Move substr tests under t/op

Commit a4499558 moved them under t/re along with the subst tests, but
these are unrelated to regexps.

1 files changed, 764 insertions, 0 deletions

diff --git a/t/op/substr.t b/t/op/substr.t
new file mode 100644
index 0000000000..e9ea12693a
--- /dev/null
+++ b/t/op/substr.t
@@ -0,0 +1,764 @@
+#!./perl
+
+#P = start of string  Q = start of substr  R = end of substr  S = end of string
+
+BEGIN {
+    chdir 't' if -d 't';
+    @INC = '../lib';
+}
+use warnings ;
+no warnings 'deprecated';
+
+$a = 'abcdefxyz';
+$SIG{__WARN__} = sub {
+     if ($_[0] =~ /^substr outside of string/) {
+          $w++;
+     } elsif ($_[0] =~ /^Attempt to use reference as lvalue in substr/) {
+          $w += 2;
+     } elsif ($_[0] =~ /^Use of uninitialized value/) {
+          $w += 3;
+     } else {
+          warn $_[0];
+     }
+};
+
+BEGIN { require './test.pl'; }
+
+plan(358);
+
+run_tests() unless caller;
+
+my $krunch = "a";
+
+sub run_tests {
+
+$FATAL_MSG = qr/^substr outside of string/;
+
+is(substr($a,0,3), 'abc');   # P=Q R S
+is(substr($a,3,3), 'def');   # P Q R S
+is(substr($a,6,999), 'xyz'); # P Q S R
+$b = substr($a,999,999) ; # warn # P R Q S
+is ($w--, 1);
+eval{substr($a,999,999) = "" ; };# P R Q S
+like ($@, $FATAL_MSG);
+is(substr($a,0,-6), 'abc');  # P=Q R S
+is(substr($a,-3,1), 'x');    # P Q R S
+
+substr($a,3,3) = 'XYZ';
+is($a, 'abcXYZxyz' );
+substr($a,0,2) = '';
+is($a, 'cXYZxyz' );
+substr($a,0,0) = 'ab';
+is($a, 'abcXYZxyz' );
+substr($a,0,0) = '12345678';
+is($a, '12345678abcXYZxyz' );
+substr($a,-3,3) = 'def';
+is($a, '12345678abcXYZdef');
+substr($a,-3,3) = '<';
+is($a, '12345678abcXYZ<' );
+substr($a,-1,1) = '12345678';
+is($a, '12345678abcXYZ12345678' );
+
+$a = 'abcdefxyz';
+
+is(substr($a,6), 'xyz' );        # P Q R=S
+is(substr($a,-3), 'xyz' );       # P Q R=S
+$b = substr($a,999,999) ; # warning   # P R=S Q
+is($w--, 1);
+eval{substr($a,999,999) = "" ; } ;    # P R=S Q
+like($@, $FATAL_MSG);
+is(substr($a,0), 'abcdefxyz');  # P=Q R=S
+is(substr($a,9), '');           # P Q=R=S
+is(substr($a,-11), 'abcdefxyz'); # Q P R=S
+is(substr($a,-9), 'abcdefxyz');  # P=Q R=S
+
+$a = '54321';
+
+$b = substr($a,-7, 1) ; # warn  # Q R P S
+is($w--, 1);
+eval{substr($a,-7, 1) = "" ; }; # Q R P S
+like($@, $FATAL_MSG);
+$b = substr($a,-7,-6) ; # warn  # Q R P S
+is($w--, 1);
+eval{substr($a,-7,-6) = "" ; }; # Q R P S
+like($@, $FATAL_MSG);
+is(substr($a,-5,-7), '');  # R P=Q S
+is(substr($a, 2,-7), '');  # R P Q S
+is(substr($a,-3,-7), '');  # R P Q S
+is(substr($a, 2,-5), '');  # P=R Q S
+is(substr($a,-3,-5), '');  # P=R Q S
+is(substr($a, 2,-4), '');  # P R Q S
+is(substr($a,-3,-4), '');  # P R Q S
+is(substr($a, 5,-6), '');  # R P Q=S
+is(substr($a, 5,-5), '');  # P=R Q S
+is(substr($a, 5,-3), '');  # P R Q=S
+$b = substr($a, 7,-7) ; # warn  # R P S Q
+is($w--, 1);
+eval{substr($a, 7,-7) = "" ; }; # R P S Q
+like($@, $FATAL_MSG);
