Modify the handling of RAISE without parameters so that the error it throws

can be caught in the same places that could catch an ordinary RAISE ERROR
in the same location.  The previous coding insisted on throwing the error
from the block containing the active exception handler; which is arguably
more surprising, and definitely unlike Oracle's behavior.

Not back-patching, since this is a pretty obscure corner case.  The risk
of breaking somebody's code in a minor version update seems to outweigh
any possible benefit.

Piyush Newe, reviewed by David Fetter

src/test/regress/sql/plpgsql.sql

@@ -1966,6 +1966,31 @@ $$ language plpgsql;
 
 select raise_test2(10);
 
+-- Test re-RAISE inside a nested exception block.  This case is allowed
+-- by Oracle's PL/SQL but was handled differently by PG before 9.1.
+
+CREATE FUNCTION reraise_test() RETURNS void AS $$
+BEGIN
+   BEGIN
+       RAISE syntax_error;
+   EXCEPTION
+       WHEN syntax_error THEN
+           BEGIN
+               raise notice 'exception % thrown in inner block, reraising', sqlerrm;
+               RAISE;
+           EXCEPTION
+               WHEN OTHERS THEN
+                   raise notice 'RIGHT - exception % caught in inner block', sqlerrm;
+           END;
+   END;
+EXCEPTION
+   WHEN OTHERS THEN
+       raise notice 'WRONG - exception % caught in outer block', sqlerrm;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT reraise_test();
+
 --
 -- reject function definitions that contain malformed SQL queries at
 -- compile-time, where possible