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fix(frontends/lean/calc): add expected type for single-step calc expressions, fixes #357

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This is not an issue for calc expressions containing multiple steps,
since the transitivity step will "force" the expected type for the proofs.
This commit is contained in:
Leonardo de Moura 2014-11-29 15:35:09 -08:00
parent a97d7ffed7
commit bc65aeb5e1
2 changed files with 20 additions and 6 deletions
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22
src/frontends/lean/calc.cpp
View file

@ -20,6 +20,7 @@ Author: Leonardo de Moura
#include "library/explicit.h"
#include "library/scoped_ext.h"
#include "library/annotation.h"
#include "library/typed_expr.h"
#include "library/sorry.h"
#include "library/tactic/expr_to_tactic.h"
#include "frontends/lean/parser.h"
@ -296,8 +297,8 @@ static void collect_rhss(std::vector<calc_step> const & steps, buffer<expr> & rh
lean_assert(!rhss.empty());
}
static void join(parser & p, std::vector<calc_step> const & steps1, std::vector<calc_step> const & steps2, std::vector<calc_step> & res_steps,
pos_info const & pos) {
static void join(parser & p, std::vector<calc_step> const & steps1, std::vector<calc_step> const & steps2,
std::vector<calc_step> & res_steps, pos_info const & pos) {
res_steps.clear();
calc_state const & state = calc_ext::get_state(p.env());
for (calc_step const & s1 : steps1) {
@ -324,11 +325,14 @@ expr parse_calc(parser & p) {
buffer<expr> rhss;
std::vector<calc_step> steps, new_steps, next_steps;
auto pos = p.pos();
decode_expr(p.parse_expr(), preds, pos);
expr first_pred = p.parse_expr();
decode_expr(first_pred, preds, pos);
parse_calc_proof(p, preds, steps);
bool single = true; // true if calc has only one step
expr dummy = mk_expr_placeholder();
while (p.curr_is_token(get_ellipsis_tk())) {
pos = p.pos();
single = false;
pos = p.pos();
p.next();
decode_expr(p.parse_led(dummy), preds, pos);
collect_rhss(steps, rhss);
@ -348,8 +352,14 @@ expr parse_calc(parser & p) {
steps.swap(next_steps);
}
buffer<expr> choices;
for (auto const & s : steps)
choices.push_back(step_proof(s));
for (auto const & s : steps) {
if (single) {
expr new_s = p.save_pos(mk_typed_expr(first_pred, step_proof(s)), pos);
choices.push_back(new_s);
} else {
choices.push_back(step_proof(s));
}
}
return p.save_pos(mk_choice(choices.size(), choices.data()), pos);
}

4
tests/lean/run/calc_bug.lean Normal file
View file

@ -0,0 +1,4 @@
import logic
definition foo (a : Type) :=
calc a = a : rfl