+$b = substr($a, 7,-5) ; # warn  # P=R S Q
+is($w--, 1);
+eval{substr($a, 7,-5) = "" ; }; # P=R S Q
+like($@, $FATAL_MSG);
+$b = substr($a, 7,-3) ; # warn  # P Q S Q
+is($w--, 1);
+eval{substr($a, 7,-3) = "" ; }; # P Q S Q
+like($@, $FATAL_MSG);
+$b = substr($a, 7, 0) ; # warn  # P S Q=R
+is($w--, 1);
+eval{substr($a, 7, 0) = "" ; }; # P S Q=R
+like($@, $FATAL_MSG);
+
+is(substr($a,-7,2), '');   # Q P=R S
+is(substr($a,-7,4), '54'); # Q P R S
+is(substr($a,-7,7), '54321');# Q P R=S
+is(substr($a,-7,9), '54321');# Q P S R
+is(substr($a,-5,0), '');   # P=Q=R S
+is(substr($a,-5,3), '543');# P=Q R S
+is(substr($a,-5,5), '54321');# P=Q R=S
+is(substr($a,-5,7), '54321');# P=Q S R
+is(substr($a,-3,0), '');   # P Q=R S
+is(substr($a,-3,3), '321');# P Q R=S
+is(substr($a,-2,3), '21'); # P Q S R
+is(substr($a,0,-5), '');   # P=Q=R S
+is(substr($a,2,-3), '');   # P Q=R S
+is(substr($a,0,0), '');    # P=Q=R S
+is(substr($a,0,5), '54321');# P=Q R=S
+is(substr($a,0,7), '54321');# P=Q S R
+is(substr($a,2,0), '');    # P Q=R S
+is(substr($a,2,3), '321'); # P Q R=S
+is(substr($a,5,0), '');    # P Q=R=S
+is(substr($a,5,2), '');    # P Q=S R
+is(substr($a,-7,-5), '');  # Q P=R S
+is(substr($a,-7,-2), '543');# Q P R S
+is(substr($a,-5,-5), '');  # P=Q=R S
+is(substr($a,-5,-2), '543');# P=Q R S
+is(substr($a,-3,-3), '');  # P Q=R S
+is(substr($a,-3,-1), '32');# P Q R S
+
+$a = '';
+
+is(substr($a,-2,2), '');   # Q P=R=S
+is(substr($a,0,0), '');    # P=Q=R=S
+is(substr($a,0,1), '');    # P=Q=S R
+is(substr($a,-2,3), '');   # Q P=S R
+is(substr($a,-2), '');     # Q P=R=S
+is(substr($a,0), '');      # P=Q=R=S
+
+
+is(substr($a,0,-1), '');   # R P=Q=S
+$b = substr($a,-2, 0) ; # warn  # Q=R P=S
+is($w--, 1);
+eval{substr($a,-2, 0) = "" ; }; # Q=R P=S
+like($@, $FATAL_MSG);
+
+$b = substr($a,-2, 1) ; # warn  # Q R P=S
+is($w--, 1);
+eval{substr($a,-2, 1) = "" ; }; # Q R P=S
+like($@, $FATAL_MSG);
+
+$b = substr($a,-2,-1) ; # warn  # Q R P=S
+is($w--, 1);
+eval{substr($a,-2,-1) = "" ; }; # Q R P=S
+like($@, $FATAL_MSG);
+
+$b = substr($a,-2,-2) ; # warn  # Q=R P=S
+is($w--, 1);
+eval{substr($a,-2,-2) = "" ; }; # Q=R P=S
+like($@, $FATAL_MSG);
+
+$b = substr($a, 1,-2) ; # warn  # R P=S Q
+is($w--, 1);
+eval{substr($a, 1,-2) = "" ; }; # R P=S Q
+like($@, $FATAL_MSG);
+
+$b = substr($a, 1, 1) ; # warn  # P=S Q R
+is($w--, 1);
+eval{substr($a, 1, 1) = "" ; }; # P=S Q R
+like($@, $FATAL_MSG);
+
+$b = substr($a, 1, 0) ;# warn   # P=S Q=R
+is($w--, 1);
+eval{substr($a, 1, 0) = "" ; }; # P=S Q=R
+like($@, $FATAL_MSG);
+
+$b = substr($a,1) ; # warning   # P=R=S Q
+is($w--, 1);
+eval{substr($a,1) = "" ; };     # P=R=S Q
+like($@, $FATAL_MSG);
+
+$b = substr($a,-7,-6) ; # warn  # Q R P S
+is($w--, 1);
+eval{substr($a,-7,-6) = "" ; }; # Q R P S
+like($@, $FATAL_MSG);
+
+my $a = 'zxcvbnm';
+substr($a,2,0) = '';
+is($a, 'zxcvbnm');
+substr($a,7,0) = '';
+is($a, 'zxcvbnm');
+substr($a,5,0) = '';
