Fix crash on TypeGuard plus "and" (#10496)

In python/typeshed#5473, I tried to switch a number of `inspect` functions to use the new `TypeGuard` functionality. Unfortunately, mypy-primer found a number of crashes in third-party libraries in places where a TypeGuard function was ANDed together with some other check. Examples:

- https://github.com/sphinx-doc/sphinx/blob/4.x/sphinx/util/inspect.py#L252
- https://github.com/sphinx-doc/sphinx/blob/4.x/sphinx/ext/coverage.py#L212
- https://github.com/streamlit/streamlit/blob/develop/lib/streamlit/elements/doc_string.py#L105

The problems trace back to the decision in #9865 to make TypeGuardType not inherit from ProperType: in various conditions that are more complicated than a simple `if` check, mypy wants everything to become a ProperType. Therefore, to fix the crashes I had to make TypeGuardType a ProperType and support it in various visitors.

mypy/constraints.py

@@ -7,7 +7,7 @@
  CallableType, Type, TypeVisitor, UnboundType, AnyType, NoneType, TypeVarType, Instance,
  TupleType, TypedDictType, UnionType, Overloaded, ErasedType, PartialType, DeletedType,
  UninhabitedType, TypeType, TypeVarId, TypeQuery, is_named_instance, TypeOfAny, LiteralType,
- ProperType, get_proper_type, TypeAliasType
+ ProperType, get_proper_type, TypeAliasType, TypeGuardType
 )
 from mypy.maptype import map_instance_to_supertype
 import mypy.subtypes
@@ -534,6 +534,9 @@ def visit_union_type(self, template: UnionType) -> List[Constraint]:
  def visit_type_alias_type(self, template: TypeAliasType) -> List[Constraint]:
  assert False, "This should be never called, got {}".format(template)
 
+ def visit_type_guard_type(self, template: TypeGuardType) -> List[Constraint]:
+ assert False, "This should be never called, got {}".format(template)
+
  def infer_against_any(self, types: Iterable[Type], any_type: AnyType) -> List[Constraint]:
  res = [] # type: List[Constraint]
  for t in types:

mypy/erasetype.py

@@ -4,7 +4,7 @@
  Type, TypeVisitor, UnboundType, AnyType, NoneType, TypeVarId, Instance, TypeVarType,
  CallableType, TupleType, TypedDictType, UnionType, Overloaded, ErasedType, PartialType,
  DeletedType, TypeTranslator, UninhabitedType, TypeType, TypeOfAny, LiteralType, ProperType,
- get_proper_type, TypeAliasType
+ get_proper_type, TypeAliasType, TypeGuardType
 )
 from mypy.nodes import ARG_STAR, ARG_STAR2
 
@@ -90,6 +90,9 @@ def visit_union_type(self, t: UnionType) -> ProperType:
  from mypy.typeops import make_simplified_union
  return make_simplified_union(erased_items)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> ProperType:
+ return TypeGuardType(t.type_guard.accept(self))
+
  def visit_type_type(self, t: TypeType) -> ProperType:
  return TypeType.make_normalized(t.item.accept(self), line=t.line)
 

mypy/expandtype.py

@@ -1,7 +1,7 @@
 from typing import Dict, Iterable, List, TypeVar, Mapping, cast
 
 from mypy.types import (
- Type, Instance, CallableType, TypeVisitor, UnboundType, AnyType,
+ Type, Instance, CallableType, TypeGuardType, TypeVisitor, UnboundType, AnyType,
  NoneType, TypeVarType, Overloaded, TupleType, TypedDictType, UnionType,
  ErasedType, PartialType, DeletedType, UninhabitedType, TypeType, TypeVarId,
  FunctionLike, TypeVarDef, LiteralType, get_proper_type, ProperType,
@@ -126,6 +126,9 @@ def visit_union_type(self, t: UnionType) -> Type:
  from mypy.typeops import make_simplified_union # asdf
  return make_simplified_union(self.expand_types(t.items), t.line, t.column)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> ProperType:
+ return TypeGuardType(t.type_guard.accept(self))
+
  def visit_partial_type(self, t: PartialType) -> Type:
  return t
 

