARN_PERL_EXTENDED;
                         $this_uvchr_flag_to_disallow
-                                             = $::UNICODE_DISALLOW_ABOVE_31_BIT;
+                                          = $::UNICODE_DISALLOW_PERL_EXTENDED;
                     }
                     else {
                        die "Unexpected warning type '$warning_type'";
@@ -1149,12 +1481,20 @@ foreach my $test (@tests) {
                     # on all the other flags.  That makes sure that they all
                     # are independent of this flag, and so we don't need to
                     # test them individually.
-                    my $this_warning_flags  = ($use_warn_flag)
-                                              ? $this_utf8n_flag_to_warn
-                                              : $utf8n_flag_to_warn_complement;
-                    my $this_disallow_flags = ($do_disallow)
-                                          ? $this_utf8n_flag_to_disallow
-                                          : $utf8n_flag_to_disallow_complement;
+                    my $this_warning_flags
+                            = ($use_warn_flag)
+                              ? $this_utf8n_flag_to_warn
+                              : ($overlong_is_in_perl_extended_utf8
+                                ? ($utf8n_flag_to_warn_complement
+                                    & ~$::UTF8_WARN_PERL_EXTENDED)
+                                :  $utf8n_flag_to_warn_complement);
+                    my $this_disallow_flags
+                            = ($do_disallow)
+                              ? $this_utf8n_flag_to_disallow
+                              : ($overlong_is_in_perl_extended_utf8
+                                 ? ($utf8n_flag_to_disallow_complement
+                                    & ~$::UTF8_DISALLOW_PERL_EXTENDED)
+                                 :  $utf8n_flag_to_disallow_complement);
                     my $expected_uv = $allowed_uv;
                     my $this_uv_string = $uv_string;
 
@@ -1180,14 +1520,14 @@ foreach my $test (@tests) {
                         # should emit a message or not.  It's tentative
                         # because, even if we ordinarily would output it, we
                         # don't if malformations are allowed -- except an
-                        # overflow is also a SUPER and ABOVE_31_BIT, and if
+                        # overflow is also a SUPER and PERL_EXTENDED, and if
                         # warnings for those are enabled, the overflow
                         # warning does get raised.
                         if (   $expect_warnings_for_overflow
                             && (    $malformed_allow_type == 0
                                 ||   (   $this_warning_flags
                                       & ($::UTF8_WARN_SUPER
-                                        |$::UTF8_WARN_ABOVE_31_BIT))))
+                                        |$::UTF8_WARN_PERL_EXTENDED))))
                         {
                             push @expected_warnings, $overflow_msg_pattern;
                         }
@@ -1213,19 +1553,21 @@ foreach my $test (@tests) {
 
                         # So far the array contains warnings generated by
                         # malformations.  Add the expected regular one.
-                        unshift @expected_warnings, $cp_message_qr;
+                        unshift @expected_warnings, $this_cp_message_qr;
 
                         # But it may need to be modified, because either of
                         # these malformations means we can't determine the
                         # expected code point.
-                        if ($short || $unexpected_noncont) {
+                        if (   $short || $unexpected_noncont
+                            || $dont_use_overlong_cp)
+                        {
                             my $first_byte = substr($this_bytes, 0, 1);
                             $expected_warnings[0] = display_bytes(
                                     substr($this_bytes, 0, $this_expected_len));
                             $expected_warnings[0]
                                 = qr/[Aa]\Qny UTF-8 sequence that starts with\E
                                      \Q $expected_warnings[0]\E
-                                     \Q $non_cp_trailing_text\E/x;
+                                     \Q $this_non_cp_trailing_text\E/x;
                         }
                     }
 
@@ -1252,11 +1594,14 @@ foreach my $test (@tests) {
                         }
                     }
 
