%---------------------------------------------------------------------------%
% vim: ts=4 sw=4 et ft=mercury
%---------------------------------------------------------------------------%
%
% Test for Bug #309, existentially quantifying a dummy variable such as
% store(S) can cause the compiler to crash if the variable's register is
% clubbered and the value needs to be retrived from the stack.

% $ mmc -C environment.m
% Making Mercury/int3s/environment.int3
% Making Mercury/ints/environment.int
% Making Mercury/cs/environment.c
% Uncaught Mercury exception:
% Software Error: ll_backend.llds_out.llds_out_data:
%   predicate `ll_backend.llds_out.llds_out_data.output_lval'/4:
%   Unexpected: stack var out of range

:- module exists_dummy.

:- interface.

:- import_module map.
:- import_module store.
:- import_module string.

:- type lisp_val
    --->    lisp_val.

:- type mappings(S) == generic_mutvar(map(string, lisp_val), S).

:- type environment(S)
    --->    root_environment(mappings(S))
    ;       child_environment(environment(S), mappings(S)).

:- some[S] pred root_env(environment(S)::out, S::uo) is det => store(S).

:- implementation.

root_env(Environment, Store) :-
    store.init(Store0),
    store.new_mutvar(map.init, Mappings, Store0, Store),
    Environment = root_environment(Mappings).