fix #2720, unsound preprocessing in elim_uncnstr_tactic where datatype properties of eliminated subterms is forgotten

Signed-off-by: Nikolaj Bjorner <[email protected]>

Author: NikolajBjorner

src/tactic/core/elim_uncnstr_tactic.cpp

@@ -675,18 +675,7 @@ class elim_uncnstr_tactic : public tactic {
         }
 
         app * process_datatype_app(func_decl * f, unsigned num, expr * const * args) {
-            if (m_dt_util.is_recognizer(f)) {
-                SASSERT(num == 1);
-                if (uncnstr(args[0])) {
-                    if (!m_mc) {
-                        app * r;
-                        mk_fresh_uncnstr_var_for(f, num, args, r);
-                        return r;
-                    }
-                    // TODO: handle model generation
-                }
-            }
-            else if (m_dt_util.is_accessor(f)) {
+            if (m_dt_util.is_accessor(f)) {
                 SASSERT(num == 1);
                 if (uncnstr(args[0])) {
                     if (!m_mc) {
@@ -713,20 +702,6 @@ class elim_uncnstr_tactic : public tactic {
                     return u;
                 }
             }
-            else if (m_dt_util.is_constructor(f)) {
-                if (uncnstr(num, args)) {
-                    app * u;
-                    if (!mk_fresh_uncnstr_var_for(f, num, args, u))
-                        return u;
-                    if (!m_mc)
-                        return u;
-                    ptr_vector<func_decl> const & accs = *m_dt_util.get_constructor_accessors(f);
-                    for (unsigned i = 0; i < num; i++) {
-                        add_def(args[i], m().mk_app(accs[i], u));
-                    }
-                    return u;
-                }
-            }
             return nullptr;
         }