fix false alarm - unreachable code

Author: okbob

expected/plpgsql_check_active.out

@@ -3554,3 +3554,57 @@ select * from plpgsql_check_function('test_crash', fatal_errors := true);
 (5 rows)
 
 drop function test_crash();
+-- fix false alarm reported by Piotr Stepniewski
+create or replace function public.fx()
+returns void
+language plpgsql
+as $function$
+begin
+  raise exception 'xxx';
+end;
+$function$;
+-- show raise nothing
+select * from plpgsql_check_function('fx()');
+ plpgsql_check_function 
+------------------------
+(0 rows)
+
+create table errtab(
+  message text,
+  code character(5)
+);
+create or replace function public.fx()
+returns void
+language plpgsql
+as $function$
+declare
+  var errtab%rowtype;
+begin
+  raise exception using message = var.message, errcode = var.code;
+end;
+$function$;
+-- should not to crash
+select * from plpgsql_check_function('fx()');
+ plpgsql_check_function 
+------------------------
+(0 rows)
+
+create or replace function public.fx()
+returns void
+language plpgsql
+as $function$
+declare
+  var errtab%rowtype;
+begin
+  raise exception using message = var.message, errcode = var.code, hint = var.hint;
+end;
+$function$;
+-- should not to crash
+select * from plpgsql_check_function('fx()');
+                plpgsql_check_function                
+------------------------------------------------------
+ error:42703:5:RAISE:record "var" has no field "hint"
+ Context: SQL statement "SELECT var.hint"
+(2 rows)
+
+drop function fx();

sql/plpgsql_check_active.sql

@@ -2580,3 +2580,53 @@ select * from plpgsql_check_function('test_crash', fatal_errors := false);
 select * from plpgsql_check_function('test_crash', fatal_errors := true);
 
 drop function test_crash();
+
+-- fix false alarm reported by Piotr Stepniewski
+create or replace function public.fx()
+returns void
+language plpgsql
+as $function$
+begin
+  raise exception 'xxx';
+end;
+$function$;
+
+-- show raise nothing
+select * from plpgsql_check_function('fx()');
+
+create table errtab(
+  message text,
+  code character(5)
+);
+
+create or replace function public.fx()
+returns void
+language plpgsql
+as $function$
+declare
+  var errtab%rowtype;
+begin
+  raise exception using message = var.message, errcode = var.code;
+end;
+$function$;
+
+-- should not to crash
+select * from plpgsql_check_function('fx()');
+
+create or replace function public.fx()
+returns void
+language plpgsql
+as $function$
+declare
+  var errtab%rowtype;
+begin
+  raise exception using message = var.message, errcode = var.code, hint = var.hint;
+end;
+$function$;
+
+-- should not to crash
+select * from plpgsql_check_function('fx()');
+
+drop function fx();
+
+

src/stmtwalk.c

@@ -1347,7 +1347,8 @@ check_stmts(PLpgSQL_checkstate *cstate, List *stmts, int *closing, List **except
 		exceptions_local = NIL;
 		plpgsql_check_stmt(cstate, stmt, &closing_local, &exceptions_local);
 
-		if (dead_code_alert)
+		/* raise dead_code_alert only for visible statements */
+		if (dead_code_alert && stmt->lineno > 0)
 		{
 			plpgsql_check_put_error(cstate,
 						  0, stmt->lineno,