+is($a, 'zxcvbnm');
+substr($a,0,2) = 'pq';
+is($a, 'pqcvbnm');
+substr($a,2,0) = 'r';
+is($a, 'pqrcvbnm');
+substr($a,8,0) = 'asd';
+is($a, 'pqrcvbnmasd');
+substr($a,0,2) = 'iop';
+is($a, 'ioprcvbnmasd');
+substr($a,0,5) = 'fgh';
+is($a, 'fghvbnmasd');
+substr($a,3,5) = 'jkl';
+is($a, 'fghjklsd');
+substr($a,3,2) = '1234';
+is($a, 'fgh1234lsd');
+
+
+# with lexicals (and in re-entered scopes)
+for (0,1) {
+  my $txt;
+  unless ($_) {
+    $txt = "Foo";
+    substr($txt, -1) = "X";
+    is($txt, "FoX");
+  }
+  else {
+    substr($txt, 0, 1) = "X";
+    is($txt, "X");
+  }
+}
+
+$w = 0 ;
+# coercion of references
+{
+  my $s = [];
+  substr($s, 0, 1) = 'Foo';
+  is (substr($s,0,7), "FooRRAY");
+  is ($w,2);
+  $w = 0;
+}
+
+# check no spurious warnings
+is($w, 0);
+
+# check new 4 arg replacement syntax
+$a = "abcxyz";
+$w = 0;
+is(substr($a, 0, 3, ""), "abc");
+is($a, "xyz");
+is(substr($a, 0, 0, "abc"), "");
+is($a, "abcxyz");
+is(substr($a, 3, -1, ""), "xy");
+is($a, "abcz");
+
+is(substr($a, 3, undef, "xy"), "");
+is($a, "abcxyz");
+is($w, 3);
+
+$w = 0;
+
+is(substr($a, 3, 9999999, ""), "xyz");
+is($a, "abc");
+eval{substr($a, -99, 0, "") };
+like($@, $FATAL_MSG);
+eval{substr($a, 99, 3, "") };
+like($@, $FATAL_MSG);
+
+substr($a, 0, length($a), "foo");
+is ($a, "foo");
+is ($w, 0);
+
+# using 4 arg substr as lvalue is a compile time error
+eval 'substr($a,0,0,"") = "abc"';
+like ($@, qr/Can't modify substr/);
+is ($a, "foo");
+
+$a = "abcdefgh";
+is(sub { shift }->(substr($a, 0, 4, "xxxx")), 'abcd');
+is($a, 'xxxxefgh');
+
+{
+    my $y = 10;
+    $y = "2" . $y;
+    is ($y, 210);
+}
+
+# utf8 sanity
+{
+    my $x = substr("a\x{263a}b",0);
+    is(length($x), 3);
+    $x = substr($x,1,1);
+    is($x, "\x{263a}");
+    $x = $x x 2;
+    is(length($x), 2);
+    substr($x,0,1) = "abcd";
+    is($x, "abcd\x{263a}");
+    is(length($x), 5);
+    $x = reverse $x;
+    is(length($x), 5);
+    is($x, "\x{263a}dcba");
+
+    my $z = 10;
+    $z = "21\x{263a}" . $z;
+    is(length($z), 5);
+    is($z, "21\x{263a}10");
+}
+
+# replacement should work on magical values
+require Tie::Scalar;
+my %data;
+tie $data{'a'}, 'Tie::StdScalar';  # makes $data{'a'} magical
+$data{a} = "firstlast";
+is(substr($data{'a'}, 0, 5, ""), "first");
+is($data{'a'}, "last");
+
+# more utf8
+
+# The following two originally from Ignasi Roca.
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, 1) = "\x{100}"; # Ignasi had \x{FF}
+is(length($x), 3);
+is($x, "\x{100}\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, 1) = "\x{100}\x{FF}"; # Ignasi had \x{FF}
+is(length($x), 4);
+is($x, "\x{100}\x{FF}\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F2}");
+is(substr($x, 3, 1), "\x{F3}");
+
+# more utf8 lval exercise
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, 2) = "\x{100}\xFF";
+is(length($x), 3);