mypy/fixup.py

@@ -9,7 +9,7 @@
  TypeVarExpr, ClassDef, Block, TypeAlias,
 )
 from mypy.types import (
- CallableType, Instance, Overloaded, TupleType, TypedDictType,
+ CallableType, Instance, Overloaded, TupleType, TypeGuardType, TypedDictType,
  TypeVarType, UnboundType, UnionType, TypeVisitor, LiteralType,
  TypeType, NOT_READY, TypeAliasType, AnyType, TypeOfAny, TypeVarDef
 )
@@ -254,6 +254,9 @@ def visit_union_type(self, ut: UnionType) -> None:
  for it in ut.items:
  it.accept(self)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> None:
+ t.type_guard.accept(self)
+
  def visit_void(self, o: Any) -> None:
  pass # Nothing to descend into.
 

mypy/indirection.py

@@ -97,6 +97,9 @@ def visit_literal_type(self, t: types.LiteralType) -> Set[str]:
  def visit_union_type(self, t: types.UnionType) -> Set[str]:
  return self._visit(t.items)
 
+ def visit_type_guard_type(self, t: types.TypeGuardType) -> Set[str]:
+ return self._visit(t.type_guard)
+
  def visit_partial_type(self, t: types.PartialType) -> Set[str]:
  return set()
 

mypy/join.py

@@ -7,7 +7,7 @@
  Type, AnyType, NoneType, TypeVisitor, Instance, UnboundType, TypeVarType, CallableType,
  TupleType, TypedDictType, ErasedType, UnionType, FunctionLike, Overloaded, LiteralType,
  PartialType, DeletedType, UninhabitedType, TypeType, TypeOfAny, get_proper_type,
- ProperType, get_proper_types, TypeAliasType, PlaceholderType
+ ProperType, get_proper_types, TypeAliasType, PlaceholderType, TypeGuardType
 )
 from mypy.maptype import map_instance_to_supertype
 from mypy.subtypes import (
@@ -340,6 +340,9 @@ def visit_type_type(self, t: TypeType) -> ProperType:
  def visit_type_alias_type(self, t: TypeAliasType) -> ProperType:
  assert False, "This should be never called, got {}".format(t)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> ProperType:
+ assert False, "This should be never called, got {}".format(t)
+
  def join(self, s: Type, t: Type) -> ProperType:
  return join_types(s, t)
 

mypy/meet.py

@@ -8,7 +8,7 @@
  Type, AnyType, TypeVisitor, UnboundType, NoneType, TypeVarType, Instance, CallableType,
  TupleType, TypedDictType, ErasedType, UnionType, PartialType, DeletedType,
  UninhabitedType, TypeType, TypeOfAny, Overloaded, FunctionLike, LiteralType,
- ProperType, get_proper_type, get_proper_types, TypeAliasType
+ ProperType, get_proper_type, get_proper_types, TypeAliasType, TypeGuardType
 )
 from mypy.subtypes import is_equivalent, is_subtype, is_callable_compatible, is_proper_subtype
 from mypy.erasetype import erase_type
@@ -648,6 +648,9 @@ def visit_type_type(self, t: TypeType) -> ProperType:
  def visit_type_alias_type(self, t: TypeAliasType) -> ProperType:
  assert False, "This should be never called, got {}".format(t)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> ProperType:
+ assert False, "This should be never called, got {}".format(t)
+
  def meet(self, s: Type, t: Type) -> ProperType:
  return meet_types(s, t)
 

mypy/sametypes.py

@@ -1,7 +1,7 @@
 from typing import Sequence
 
 from mypy.types import (
- Type, UnboundType, AnyType, NoneType, TupleType, TypedDictType,
+ Type, TypeGuardType, UnboundType, AnyType, NoneType, TupleType, TypedDictType,
  UnionType, CallableType, TypeVarType, Instance, TypeVisitor, ErasedType,
  Overloaded, PartialType, DeletedType, UninhabitedType, TypeType, LiteralType,
  ProperType, get_proper_type, TypeAliasType)
@@ -10,6 +10,7 @@
 
 def is_same_type(left: Type, right: Type) -> bool:
  """Is 'left' the same type as 'right'?"""
+
  left = get_proper_type(left)
  right = get_proper_type(right)
 
