Fix false positive error when calling an UnboundMethodValue (#548)

docs/changelog.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Fix false positive error certain method calls on literals (#548)
 - Preserve `Annotated` annotations on access to methods of
   literals (#541)
 - `allow_call` callables are now also called if the arguments

pyanalyze/test_attributes.py

@@ -351,3 +351,15 @@ def capybara(x: Union[A, B]):
             if hasattr(x, "a") and hasattr(x, "b"):
                 assert_is_value(x.a, AnyValue(AnySource.inference))
                 assert_is_value(x.b, AnyValue(AnySource.inference))
+
+    @assert_passes()
+    def test_hasattr_plus_call(self):
+        class X:
+            @classmethod
+            def types(cls):
+                return []
+
+        def capybara(x: X) -> None:
+            cls = X
+            if hasattr(cls, "types"):  # E: value_always_true
+                assert_is_value(cls.types(), AnyValue(AnySource.unannotated))

pyanalyze/value.py

@@ -21,7 +21,6 @@ def function(x: int, y: list[int], z: Any):
 
 import collections.abc
 import enum
-import inspect
 import textwrap
 from collections import deque, OrderedDict
 from dataclasses import dataclass, field, InitVar
@@ -544,17 +543,20 @@ class UnboundMethodValue(Value):
     def get_method(self) -> Optional[Any]:
         """Return the runtime callable for this ``UnboundMethodValue``, or
         None if it cannot be found."""
+        root = self.composite.value
+        if isinstance(root, AnnotatedValue):
+            root = root.value
+        if isinstance(root, KnownValue):
+            typ = root.val
+        else:
+            typ = root.get_type()
         try:
-            typ = self.composite.value.get_type()
             method = getattr(typ, self.attr_name)
             if self.secondary_attr_name is not None:
                 method = getattr(method, self.secondary_attr_name)
-            # don't use unbound methods in py2
-            if inspect.ismethod(method) and method.__self__ is None:
-                method = method.__func__
-            return method
         except AttributeError:
             return None
+        return method
 
     def is_type(self, typ: type) -> bool:
         return isinstance(self.get_method(), typ)