+is($x, "\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 1, 1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\xF1\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{100}");
+is(substr($x, 2, 1), "\x{FF}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 2, 1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\xF1\xF2\x{100}\xFF");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 3, 1) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\xF1\xF2\xF3\x{100}\xFF");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{F3}");
+is(substr($x, 3, 1), "\x{100}");
+is(substr($x, 4, 1), "\x{FF}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, -1, 1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\xF1\xF2\x{100}\xFF");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, -1, 0) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\xF1\xF2\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+is(substr($x, 4, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, -1) = "\x{100}\xFF";
+is(length($x), 3);
+is($x, "\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, -2) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\x{100}\xFF\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F2}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, -3) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\x{100}\xFF\xF1\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F1}");
+is(substr($x, 3, 1), "\x{F2}");
+is(substr($x, 4, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, 1, -1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\xF1\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{100}");
+is(substr($x, 2, 1), "\x{FF}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\xF1\xF2\xF3";
+substr($x, -1, -1) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\xF1\xF2\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{F1}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+is(substr($x, 4, 1), "\x{F3}");
+
+# And tests for already-UTF8 one
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, 1) = "\x{100}";
+is(length($x), 3);
+is($x, "\x{100}\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, 1) = "\x{100}\x{FF}";
+is(length($x), 4);
+is($x, "\x{100}\x{FF}\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F2}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, 2) = "\x{100}\xFF";
+is(length($x), 3);
+is($x, "\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 1, 1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\x{101}\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{100}");
+is(substr($x, 2, 1), "\x{FF}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 2, 1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\x{101}\xF2\x{100}\xFF");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 3, 1) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\x{101}\x{F2}\x{F3}\x{100}\xFF");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{F3}");
+is(substr($x, 3, 1), "\x{100}");