@@ -150,6 +151,12 @@ def visit_union_type(self, left: UnionType) -> bool:
  else:
  return False
 
+ def visit_type_guard_type(self, left: TypeGuardType) -> bool:
+ if isinstance(self.right, TypeGuardType):
+ return is_same_type(left.type_guard, self.right.type_guard)
+ else:
+ return False
+
  def visit_overloaded(self, left: Overloaded) -> bool:
  if isinstance(self.right, Overloaded):
  return is_same_types(left.items(), self.right.items())

mypy/server/astdiff.py

@@ -57,7 +57,7 @@ class level -- these are handled at attribute level (say, 'mod.Cls.method'
  FuncBase, OverloadedFuncDef, FuncItem, MypyFile, UNBOUND_IMPORTED
 )
 from mypy.types import (
- Type, TypeVisitor, UnboundType, AnyType, NoneType, UninhabitedType,
+ Type, TypeGuardType, TypeVisitor, UnboundType, AnyType, NoneType, UninhabitedType,
  ErasedType, DeletedType, Instance, TypeVarType, CallableType, TupleType, TypedDictType,
  UnionType, Overloaded, PartialType, TypeType, LiteralType, TypeAliasType
 )
@@ -335,6 +335,9 @@ def visit_union_type(self, typ: UnionType) -> SnapshotItem:
  normalized = tuple(sorted(items))
  return ('UnionType', normalized)
 
+ def visit_type_guard_type(self, typ: TypeGuardType) -> SnapshotItem:
+ return ('TypeGuardType', snapshot_type(typ.type_guard))
+
  def visit_overloaded(self, typ: Overloaded) -> SnapshotItem:
  return ('Overloaded', snapshot_types(typ.items()))
 

mypy/server/astmerge.py

@@ -59,7 +59,7 @@
  Type, SyntheticTypeVisitor, Instance, AnyType, NoneType, CallableType, ErasedType, DeletedType,
  TupleType, TypeType, TypeVarType, TypedDictType, UnboundType, UninhabitedType, UnionType,
  Overloaded, TypeVarDef, TypeList, CallableArgument, EllipsisType, StarType, LiteralType,
- RawExpressionType, PartialType, PlaceholderType, TypeAliasType
+ RawExpressionType, PartialType, PlaceholderType, TypeAliasType, TypeGuardType
 )
 from mypy.util import get_prefix, replace_object_state
 from mypy.typestate import TypeState
@@ -389,6 +389,9 @@ def visit_erased_type(self, t: ErasedType) -> None:
  def visit_deleted_type(self, typ: DeletedType) -> None:
  pass
 
+ def visit_type_guard_type(self, typ: TypeGuardType) -> None:
+ raise RuntimeError
+
  def visit_partial_type(self, typ: PartialType) -> None:
  raise RuntimeError
 

mypy/server/deps.py

@@ -97,7 +97,8 @@ class 'mod.Cls'. This can also refer to an attribute inherited from a
  Type, Instance, AnyType, NoneType, TypeVisitor, CallableType, DeletedType, PartialType,
  TupleType, TypeType, TypeVarType, TypedDictType, UnboundType, UninhabitedType, UnionType,
  FunctionLike, Overloaded, TypeOfAny, LiteralType, ErasedType, get_proper_type, ProperType,
- TypeAliasType)
+ TypeAliasType, TypeGuardType
+)
 from mypy.server.trigger import make_trigger, make_wildcard_trigger
 from mypy.util import correct_relative_import
 from mypy.scope import Scope
@@ -970,6 +971,9 @@ def visit_unbound_type(self, typ: UnboundType) -> List[str]:
  def visit_uninhabited_type(self, typ: UninhabitedType) -> List[str]:
  return []
 
