Polysat: fixes in solver, forbidden intervals for eq_constraint (#5240)

* Rename to neg_cond

* Add some logging utilities

* Implement case of forbidden interval covering the whole domain

* Implement diseq_narrow

* Do not activate constraint if we are in a conflict state

* comments

* Assert that lemma isn't undefined

* Update revert_decision to work in the case where narrowing causes propagation

* Fix case of non-disjunctive lemma from forbidden intervals

* Conflict should not leak outside user scope

* Add guard to decide(), some notes

* Add test case

* Add constraints to watchlist of unassigned variable during propagation

* Move common propagation functionality into base class

* Combine eq/diseq narrow

* Compute forbidden interval for equality constraints by considering them as p <=u 0 (or p >u 0 for disequalities)

src/math/polysat/log_helper.h

@@ -0,0 +1,44 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    Logging support
+
+Abstract:
+
+    Utilities for logging.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+    Jakob Rath 2021-04-6
+
+--*/
+#pragma once
+
+#include <iostream>
+#include "util/util.h"
+
+template <typename T>
+struct show_deref_t {
+  T* ptr;
+};
+
+template <typename T>
+std::ostream& operator<<(std::ostream& os, show_deref_t<T> s) {
+  if (s.ptr)
+    return os << *s.ptr;
+  else
+    return os << "<null>";
+}
+
+template <typename T>
+show_deref_t<T> show_deref(T* ptr) {
+  return show_deref_t<T>{ptr};
+}
+
+template <typename T>
+show_deref_t<T> show_deref(scoped_ptr<T> const& ptr) {
+  return show_deref_t<T>{ptr.get()};
+}