Fix thinko in tok_is_keyword(): it was looking at the wrong union variant

of YYSTYPE, and hence returning the wrong answer for cases where a plpgsql
"unreserved keyword" really does conflict with a variable name.  Obviously
I didn't test this enough :-(.  Per bug #5524 from Peter Gagarinov.

src/pl/plpgsql/src/gram.y

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.142 2010/03/03 01:53:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.143 2010/06/25 16:40:13 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2080,8 +2080,8 @@ tok_is_keyword(int token, union YYSTYPE *lval,
 		 * match composite names (hence an unreserved word followed by "."
 		 * will not be recognized).
 		 */
-		if (!lval->word.quoted && lval->word.ident != NULL &&
+		if (!lval->wdatum.quoted && lval->wdatum.ident != NULL &&
-			strcmp(lval->word.ident, kw_str) == 0)
+			strcmp(lval->wdatum.ident, kw_str) == 0)
 			return true;
 	}
 	return false;				/* not the keyword */

src/test/regress/expected/plpgsql.out

@@ -3578,6 +3578,20 @@ $$ language plpgsql;
 select raise_test();
 ERROR:  RAISE without parameters cannot be used outside an exception handler
 CONTEXT:  PL/pgSQL function "raise_test"
+-- check cases where implicit SQLSTATE variable could be confused with
+-- SQLSTATE as a keyword, cf bug #5524
+create or replace function raise_test() returns void as $$
+begin
+  perform 1/0;
+exception
+  when sqlstate '22012' then
+    raise notice using message = sqlstate;
+    raise sqlstate '22012' using message = 'substitute message';
+end;
+$$ language plpgsql;
+select raise_test();
+NOTICE:  22012
+ERROR:  substitute message
 drop function raise_test();
 -- test CASE statement
 create or replace function case_test(bigint) returns text as $$

src/test/regress/sql/plpgsql.sql

@@ -2916,6 +2916,20 @@ $$ language plpgsql;
 
 select raise_test();
 
+-- check cases where implicit SQLSTATE variable could be confused with
+-- SQLSTATE as a keyword, cf bug #5524
+create or replace function raise_test() returns void as $$
+begin
+  perform 1/0;
+exception
+  when sqlstate '22012' then
+    raise notice using message = sqlstate;
+    raise sqlstate '22012' using message = 'substitute message';
+end;
+$$ language plpgsql;
+
+select raise_test();
+
 drop function raise_test();
 
 -- test CASE statement