Don’t inline sub(){0; $x} if $x changes elsewhere

Some op trees will turn a sub into a constant even if they
are more than just a simple constant or lexical variable.  In
particular, a statement optimised away followed by a lexi-
cal variable is eligible for inlining.  As discussed in
<20141101170924.17763.qmail@lists-nntp.develooper.com>, make these
more complex op trees follow closure rules properly.  If the outer
lexical is used in lvalue context in places other than its declara-
tion, then we should forego inlining.

1 files changed, 21 insertions, 1 deletions

diff --git a/t/op/const-optree.t b/t/op/const-optree.t
index 9ef183efc7..0d5d747cf6 100644
--- a/t/op/const-optree.t
+++ b/t/op/const-optree.t
@@ -8,7 +8,7 @@ BEGIN {
     require './test.pl';
     @INC = '../lib';
 }
-plan 16;
+plan 26;
 
 # @tests is an array of hash refs, each of which can have various keys:
 #
@@ -55,6 +55,26 @@ push @tests, {
 };
 
 push @tests, {
+  nickname    => 'sub () { 0; $x } with $x modified elsewhere',
+  generator   => sub { my $x = 5; my $ret = sub(){0;$x}; $x = 8; $ret },
+  retval      => 8,
+  same_retval => 0,
+  inlinable   => 0,
+  deprecated  => 0,
+  method      => 0,
+};
+
+push @tests, {
+  nickname    => 'sub () { 0; $x } with $x unmodified elsewhere',
+  generator   => sub { my $x = 5; my $y = $x; sub(){0;$x} },
+  retval      => 5,
+  same_retval => 0,
+  inlinable   => 1,
+  deprecated  => 0,
+  method      => 0,
+};
+
+push @tests, {
   nickname    => 'sub:method with simple lexical',
   generator   => sub { my $y; sub():method{$y} },
   retval      => undef,