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fix(frontends/lean/elaborator): fixes #687

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This commit is contained in:
Leonardo de Moura 2015-06-28 19:58:57 -07:00
parent ecfc01b2d0
commit 95720b1670
3 changed files with 54 additions and 12 deletions
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28
src/frontends/lean/elaborator.cpp
View file

@ -81,13 +81,15 @@ struct elaborator::choice_expr_elaborator : public choice_iterator {
elaborator & m_elab;
local_context m_context;
local_context m_full_context;
bool m_in_equation_lhs;
expr m_meta;
expr m_type;
expr m_choice;
unsigned m_idx;
choice_expr_elaborator(elaborator & elab, local_context const & ctx, local_context const & full_ctx,
choice_expr_elaborator(elaborator & elab, local_context const & ctx, local_context const & full_ctx, bool in_equation_lhs,
expr const & meta, expr const & type, expr const & c):
m_elab(elab), m_context(ctx), m_full_context(full_ctx), m_meta(meta),
m_elab(elab), m_context(ctx), m_full_context(full_ctx), m_in_equation_lhs(in_equation_lhs), m_meta(meta),
m_type(type), m_choice(c), m_idx(get_num_choices(m_choice)) {
}
@ -98,8 +100,9 @@ struct elaborator::choice_expr_elaborator : public choice_iterator {
expr const & f = get_app_fn(c);
m_elab.save_identifier_info(f);
try {
flet<local_context> set1(m_elab.m_context, m_context);
flet<local_context> set2(m_elab.m_full_context, m_full_context);
flet<local_context> set1(m_elab.m_context, m_context);
flet<local_context> set2(m_elab.m_full_context, m_full_context);
flet<bool> set3(m_elab.m_in_equation_lhs, m_in_equation_lhs);
pair<expr, constraint_seq> rcs = m_elab.visit(c);
expr r = rcs.first;
constraint_seq cs = rcs.second;
@ -314,9 +317,10 @@ expr elaborator::visit_choice(expr const & e, optional<expr> const & t, constrai
register_meta(m);
local_context ctx = m_context;
local_context full_ctx = m_full_context;
bool in_equation_lhs = m_in_equation_lhs;
auto fn = [=](expr const & meta, expr const & type, substitution const & /* s */,
name_generator && /* ngen */) {
return choose(std::make_shared<choice_expr_elaborator>(*this, ctx, full_ctx, meta, type, e));
return choose(std::make_shared<choice_expr_elaborator>(*this, ctx, full_ctx, in_equation_lhs, meta, type, e));
};
auto pp_fn = [=](formatter const & fmt, pos_info_provider const * pos_prov, substitution const &, bool is_main, bool) {
format r = pp_previous_error_header(fmt, pos_prov, some_expr(e), is_main);
@ -553,12 +557,13 @@ pair<expr, constraint_seq> elaborator::mk_delayed_coercion(
}
/** \brief Given a term <tt>a : a_type</tt>, ensure it has type \c expected_type. Apply coercions if needed */
pair<expr, constraint_seq> elaborator::ensure_has_type(
expr const & a, expr const & a_type, expr const & expected_type, justification const & j) {
pair<expr, constraint_seq> elaborator::ensure_has_type_core(
expr const & a, expr const & a_type, expr const & expected_type, bool use_expensive_coercions, justification const & j) {
bool lifted_coe = false;
if (has_coercions_from(a_type, lifted_coe) && ((!lifted_coe && is_meta(expected_type)) || (lifted_coe && is_pi_meta(expected_type)))) {
if (use_expensive_coercions &&
has_coercions_from(a_type, lifted_coe) && ((!lifted_coe && is_meta(expected_type)) || (lifted_coe && is_pi_meta(expected_type)))) {
return mk_delayed_coercion(a, a_type, expected_type, j);
} else if (!m_in_equation_lhs && is_meta(a_type) && has_coercions_to(expected_type)) {
} else if (use_expensive_coercions && !m_in_equation_lhs && is_meta(a_type) && has_coercions_to(expected_type)) {
return mk_delayed_coercion(a, a_type, expected_type, j);
} else {
pair<bool, constraint_seq> dcs;
@ -668,7 +673,10 @@ expr elaborator::visit_app(expr const & e, constraint_seq & cs) {
expr a_type = infer_type(a, a_cs);
expr r = mk_app(f, a, e.get_tag());
justification j = mk_app_justification(r, f_type, a, a_type);
auto new_a_cs = ensure_has_type(a, a_type, d_type, j);
// If the application is an equations expression, then we are compiling a match-with, and expensive
// coercions should not be considered.
bool use_expensive_coercions = !is_equations(app_fn(e));
auto new_a_cs = ensure_has_type_core(a, a_type, d_type, use_expensive_coercions, j);
expr new_a = new_a_cs.first;
cs += f_cs + new_a_cs.second + a_cs;
return update_app(r, app_fn(r), new_a);

7
src/frontends/lean/elaborator.h
View file

@ -124,9 +124,12 @@ class elaborator : public coercion_info_manager {
expr apply_coercion(expr const & a, expr a_type, expr d_type);
pair<expr, constraint_seq> mk_delayed_coercion(expr const & a, expr const & a_type, expr const & expected_type,
justification const & j);
pair<expr, constraint_seq> ensure_has_type_core(expr const & a, expr const & a_type, expr const & expected_type,
bool use_expensive_coercions, justification const & j);
pair<expr, constraint_seq> ensure_has_type(expr const & a, expr const & a_type, expr const & expected_type,
justification const & j);
justification const & j) {
return ensure_has_type_core(a, a_type, expected_type, true, j);
}
bool is_choice_app(expr const & e);
expr visit_choice_app(expr const & e, constraint_seq & cs);
expr visit_app(expr const & e, constraint_seq & cs);

31
tests/lean/run/687.lean Normal file
View file

@ -0,0 +1,31 @@
import data.fin
section rot
open nat fin eq.ops algebra
open eq.ops
definition rotr₀ {n : nat} : fin n → fin n :=
match n with
| 0 := take i, elim0 i
| (succ k) := madd (-maxi)
end
definition rotr₁ {n : nat} : fin n → fin n :=
match n with
| zero := take i, elim0 i
| (succ k) := madd (-maxi)
end
definition rotr₂ : ∀ {n : nat}, fin n → fin n
| 0 i := elim0 i
| (succ n) i := madd (has_neg.neg maxi) i
definition rotr₃ : ∀ {n : nat}, fin n → fin n
| 0 := take i, elim0 i
| (succ n) := madd (-maxi)
definition rotr₄ : ∀ {n : nat}, fin n → fin n
| 0 i := elim0 i
| (succ n) i := madd (-maxi) i
end rot