-                    my $this_name = "utf8n_to_uvchr_error() $testname: "
-                                                . (($disallowed)
-                                                   ? 'disallowed'
-                                                   : 'allowed');
-                    $this_name .= ", $eval_warn";
+                    my $this_name = "$func() $testname: ";
+                    my @scratch_expected_return_flags = @expected_return_flags;
+                    if (! $initially_malformed) {
+                        $this_name .= ($disallowed)
+                                       ? 'disallowed, '
+                                       : 'allowed, ';
+                    }
+                    $this_name .= "$eval_warn";
                     $this_name .= ", " . ((  $this_warning_flags
                                             & $this_utf8n_flag_to_warn)
                                           ? 'with flag for raising warnings'
@@ -1269,15 +1614,16 @@ foreach my $test (@tests) {
                     my $this_flags
                         = $allow_flags|$this_warning_flags|$this_disallow_flags;
                     my $eval_text =      "$eval_warn; \$ret_ref"
-                            . " = test_utf8n_to_uvchr_error("
+                            . " = test_$func("
                             . "'$this_bytes', $this_length, $this_flags)";
                     eval "$eval_text";
-                    if (! ok ("$@ eq ''", "$this_name: eval succeeded"))
+                    if (! ok ($@ eq "", "$this_name: eval succeeded"))
                     {
                         diag "\$@='$@'; call was: "
                            . utf8n_display_call($eval_text);
                         next;
                     }
+
                     if ($disallowed) {
                         is($ret_ref->[0], 0, "    And returns 0")
                           or diag "Call was: " . utf8n_display_call($eval_text);
@@ -1295,47 +1641,95 @@ foreach my $test (@tests) {
 
                     my $returned_flags = $ret_ref->[2];
 
-                    for (my $i = @expected_return_flags - 1; $i >= 0; $i--) {
-                        if ($expected_return_flags[$i] & $returned_flags) {
-                            if ($expected_return_flags[$i]
-                                            == $::UTF8_DISALLOW_ABOVE_31_BIT)
-                            {
-                                pass("    Expected and got return flag for"
-                                   . " above_31_bit");
-                            }
-                                   # The first entries in this are
-                                   # malformations
-                            elsif ($i > @malformation_names - 1)  {
-                                pass("    Expected and got return flag"
-                                   . " for " . $controlling_warning_category);
-                            }
-                            else {
-                                pass("    Expected and got return flag for "
-                                   . $malformation_names[$i]
-                                   . " malformation");
-                            }
-                            $returned_flags &= ~$expected_return_flags[$i];
-                            splice @expected_return_flags, $i, 1;
-                        }
+                    for (my $i = @scratch_expected_return_flags - 1;
+                         $i >= 0;
+                         $i--)
+                    {
+                      if ($scratch_expected_return_flags[$i] & $returned_flags)
+                      {
+                          if ($scratch_expected_return_flags[$i]
+                                              == $::UTF8_GOT_PERL_EXTENDED)
+                          {
+                              pass("    Expected and got return flag for"
+                                  . " PERL_EXTENDED");
+                          }
+                                  # The first entries in this are
+                                  # malformations
+                          elsif ($i > @malformation_names - 1)  {
+                              pass("    Expected and got return flag"
+                                  . " for " . $controlling_warning_category);
+                          }
+                          else {
+                              pass("    Expected and got return flag for "
+                                  . $malformation_names[$i]
+                                  . " malformation");
+                          }
+                          $returned_flags
+                                      &= ~$scratch_expected_return_flags[$i];
+                          splice @scratch_expected_return_flags, $i, 1;
+                      }
                     }
 
