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feat(library/tactic/exact_tactic): generate error if 'exact' tactic produces a term containing metavariables

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Leonardo de Moura 2015-04-06 13:38:53 -07:00
parent 2bc13f6bfd
commit 412f03b08b
3 changed files with 40 additions and 5 deletions
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26
src/library/tactic/exact_tactic.cpp
View file

@ -4,14 +4,16 @@ Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "library/constants.h"
#include "kernel/type_checker.h"
#include "kernel/error_msgs.h"
#include "library/util.h"
#include "library/constants.h"
#include "library/tactic/tactic.h"
#include "library/tactic/elaborate.h"
#include "library/tactic/expr_to_tactic.h"
namespace lean {
tactic exact_tactic(elaborate_fn const & elab, expr const & e, bool enforce_type_during_elaboration) {
tactic exact_tactic(elaborate_fn const & elab, expr const & e, bool enforce_type_during_elaboration, bool allow_metavars) {
return tactic01([=](environment const & env, io_state const & ios, proof_state const & s) {
proof_state new_s = s;
goals const & gs = new_s.get_goals();
@ -19,13 +21,22 @@ tactic exact_tactic(elaborate_fn const & elab, expr const & e, bool enforce_type
throw_no_goal_if_enabled(s);
return none_proof_state();
}
expr t = head(gs).get_type();
expr t = head(gs).get_type();
bool report_unassigned = false;
if (auto new_e = elaborate_with_respect_to(env, ios, elab, new_s, e, some_expr(t),
report_unassigned, enforce_type_during_elaboration)) {
goals const & gs = new_s.get_goals();
if (gs) {
goal const & g = head(gs);
if (!allow_metavars && has_expr_metavar_relaxed(*new_e)) {
throw_tactic_exception_if_enabled(s, [=](formatter const & fmt) {
format r = format("invalid 'exact' tactic, term still contains metavariables "
"after elaboration");
r += pp_indent_expr(fmt, *new_e);
return r;
});
return none_proof_state();
}
substitution subst = new_s.get_subst();
assign(subst, g, *new_e);
return some(proof_state(new_s, tail(gs), subst));
@ -53,12 +64,17 @@ void initialize_exact_tactic() {
register_tac(exact_tac_name,
[](type_checker &, elaborate_fn const & fn, expr const & e, pos_info_provider const *) {
check_tactic_expr(app_arg(e), "invalid 'exact' tactic, invalid argument");
return exact_tactic(fn, get_tactic_expr_expr(app_arg(e)), true);
return exact_tactic(fn, get_tactic_expr_expr(app_arg(e)), true, false);
});
register_tac(rexact_tac_name,
[](type_checker &, elaborate_fn const & fn, expr const & e, pos_info_provider const *) {
check_tactic_expr(app_arg(e), "invalid 'rexact' tactic, invalid argument");
return exact_tactic(fn, get_tactic_expr_expr(app_arg(e)), false);
return exact_tactic(fn, get_tactic_expr_expr(app_arg(e)), false, false);
});
register_tac(refine_tac_name,
[](type_checker &, elaborate_fn const & fn, expr const & e, pos_info_provider const *) {
check_tactic_expr(app_arg(e), "invalid 'refine' tactic, invalid argument");
return exact_tactic(fn, get_tactic_expr_expr(app_arg(e)), true, true);
});
}
void finalize_exact_tactic() {

5
tests/lean/exact_partial.lean Normal file
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@ -0,0 +1,5 @@
example (a b : Prop) : a → b → a ∧ b :=
begin
intros,
exact (and.intro _ _),
end

14
tests/lean/exact_partial.lean.expected.out Normal file
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@ -0,0 +1,14 @@
exact_partial.lean:4:2: error:invalid 'exact' tactic, term still contains metavariables after elaboration
and.intro ?M_1 ?M_2
proof state:
a b : Prop,
a_1 : a,
a_2 : b
⊢ a ∧ b
exact_partial.lean:5:0: error: don't know how to synthesize placeholder
a b : Prop
⊢ a → b → a ∧ b
exact_partial.lean:5:0: error: failed to add declaration '14.0' to environment, value has metavariables
remark: set 'formatter.hide_full_terms' to false to see the complete term
λ (a b : Prop),
?M_1