From b2362f9ce4a402f311f6b7a96d97bbe9569e2f54 Mon Sep 17 00:00:00 2001
From: David Mitchell <davem@iabyn.com>
Date: Wed, 22 Nov 2017 12:14:42 +0000
Subject: [PATCH] Don't Deparse "${$}abc" as "$$abc"

This fixes ./TEST -deparse op/stat.t

This only fixes multiconcat - in theory concat suffers from the same bug,
although in practice any concat expression involving at least one constant
string will be upgraded to multiconcat.
---
 lib/B/Deparse.pm | 8 ++++++--
 lib/B/Deparse.t  | 5 +++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/B/Deparse.pm b/lib/B/Deparse.pm
index 0cbb890..b19b40f 100644
--- a/lib/B/Deparse.pm
+++ b/lib/B/Deparse.pm
@@ -4405,8 +4405,12 @@ sub do_multiconcat {
         # "foo=$foo bar=$bar "
         my $not_first;
         while (@consts) {
-            $rhs = dq_disambiguate($rhs, $self->dq(shift(@kids), 18))
-                if $not_first;
+            if ($not_first) {
+                my $s = $self->dq(shift(@kids), 18);
+                # don't deparse "a${$}b" as "a$$b"
+                $s = '${$}' if $s eq '$$';
+                $rhs = dq_disambiguate($rhs, $s);
+            }
             $not_first = 1;
             my $c = shift @consts;
             if (defined $c) {
diff --git a/lib/B/Deparse.t b/lib/B/Deparse.t
index ca1bdb4..83e46e8 100644
--- a/lib/B/Deparse.t
+++ b/lib/B/Deparse.t
@@ -2983,3 +2983,8 @@ $res = CORE::keys(%$r2) / 2 - 1;
 my($a, $b);
 $b = $a . $a . $a;
 (($a .= $a) .= $a) .= $a;
+####
+# multiconcat: $$ within string
+my($a, $x);
+$x = "${$}abc";
+$x = "\$$a";
-- 
1.8.3.1