+ def visit_type_guard_type(self, typ: TypeGuardType) -> List[str]:
+ return typ.type_guard.accept(self)
+
  def visit_union_type(self, typ: UnionType) -> List[str]:
  triggers = []
  for item in typ.items:

mypy/subtypes.py

@@ -4,7 +4,7 @@
 from typing_extensions import Final
 
 from mypy.types import (
- Type, AnyType, UnboundType, TypeVisitor, FormalArgument, NoneType,
+ Type, AnyType, TypeGuardType, UnboundType, TypeVisitor, FormalArgument, NoneType,
  Instance, TypeVarType, CallableType, TupleType, TypedDictType, UnionType, Overloaded,
  ErasedType, PartialType, DeletedType, UninhabitedType, TypeType, is_named_instance,
  FunctionLike, TypeOfAny, LiteralType, get_proper_type, TypeAliasType
@@ -475,6 +475,9 @@ def visit_overloaded(self, left: Overloaded) -> bool:
  def visit_union_type(self, left: UnionType) -> bool:
  return all(self._is_subtype(item, self.orig_right) for item in left.items)
 
+ def visit_type_guard_type(self, left: TypeGuardType) -> bool:
+ raise RuntimeError("TypeGuard should not appear here")
+
  def visit_partial_type(self, left: PartialType) -> bool:
  # This is indeterminate as we don't really know the complete type yet.
  raise RuntimeError
@@ -1374,6 +1377,14 @@ def visit_overloaded(self, left: Overloaded) -> bool:
  def visit_union_type(self, left: UnionType) -> bool:
  return all([self._is_proper_subtype(item, self.orig_right) for item in left.items])
 
+ def visit_type_guard_type(self, left: TypeGuardType) -> bool:
+ if isinstance(self.right, TypeGuardType):
+ # TypeGuard[bool] is a subtype of TypeGuard[int]
+ return self._is_proper_subtype(left.type_guard, self.right.type_guard)
+ else:
+ # TypeGuards aren't a subtype of anything else for now (but see #10489)
+ return False
+
  def visit_partial_type(self, left: PartialType) -> bool:
  # TODO: What's the right thing to do here?
  return False

mypy/type_visitor.py

@@ -19,7 +19,7 @@
 T = TypeVar('T')
 
 from mypy.types import (
- Type, AnyType, CallableType, Overloaded, TupleType, TypedDictType, LiteralType,
+ Type, AnyType, CallableType, Overloaded, TupleType, TypeGuardType, TypedDictType, LiteralType,
  RawExpressionType, Instance, NoneType, TypeType,
  UnionType, TypeVarType, PartialType, DeletedType, UninhabitedType, TypeVarLikeDef,
  UnboundType, ErasedType, StarType, EllipsisType, TypeList, CallableArgument,
@@ -103,6 +103,10 @@ def visit_type_type(self, t: TypeType) -> T:
  def visit_type_alias_type(self, t: TypeAliasType) -> T:
  pass
 
+ @abstractmethod
+ def visit_type_guard_type(self, t: TypeGuardType) -> T:
+ pass
+
 
 @trait
 @mypyc_attr(allow_interpreted_subclasses=True)
@@ -220,6 +224,9 @@ def visit_union_type(self, t: UnionType) -> Type:
  def translate_types(self, types: Iterable[Type]) -> List[Type]:
  return [t.accept(self) for t in types]
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> Type:
+ return TypeGuardType(t.type_guard.accept(self))
+
  def translate_variables(self,
  variables: Sequence[TypeVarLikeDef]) -> Sequence[TypeVarLikeDef]:
  return variables
@@ -319,6 +326,9 @@ def visit_star_type(self, t: StarType) -> T:
  def visit_union_type(self, t: UnionType) -> T:
  return self.query_types(t.items)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> T:
+ return t.type_guard.accept(self)
+
  def visit_overloaded(self, t: Overloaded) -> T:
  return self.query_types(t.items())
 

