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feat(library/tactic/inversion_tactic): remove hypothesis being destructed

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addresses second issue in #468
This commit is contained in:
Leonardo de Moura 2015-03-11 20:41:09 -07:00
parent 0a5340aa22
commit b5fb7c734e
2 changed files with 40 additions and 1 deletions
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40
src/library/tactic/inversion_tactic.cpp
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@ -19,6 +19,7 @@ Author: Leonardo de Moura
#include "library/tactic/expr_to_tactic.h"
#include "library/tactic/class_instance_synth.h"
#include "library/tactic/inversion_tactic.h"
#include "library/tactic/clear_tactic.h"
namespace lean {
namespace inversion {
@ -920,6 +921,44 @@ class inversion_tac {
return mk_pair(to_list(new_goals), to_list(new_rs));
}
goal clear_hypothesis(goal const & g, name const & h) {
if (auto p = g.find_hyp_from_internal_name(h)) {
expr const & h = p->first;
unsigned i = p->second;
buffer<expr> hyps;
g.get_hyps(hyps);
hyps.erase(hyps.size() - i - 1);
if (depends_on(g.get_type(), h) || depends_on(i, hyps.end() - i, h)) {
return g; // other hypotheses or result type depend on h
}
expr new_type = g.get_type();
expr new_meta = mk_app(mk_metavar(m_ngen.next(), Pi(hyps, new_type)), hyps);
goal new_g(new_meta, new_type);
expr val = g.abstract(new_meta);
assign(g.get_name(), val);
return new_g;
} else {
return g;
}
}
list<goal> clear_hypothesis(list<goal> const & gs, list<rename_map> rs, name const & h_name, expr const & h_type) {
buffer<goal> new_gs;
optional<name> lhs_name; // If h_type is of the form lhs = rhs, and lhs is also a hypothesis, then we also remove it.
if (is_eq(h_type) && is_local(app_arg(app_fn(h_type)))) {
lhs_name = mlocal_name(app_arg(app_fn(h_type)));
}
for (goal const & g : gs) {
rename_map const & m = head(rs);
goal new_g = clear_hypothesis(g, m.find(h_name));
if (lhs_name)
new_g = clear_hypothesis(new_g, *lhs_name);
new_gs.push_back(new_g);
rs = tail(rs);
}
return to_list(new_gs);
}
public:
inversion_tac(environment const & env, io_state const & ios, name_generator const & ngen,
type_checker & tc, substitution const & subst, list<name> const & ids,
@ -963,6 +1002,7 @@ public:
list<goal> gs4;
list<rename_map> rs;
std::tie(gs4, args, new_imps, rs) = unify_eqs(gs3, args, new_imps);
gs4 = clear_hypothesis(gs4, rs, mlocal_name(h), h_type);
return optional<result>(result(gs4, args, new_imps, rs, m_ngen, m_subst));
}
} catch (inversion_exception & ex) {

1
tests/lean/inv_del.lean.expected.out
View file

@ -2,7 +2,6 @@ inv_del.lean:15:2: error: unsolved subgoals
A : Type,
P : vec A 1 → Type,
H : Π (a : A), P (vone a),
v : vec A 1,
a : A
⊢ P (vone a)
inv_del.lean:15:2: error: failed to add declaration 'vec.eone' to environment, value has metavariables