+is(substr($x, 4, 1), "\x{FF}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, -1, 1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\x{101}\xF2\x{100}\xFF");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, -1, 0) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\x{101}\xF2\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+is(substr($x, 4, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, -1) = "\x{100}\xFF";
+is(length($x), 3);
+is($x, "\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, -2) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\x{100}\xFF\xF2\xF3");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{F2}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, -3) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\x{100}\xFF\x{101}\x{F2}\x{F3}");
+is(substr($x, 0, 1), "\x{100}");
+is(substr($x, 1, 1), "\x{FF}");
+is(substr($x, 2, 1), "\x{101}");
+is(substr($x, 3, 1), "\x{F2}");
+is(substr($x, 4, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 1, -1) = "\x{100}\xFF";
+is(length($x), 4);
+is($x, "\x{101}\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{100}");
+is(substr($x, 2, 1), "\x{FF}");
+is(substr($x, 3, 1), "\x{F3}");
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, -1, -1) = "\x{100}\xFF";
+is(length($x), 5);
+is($x, "\x{101}\xF2\x{100}\xFF\xF3");
+is(substr($x, 0, 1), "\x{101}");
+is(substr($x, 1, 1), "\x{F2}");
+is(substr($x, 2, 1), "\x{100}");
+is(substr($x, 3, 1), "\x{FF}");
+is(substr($x, 4, 1), "\x{F3}");
+
+substr($x = "ab", 0, 0, "\x{100}\x{200}");
+is($x, "\x{100}\x{200}ab");
+
+substr($x = "\x{100}\x{200}", 0, 0, "ab");
+is($x, "ab\x{100}\x{200}");
+
+substr($x = "ab", 1, 0, "\x{100}\x{200}");
+is($x, "a\x{100}\x{200}b");
+
+substr($x = "\x{100}\x{200}", 1, 0, "ab");
+is($x, "\x{100}ab\x{200}");
+
+substr($x = "ab", 2, 0, "\x{100}\x{200}");
+is($x, "ab\x{100}\x{200}");
+
+substr($x = "\x{100}\x{200}", 2, 0, "ab");
+is($x, "\x{100}\x{200}ab");
+
+substr($x = "\xFFb", 0, 0, "\x{100}\x{200}");
+is($x, "\x{100}\x{200}\xFFb");
+
+substr($x = "\x{100}\x{200}", 0, 0, "\xFFb");
+is($x, "\xFFb\x{100}\x{200}");
+
+substr($x = "\xFFb", 1, 0, "\x{100}\x{200}");
+is($x, "\xFF\x{100}\x{200}b");
+
+substr($x = "\x{100}\x{200}", 1, 0, "\xFFb");
+is($x, "\x{100}\xFFb\x{200}");
+
+substr($x = "\xFFb", 2, 0, "\x{100}\x{200}");
+is($x, "\xFFb\x{100}\x{200}");
+
+substr($x = "\x{100}\x{200}", 2, 0, "\xFFb");
+is($x, "\x{100}\x{200}\xFFb");
+
+# [perl #20933]
+{ 
+    my $s = "ab";
+    my @r; 
+    $r[$_] = \ substr $s, $_, 1 for (0, 1);
+    is(join("", map { $$_ } @r), "ab");
+}
+
+# [perl #23207]
+{
+    sub ss {
+	substr($_[0],0,1) ^= substr($_[0],1,1) ^=
+	substr($_[0],0,1) ^= substr($_[0],1,1);
+    }
+    my $x = my $y = 'AB'; ss $x; ss $y;
+    is($x, $y);
+}
+
+# [perl #24605]
+{
+    my $x = "0123456789\x{500}";
+    my $y = substr $x, 4;
+    is(substr($x, 7, 1), "7");
+}
+
