void tmp_type_context::update_assignment(level const & u, level const & v) {
unsigned idx = to_meta_idx(u);
lean_assert(idx < m_uassignment.size()); // see comments above
m_uassignment[idx] = v;
if (!m_scopes.empty())
m_trail.emplace_back(trail_kind::Level, idx);
}
optional<expr> tmp_type_context::get_assignment(expr const & m) const {
unsigned idx = to_meta_idx(m);
// if the following assetion is violated, we have two options:
// 1- We should create the meta-variable using mk_mvar
// 2- We create using mk_idx_metavar, and notify this object using
// set_next_mvar_idx
lean_assert(idx < m_eassignment.size());
return m_eassignment[idx];
}
optional<level> tmp_type_context::get_assignment(level const & u) const {
unsigned idx = to_meta_idx(u);
// if the following assetion is violated, we have two options:
// 1- We should create the meta-variable using mk_uvar
// 2- We create using mk_idx_metauniv, and notify this object using
// set_next_uvar_idx
lean_assert(idx < m_uassignment.size());
return m_uassignment[idx];
}
void tmp_type_context::update_assignment(expr const & m, expr const & v) {
unsigned idx = to_meta_idx(m);
lean_assert(idx < m_eassignment.size()); // see comments above
// Remark: type class resolution may update an already assigned meta-variable with a
// definitionally equal, but the new assignment is "nicer", i.e., it has not been
// accidentally unfolded by the unifier.
// We only add the entry to the trail if it was not assigned before.
bool was_assigned = static_cast<bool>(m_eassignment[idx]);
m_eassignment[idx] = v;
if (!m_scopes.empty() && !was_assigned)
m_trail.emplace_back(trail_kind::Expr, idx);
}