Fewer false positives for %hash{$scalar} warning

Instead of warning in the lexer, flag the op and then warn in op.c,
when the op tree is available, so we don’t end up warning for actual
lists or for sub calls.

Also, only warn in scalar context, as in list context $hash{$scalar}
and %hash{$scalar} do different things.

In op.c we no longer have easy access to the source code, so recon-
struct the hash/array access based on the op tree.  This means
%hash{foo} becomes %hash{"foo"}.  We only reconstruct constant keys,
so %hash{++$x} becomes %hash{...}.  This also corrects erroneous
dumps, like %hash{"} for %hash{"}"}.

Instead of triggering the warning solely based on the op tree, we
still keep the heuristic in toke.c, so that common workarounds for
that warning (e.g., {q<key>} and {("key")}) continue to work.

The heuristic in toke.c is tweaked to avoid warning for qw().

In a future commit I plan to extend this to the existing @array[0] and
@hash{key} warnings, to avoid false positives.

1 files changed, 22 insertions, 42 deletions

diff --git a/perly.h b/perly.h
index dcf67d97c5..155dea02d5 100644
--- a/perly.h
+++ b/perly.h
@@ -5,24 +5,27 @@
  */
 
 #ifdef PERL_CORE
-/* A Bison parser, made by GNU Bison 2.6.5.  */
+/* A Bison parser, made by GNU Bison 2.3.  */
 
-/* Bison interface for Yacc-like parsers in C
-   
-      Copyright (C) 1984, 1989-1990, 2000-2012 Free Software Foundation, Inc.
-   
-   This program is free software: you can redistribute it and/or modify
+/* Skeleton interface for Bison's Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006
+   Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation, either version 3 of the License, or
-   (at your option) any later version.
-   
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-   
+
    You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
 
 /* As a special exception, you may create a larger work that contains
    part or all of the Bison parser skeleton and distribute that work
@@ -33,18 +36,10 @@
    special exception, which will cause the skeleton and the resulting
    Bison output files to be licensed under the GNU General Public
    License without this special exception.
-   
+
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
-/* Enabling traces.  */
-#ifndef YYDEBUG
-# define YYDEBUG 0
-#endif
-#if YYDEBUG
-extern int yydebug;
-#endif
-
 /* Tokens.  */
 #ifndef YYTOKENTYPE
 # define YYTOKENTYPE
@@ -133,7 +128,6 @@ extern int yydebug;
      PEG = 337
    };
 #endif
-
 /* Tokens.  */
 #define GRAMPROG 258
 #define GRAMEXPR 259
@@ -217,6 +211,8 @@ extern int yydebug;
 #define PEG 337
 
 
+
+
 #ifdef PERL_IN_TOKE_C
 static bool
 S_is_opval_token(int type) {
@@ -243,8 +239,6 @@ S_is_opval_token(int type) {
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef union YYSTYPE
 {
-/* Line 2042 of yacc.c  */
-
     I32	ival; /* __DEFAULT__ (marker for regen_perly.pl;
 				must always be 1st union member) */
     char *pval;
@@ -260,32 +254,18 @@ typedef union YYSTYPE
 #ifdef PERL_MAD
     TOKEN* tkval;
 #endif
-
-
-/* Line 2042 of yacc.c  */
-} YYSTYPE;
-# define YYSTYPE_IS_TRIVIAL 1
+}
+/* Line 1529 of yacc.c.  */
+	YYSTYPE;
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
+# define YYSTYPE_IS_TRIVIAL 1
 #endif
 
 
-#ifdef YYPARSE_PARAM
-#if defined __STDC__ || defined __cplusplus
-int yyparse (void *YYPARSE_PARAM);
-#else
-int yyparse ();
-#endif
-#else /* ! YYPARSE_PARAM */
-#if defined __STDC__ || defined __cplusplus
-int yyparse (void);
-#else
-int yyparse ();
-#endif
-#endif /* ! YYPARSE_PARAM */
 
 
 /* Generated from:
- * 1c6010b3d1651d4fc7cbfc329723c507767b4230ac920ae0ffde8f344f4a0ab4 perly.y
+ * 80609b739b642fa427503886445869dfd47021624a1977b902211b38043ed9f1 perly.y
  * 5c9d2a0262457fe9b70073fc8ad6c188f812f38ad57712b7e2f53daa01b297cc regen_perly.pl
  * ex: set ro: */