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fix(library/tactic/subst_tactic): use intermediate state for errors

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This commit is contained in:
Leonardo de Moura 2016-06-20 10:22:36 -07:00
parent a85d027c90
commit 397ea25e24
1 changed files with 39 additions and 35 deletions
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74
src/library/tactic/subst_tactic.cpp
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@ -37,44 +37,48 @@ vm_obj tactic_subst_core(name const & n, bool symm, tactic_state const & s) {
optional<tactic_state> s2 = intron(2, s1, lhsH);
if (!s2) return mk_tactic_exception("subst tactic failed, unexpected failure during intro", s);
lean_assert(!s2->mctx().is_assigned(head(s2->goals())));
lctx = s2->get_main_goal_decl()->get_context();
expr type = s2->get_main_goal_decl()->get_type();
lhs = lctx.get_local_decl(lhsH[0])->mk_ref();
expr H = lctx.get_local_decl(lhsH[1])->mk_ref();
bool depH = depends_on(type, H);
expr new_type = instantiate(abstract_local(type, lhs), rhs);
metavar_context mctx = s2->mctx();
lean_assert(!mctx.is_assigned(head(s2->goals())));
type_context ctx = mk_type_context_for(*s2, mctx);
app_builder builder = mk_app_builder_for(ctx);
expr motive;
if (depH) {
new_type = instantiate(abstract_local(new_type, H), builder.mk_eq_refl(rhs));
if (symm) {
motive = ctx.mk_lambda({lhs, H}, type);
try {
lctx = s2->get_main_goal_decl()->get_context();
expr type = s2->get_main_goal_decl()->get_type();
lhs = lctx.get_local_decl(lhsH[0])->mk_ref();
expr H = lctx.get_local_decl(lhsH[1])->mk_ref();
bool depH = depends_on(type, H);
expr new_type = instantiate(abstract_local(type, lhs), rhs);
metavar_context mctx = s2->mctx();
lean_assert(!mctx.is_assigned(head(s2->goals())));
type_context ctx = mk_type_context_for(*s2, mctx);
app_builder builder = mk_app_builder_for(ctx);
expr motive;
if (depH) {
new_type = instantiate(abstract_local(new_type, H), builder.mk_eq_refl(rhs));
if (symm) {
motive = ctx.mk_lambda({lhs, H}, type);
} else {
motive = mk_lambda("H", builder.mk_eq(rhs, lhs), type);
motive = ctx.mk_lambda(lhs, motive);
}
} else {
motive = mk_lambda("H", builder.mk_eq(rhs, lhs), type);
motive = ctx.mk_lambda(lhs, motive);
motive = ctx.mk_lambda(lhs, type);
}
} else {
motive = ctx.mk_lambda(lhs, type);
expr major = symm ? H : builder.mk_eq_symm(H);
expr new_M = mctx.mk_metavar_decl(lctx, new_type);
expr minor = new_M;
expr new_val = depH ? builder.mk_eq_drec(motive, minor, major) : builder.mk_eq_rec(motive, minor, major);
mctx.assign(head(s2->goals()), new_val);
list<expr> new_gs(new_M, tail(s.goals()));
tactic_state s3 = set_mctx_goals(*s2, mctx, new_gs);
vm_obj o4 = clear_internal(lhsH[1], s3);
optional<tactic_state> s4 = is_tactic_success(o4);
if (!s4) return o4;
vm_obj o5 = clear_internal(lhsH[0], *s4);
optional<tactic_state> s5 = is_tactic_success(o5);
if (!s5) return o5;
optional<tactic_state> s6 = intron(to_revert.size() - 2, *s5);
if (!s6) return mk_tactic_exception("subst tactic failed, unexpected failure during intro", s);
return mk_tactic_success(*s6);
} catch (exception & ex) {
return mk_tactic_exception(ex, *s2);
}
expr major = symm ? H : builder.mk_eq_symm(H);
expr new_M = mctx.mk_metavar_decl(lctx, new_type);
expr minor = new_M;
expr new_val = depH ? builder.mk_eq_drec(motive, minor, major) : builder.mk_eq_rec(motive, minor, major);
mctx.assign(head(s2->goals()), new_val);
list<expr> new_gs(new_M, tail(s.goals()));
tactic_state s3 = set_mctx_goals(*s2, mctx, new_gs);
vm_obj o4 = clear_internal(lhsH[1], s3);
optional<tactic_state> s4 = is_tactic_success(o4);
if (!s4) return o4;
vm_obj o5 = clear_internal(lhsH[0], *s4);
optional<tactic_state> s5 = is_tactic_success(o5);
if (!s5) return o5;
optional<tactic_state> s6 = intron(to_revert.size() - 2, *s5);
if (!s6) return mk_tactic_exception("subst tactic failed, unexpected failure during intro", s);
return mk_tactic_success(*s6);
} catch (exception & ex) {
return mk_tactic_exception(ex, s);
}