-                    is($returned_flags, 0,
-                       "    Got no unexpected return flags")
-                      or diag "The unexpected flags gotten were: "
+                    if (! is($returned_flags, 0,
+                       "    Got no unexpected return flags"))
+                    {
+                        diag "The unexpected flags gotten were: "
                            . (flags_to_text($returned_flags,
                                             \@utf8n_flags_to_text)
                                 # We strip off any prefixes from the flag
                                 # names
                              =~ s/ \b [A-Z] _ //xgr);
-                    is (scalar @expected_return_flags, 0,
-                        "    Got all expected return flags")
-                        or diag "The expected flags not gotten were: "
+                        diag "Call was: " . utf8n_display_call($eval_text);
+                    }
+
+                    if (! is (scalar @scratch_expected_return_flags, 0,
+                        "    Got all expected return flags"))
+                    {
+                        diag "The expected flags not gotten were: "
                            . (flags_to_text(eval join("|",
-                                                        @expected_return_flags),
+                                                @scratch_expected_return_flags),
                                             \@utf8n_flags_to_text)
                                 # We strip off any prefixes from the flag
                                 # names
                              =~ s/ \b [A-Z] _ //xgr);
+                        diag "Call was: " . utf8n_display_call($eval_text);
+                    }
+
+                    if ($which_func) {
+                        my @returned_warnings;
+                        for my $element_ref (@{$ret_ref->[3]}) {
+                            push @returned_warnings, $element_ref->{'text'};
+                            my $text = $element_ref->{'text'};
+                            my $flag = $element_ref->{'flag_bit'};
+                            my $category = $element_ref->{'warning_category'};
+
+                            if (! ok(($flag & ($flag-1)) == 0,
+                                      "flag for returned msg is a single bit"))
+                            {
+                              diag sprintf("flags are %x; msg=%s", $flag, $text);
+                            }
+                            else {
+                              if (grep { $_ == $flag } @expected_return_flags) {
+                                  pass("flag for returned msg is expected");
+                              }
+                              else {
+                                  fail("flag for returned msg is expected: "
+                                 . flags_to_text($flag, \@utf8n_flags_to_text));
+                              }
+                            }
+
+                            # In perl space, don't know the category numbers
+                            isnt($category, 0,
+                                          "returned category for msg isn't 0");
+                        }
+
+                        ok(@warnings_gotten == 0, "$func raised no warnings;"
+                              . " the next tests are for ones in the returned"
+                              . " variable")
+                            or diag join "\n", "The unexpected warnings were:",
+                                                              @warnings_gotten;
+                        @warnings_gotten = @returned_warnings;
+                    }
 
                     do_warnings_test(@expected_warnings)
                       or diag "Call was: " . utf8n_display_call($eval_text);
@@ -1343,15 +1737,19 @@ foreach my $test (@tests) {
 
                     # Check CHECK_ONLY results when the input is
                     # disallowed.  Do this when actually disallowed,
-                    # not just when the $this_disallow_flags is set
-                    if ($disallowed) {
+                    # not just when the $this_disallow_flags is set.  We only
+                    # test once utf8n_to_uvchr_msgs() with this.
+                    if (   $disallowed
+                        && ($which_func == 0 || ! $tested_CHECK_ONLY))
+                    {
+                        $tested_CHECK_ONLY = 1;
                         my $this_flags = $this_disallow_flags|$::UTF8_CHECK_ONLY;
-                        my $eval_text = "use warnings; no warnings 'deprecated'; \$ret_ref ="
-                                      . " test_utf8n_to_uvchr_error('"
+                        my $eval_text = "use warnings; \$ret_ref ="
+                                      . " test_$func('"
                                       . "$this_bytes', $this_length,"
                                       . " $this_flags)";
                         eval $eval_text;
-                        if (! ok ("$@ eq ''",
+                        if (! ok ($@ eq "",
                             "    And eval succeeded with CHECK_ONLY"))
                         {
                             diag "\$@='$@'; Call was: "
@@ -1376,6 +1774,7 @@ foreach my $test (@tests) {
                     # existing code point, it hasn't overflowed, and isn't
                     # malformed.
                     next if @malformation_names;
+                    next if $which_func;
 
                     $this_warning_flags = ($use_warn_flag)
                                           ? $this_uvchr_flag_to_warn
@@ -1408,7 +1807,7 @@ foreach my $test (@tests) {
                             . " test_uvchr_to_utf8_flags("
                             . "$allowed_uv, $this_flags)";
                     eval "$eval_text";
-                    if (! ok ("$@ eq ''", "$this_name: eval succeeded"))
+                    if (! ok ($@ eq "", "$this_name: eval succeeded"))
                     {
                         diag "\$@='$@'; call was: "
                            . uvchr_display_call($eval_text);
@@ -1432,6 +1831,7 @@ foreach my $test (@tests) {
         }
       }
     }
+  }
 }
 
 done_testing;