+# multiple assignments to lvalue [perl #24346]   
+{
+    my $x = "abcdef";
+    for (substr($x,1,3)) {
+	is($_, 'bcd');
+	$_ = 'XX';
+	is($_, 'XX');
+	is($x, 'aXXef'); 
+	$_ = "\xFF";
+	is($_, "\xFF"); 
+	is($x, "a\xFFef");
+	$_ = "\xF1\xF2\xF3\xF4\xF5\xF6";
+	is($_, "\xF1\xF2\xF3\xF4\xF5\xF6");
+	is($x, "a\xF1\xF2\xF3\xF4\xF5\xF6ef"); 
+	$_ = 'YYYY';
+	is($_, 'YYYY'); 
+	is($x, 'aYYYYef');
+    }
+}
+
+# [perl #24200] string corruption with lvalue sub
+
+{
+    sub bar: lvalue { substr $krunch, 0 }
+    bar = "XXX";
+    is(bar, 'XXX');
+    $krunch = '123456789';
+    is(bar, '123456789');
+}
+
+# [perl #29149]
+{
+    my $text  = "0123456789\xED ";
+    utf8::upgrade($text);
+    my $pos = 5;
+    pos($text) = $pos;
+    my $a = substr($text, $pos, $pos);
+    is(substr($text,$pos,1), $pos);
+
+}
+
+# [perl #23765]
+{
+    my $a = pack("C", 0xbf);
+    substr($a, -1) &= chr(0xfeff);
+    is($a, "\xbf");
+}
+
+# [perl #34976] incorrect caching of utf8 substr length
+{
+    my  $a = "abcd\x{100}";
+    is(substr($a,1,2), 'bc');
+    is(substr($a,1,1), 'b');
+}
+
+# [perl #62646] offsets exceeding 32 bits on 64-bit system
+SKIP: {
+    skip("32-bit system", 24) unless ~0 > 0xffffffff;
+    my $a = "abc";
+    my $s;
+    my $r;
+
+    utf8::downgrade($a);
+    for (1..2) {
+	$w = 0;
+	$r = substr($a, 0xffffffff, 1);
+	is($r, undef);
+	is($w, 1);
+
+	$w = 0;
+	$r = substr($a, 0xffffffff+1, 1);
+	is($r, undef);
+	is($w, 1);
+
+	$w = 0;
+	ok( !eval { $r = substr($s=$a, 0xffffffff, 1, "_"); 1 } );
+	is($r, undef);
+	is($s, $a);
+	is($w, 0);
+
+	$w = 0;
+	ok( !eval { $r = substr($s=$a, 0xffffffff+1, 1, "_"); 1 } );
+	is($r, undef);
+	is($s, $a);
+	is($w, 0);
+
+	utf8::upgrade($a);
+    }
+}
+
+}
+
+
+my $destroyed;
+{ package Class; DESTROY { ++$destroyed; } }
+
+$destroyed = 0;
+{
+    my $x = '';
+    substr($x,0,1) = "";
+    $x = bless({}, 'Class');
+}
+is($destroyed, 1, 'Timely scalar destruction with lvalue substr');
+
+# [perl #77692] UTF8 cache not being reset when TARG is reused
+ok eval {
+ local ${^UTF8CACHE} = -1;
+ for my $i (0..1)
+ {
+   my $dummy = length(substr("\x{100}",0,$i));
+ }
+ 1
+}, 'UTF8 cache is reset when TARG is reused [perl #77692]';
+
+{
+    my $result_3363;
+    sub a_3363 {
+        my ($word, $replace) = @_;
+        my $ref = \substr($word, 0, 1);
+        $$ref = $replace;
+        if ($replace eq "b") {
+            $result_3363 = $word;
+        } else {
+            a_3363($word, "b");
+        }
+    }
+    a_3363($_, "v") for "test";
+
+    is($result_3363, "best", "ref-to-substr retains lvalue-ness under recursion [perl #3363]");
+}
+
+{
+    use utf8;
+    use open qw( :utf8 :std );
+    no warnings 'once';
+
+    my $t = "";
+    substr $t, 0, 0, *ワルド;
+    is($t, "*main::ワルド", "substr works on UTF-8 globs");
+
+    $t = "The World!";
+    substr $t, 0, 9, *ザ::ワルド;
+    is($t, "*ザ::ワルド!", "substr works on a UTF-8 glob + stash");
+}