From 0b735a0ee01c105cf8ccedca77382e4eb7dad74e Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Tue, 5 Feb 2019 15:59:59 +1100
Subject: (perl #133822) check strictness on split bareword

Perl_ck_split was converting the OP_CONST into a PM without
checking the strictness flag.
---
 op.c           |  2 ++
 t/lib/croak/op | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/op.c b/op.c
index 8a61b8b616..c33e6f6f5e 100644
--- a/op.c
+++ b/op.c
@@ -12834,6 +12834,8 @@ Perl_ck_split(pTHX_ OP *o)
     kid = cLISTOPo->op_first;
 
     if (kid->op_type != OP_MATCH || kid->op_flags & OPf_STACKED) {
+        if (kid->op_type == OP_CONST && (kid->op_private & OPpCONST_STRICT))
+            no_bareword_allowed(kid);
         /* remove match expression, and replace with new optree with
          * a match op at its head */
         op_sibling_splice(o, NULL, 1, NULL);
diff --git a/t/lib/croak/op b/t/lib/croak/op
index 5f31478860..4ad74f31c3 100644
--- a/t/lib/croak/op
+++ b/t/lib/croak/op
@@ -251,3 +251,13 @@ Type of arg 1 to pop must be array (not private hash) at - line 4, near "%a;"
 Type of arg 1 to shift must be array (not private hash) at - line 5, near "%a;"
 Type of arg 1 to unshift must be array (not private hash) at - line 6, near "1;"
 Execution of - aborted due to compilation errors.
+########
+# NAME split bareword
+use strict;
+my $x = "";
+my @x = split bareword, $x;
+my @x = split +bareword, $x;
+EXPECT
+Bareword "bareword" not allowed while "strict subs" in use at - line 3.
+Bareword "bareword" not allowed while "strict subs" in use at - line 4.
+Execution of - aborted due to compilation errors.
-- 
2.11.0

From 61135e4bdbcc08b4d0a342740ec9b24aff273dd5 Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Tue, 5 Feb 2019 15:59:59 +1100
Subject: (perl #133822) deprecate split bareword

---
 op.c                    |  4 ++++
 pod/perldeprecation.pod | 10 ++++++++++
 pod/perldiag.pod        |  6 ++++++
 t/lib/warnings/op       |  9 +++++++++
 4 files changed, 29 insertions(+)

diff --git a/op.c b/op.c
index 86251047b6..b133e3964e 100644
--- a/op.c
+++ b/op.c
@@ -13242,6 +13242,10 @@ Perl_ck_split(pTHX_ OP *o)
     kid = cLISTOPo->op_first;
 
     if (kid->op_type != OP_MATCH || kid->op_flags & OPf_STACKED) {
+        if (kid->op_type == OP_CONST && (kid->op_private & OPpCONST_STRICT)) {
+            Perl_ck_warner_d(aTHX_ packWARN(WARN_DEPRECATED),
+                             "Bareword pattern for split() under strict \"subs\" deprecated");
+        }
         /* remove match expression, and replace with new optree with
          * a match op at its head */
         op_sibling_splice(o, NULL, 1, NULL);
diff --git a/pod/perldeprecation.pod b/pod/perldeprecation.pod
index c96be0c671..6ce9c78d8b 100644
--- a/pod/perldeprecation.pod
+++ b/pod/perldeprecation.pod
@@ -14,6 +14,16 @@ features are available.
 The deprecated features will be grouped by the version of Perl in
 which they will be removed.
 
+=head2 Perl 5.36
+
+=head3 Bareword pattern for split() under strict "subs"
+
+The L<perlfunc/split> operator currently allows (with a deprecation
+warning) a bareword as the first argument to split.  This will become
+an error in Perl 5.36.
+
+See L<https://rt.perl.org/Ticket/Display.html?id=133822> for details.
+
 =head2 Perl 5.32
 
 =head3 Constants from lexical variables potentially modified elsewhere
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 2fa4b62257..b52469d7fc 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -557,6 +557,12 @@ double-colon.  Write C<require ::Foo::Bar> as  C<require Foo::Bar> instead.
 subroutine identifier, in curly brackets or to the left of the "=>"
 symbol.  Perhaps you need to predeclare a subroutine?
 
+=item Bareword pattern for split() under strict "subs" deprecated
+
+(D deprecated) Perl has erroneously long allowed a bareword as the
+PATTERN argyment to L<perlfunc/split>.  This will be disallowed in
+perl 5.36.
+
 =item Bareword "%s" refers to nonexistent package
 
 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
diff --git a/t/lib/warnings/op b/t/lib/warnings/op
index 4d0b002a15..3314d21384 100644
--- a/t/lib/warnings/op
+++ b/t/lib/warnings/op
@@ -2063,3 +2063,12 @@ Useless use of a constant (32) in void context at - line 11.
 Useless use of a constant (41) in void context at - line 14.
 Useless use of a constant (42) in void context at - line 14.
 Useless use of a constant (51) in void context at - line 16.
+########
+# NAME split bareword
+use strict;
+my $x = "";
+my @x = split bareword, $x;
+my @x = split +bareword, $x;
+EXPECT
+Bareword pattern for split() under strict "subs" deprecated - line 3.
+Bareword pattern for split() under strict "subs" deprecated - line 4.
-- 
2.11.0