Drop hash fallback via string (closes gh-89)

Author: inducer

islpy/__init__.py

@@ -307,23 +307,14 @@ def generic_repr(self):
         getattr(prn, f"print_{self._base_name}")(self)
         return f'{type(self).__name__}("{prn.get_str()}")'
 
-    def generic_hash(self):
-        return hash((type(self), str(self)))
-
-    def generic_isl_hash(self):
-        return self.get_hash()
-
     for cls in ALL_CLASSES:
         if (hasattr(cls, "_base_name")
                 and hasattr(Printer, f"print_{cls._base_name}")):
             cls.__str__ = generic_str
             cls.__repr__ = generic_repr
 
-            if not hasattr(cls, "get_hash"):
-                cls.__hash__ = generic_hash
-
-        if hasattr(cls, "get_hash"):
-            cls.__hash__ = generic_isl_hash
+        if not hasattr(cls, "__hash__"):
+            raise AssertionError(f"not hashable: {cls}")
 
     # }}}