Reduce false positives for @hsh{$s} and @ary[$s] warnings

This resolves tickets #28380 and #114024.

Commit 95a31aad5 did something similar to this for the new %hash{...}
syntax.  This commit extends it to @ slices and combines the two
code paths.

The heuristics in toke.c can easily produce false positives.  So the
op is flagged as being a candidate for the warning.  Then when op.c
has the op tree available, it examines it to see whether the heuristic
may have been a false positive.

This avoids bugs with qw "foo bar baz" and sub calls triggering
the warning.

The source code is no longer available for the warning, so we recon-
struct it from the op tree, skipping the subscript if it is anything
other than a const op.

This means that @hash{$foo} comes out as @hash{...} and @hash{foo} as
@hash{"foo"}.  It also meeans that @hash{"]"} is displayed correctly
instead of as @hash{"].

Commit 95a31aad5 also modified the heuristic for %hash{...} to exempt
qw altogether.  But it did not exempt it if it was preceded by a tab.
So this commit rectifies that.

This commit also improves the false positive detection by exempting
any ops returning lists that can get past toke.c’s heuristic.  I went
through the entire list of ops, but I may have missed some.

Also, @ slices on the lhs of = are exempt, as they change the context
and are hence actually useful.

1 files changed, 1 insertions, 1 deletions

diff --git a/perly.h b/perly.h
index 155dea02d5..3b708a8c1b 100644
--- a/perly.h
+++ b/perly.h
@@ -266,6 +266,6 @@ typedef union YYSTYPE
 
 
 /* Generated from:
- * 80609b739b642fa427503886445869dfd47021624a1977b902211b38043ed9f1 perly.y
+ * 5b290f371f373fb17e073f602c676e436e9d457a1d4db67d192e3cfa0eeb36d7 perly.y
  * 5c9d2a0262457fe9b70073fc8ad6c188f812f38ad57712b7e2f53daa01b297cc regen_perly.pl
  * ex: set ro: */