Add support for NewType

crosshair/core.py

@@ -29,11 +29,11 @@
     Collection,
     Dict,
     FrozenSet,
-    Generator,
     Iterable,
     List,
     Mapping,
     MutableMapping,
+    NewType,
     Optional,
     Sequence,
     Set,
@@ -604,6 +604,8 @@ def proxy_for_type(
         if proxy_factory:
             recursive_proxy_factory = SymbolicFactory(space, typ, varname)
             return proxy_factory(recursive_proxy_factory, *type_args)
+        if hasattr(typ, "__supertype__") and typing_inspect.is_new_type(typ):
+            return proxy_for_type(typ.__supertype__, varname, allow_subtypes)  # type: ignore
         if allow_subtypes and typ is not object:
             typ = choose_type(space, typ, varname)
             if typ is None:  # (happens if typ and all subtypes are abstract)

crosshair/core_test.py

@@ -28,6 +28,7 @@
     standalone_statespace,
 )
 from crosshair.fnutil import FunctionInfo, walk_qualname
+from crosshair.libimpl.builtinslib import SymbolicInt
 from crosshair.options import DEFAULT_OPTIONS, AnalysisOptionSet
 from crosshair.statespace import (
     CANNOT_CONFIRM,
@@ -705,6 +706,13 @@ def signaling_alarm(self, air_samples: List[int]) -> bool:
             )
         )
 
+    def test_newtype(self) -> None:
+        T = TypeVar("T")
+        Number = NewType("Number", int)
+        with standalone_statespace:
+            x = proxy_for_type(Number, "x", allow_subtypes=False)
+        assert isinstance(x, SymbolicInt)
+
     def test_container_typevar(self) -> None:
         T = TypeVar("T")