Uninhabited should have all attributes (python#19300)

Although this can hide some mypy bugs, TBH this always bothered me as
something conceptually wrong. The work on `checkmember` stuff inspired
me to actually try it.

Author: ilevkivskyi

mypy/checkexpr.py

@@ -1671,6 +1671,10 @@ def check_call(
                 object_type,
                 original_type=callee,
             )
+        elif isinstance(callee, UninhabitedType):
+            ret = UninhabitedType()
+            ret.ambiguous = callee.ambiguous
+            return callee, ret
         else:
             return self.msg.not_callable(callee, context), AnyType(TypeOfAny.from_error)
 

mypy/checkmember.py

@@ -69,6 +69,7 @@
     TypeVarLikeType,
     TypeVarTupleType,
     TypeVarType,
+    UninhabitedType,
     UnionType,
     get_proper_type,
 )
@@ -268,6 +269,10 @@ def _analyze_member_access(
         if not mx.suppress_errors:
             mx.msg.deleted_as_rvalue(typ, mx.context)
         return AnyType(TypeOfAny.from_error)
+    elif isinstance(typ, UninhabitedType):
+        attr_type = UninhabitedType()
+        attr_type.ambiguous = typ.ambiguous
+        return attr_type
     return report_missing_attribute(mx.original_type, typ, name, mx)
 
 

test-data/unit/check-unreachable-code.test

@@ -1587,3 +1587,19 @@ x = 0  # not unreachable
 
 f2: Callable[[], NoReturn] = lambda: foo()
 x = 0  # not unreachable
+
+[case testAttributeNoReturn]
+# flags: --warn-unreachable
+from typing import Optional, NoReturn, TypeVar
+
+def foo() -> NoReturn:
+    raise
+
+T = TypeVar("T")
+def bar(x: Optional[list[T]] = None) -> T:
+    ...
+
+reveal_type(bar().attr)  # N: Revealed type is "Never"
+1  # not unreachable
+reveal_type(foo().attr)  # N: Revealed type is "Never"
+1  # E: Statement is unreachable