mypy/typeanal.py

@@ -14,7 +14,7 @@
 from mypy.types import (
  Type, UnboundType, TypeVarType, TupleType, TypedDictType, UnionType, Instance, AnyType,
  CallableType, NoneType, ErasedType, DeletedType, TypeList, TypeVarDef, SyntheticTypeVisitor,
- StarType, PartialType, EllipsisType, UninhabitedType, TypeType,
+ StarType, PartialType, EllipsisType, UninhabitedType, TypeType, TypeGuardType,
  CallableArgument, TypeQuery, union_items, TypeOfAny, LiteralType, RawExpressionType,
  PlaceholderType, Overloaded, get_proper_type, TypeAliasType, TypeVarLikeDef, ParamSpecDef
 )
@@ -542,6 +542,9 @@ def visit_callable_type(self, t: CallableType, nested: bool = True) -> Type:
  )
  return ret
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> Type:
+ return t
+
  def anal_type_guard(self, t: Type) -> Optional[Type]:
  if isinstance(t, UnboundType):
  sym = self.lookup_qualified(t.name, t)

mypy/types.py

@@ -270,7 +270,14 @@ def copy_modified(self, *,
  self.line, self.column)
 
 
-class TypeGuardType(Type):
+class ProperType(Type):
+ """Not a type alias.
+
+ Every type except TypeAliasType must inherit from this type.
+ """
+
+
+class TypeGuardType(ProperType):
  """Only used by find_instance_check() etc."""
  def __init__(self, type_guard: Type):
  super().__init__(line=type_guard.line, column=type_guard.column)
@@ -279,12 +286,8 @@ def __init__(self, type_guard: Type):
  def __repr__(self) -> str:
  return "TypeGuard({})".format(self.type_guard)
 
-
-class ProperType(Type):
- """Not a type alias.
-
- Every type except TypeAliasType must inherit from this type.
- """
+ def accept(self, visitor: 'TypeVisitor[T]') -> T:
+ return visitor.visit_type_guard_type(self)
 
 
 class TypeVarId:
@@ -2183,6 +2186,9 @@ def visit_union_type(self, t: UnionType) -> str:
  s = self.list_str(t.items)
  return 'Union[{}]'.format(s)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> str:
+ return 'TypeGuard[{}]'.format(t.type_guard.accept(self))
+
  def visit_partial_type(self, t: PartialType) -> str:
  if t.type is None:
  return '<partial None>'

mypy/typetraverser.py

@@ -6,7 +6,7 @@
  Type, SyntheticTypeVisitor, AnyType, UninhabitedType, NoneType, ErasedType, DeletedType,
  TypeVarType, LiteralType, Instance, CallableType, TupleType, TypedDictType, UnionType,
  Overloaded, TypeType, CallableArgument, UnboundType, TypeList, StarType, EllipsisType,
- PlaceholderType, PartialType, RawExpressionType, TypeAliasType
+ PlaceholderType, PartialType, RawExpressionType, TypeAliasType, TypeGuardType
 )
 
 
@@ -62,6 +62,9 @@ def visit_typeddict_type(self, t: TypedDictType) -> None:
  def visit_union_type(self, t: UnionType) -> None:
  self.traverse_types(t.items)
 
+ def visit_type_guard_type(self, t: TypeGuardType) -> None:
+ t.type_guard.accept(self)
+
  def visit_overloaded(self, t: Overloaded) -> None:
  self.traverse_types(t.items())
 

test-data/unit/check-typeguard.test

@@ -294,3 +294,24 @@ class C:
 class D(C):
  def is_float(self, a: object) -> bool: pass # E: Signature of "is_float" incompatible with supertype "C"
 [builtins fixtures/tuple.pyi]
+
+[case testTypeGuardInAnd]
+from typing import Any
+from typing_extensions import TypeGuard
+import types
+def isclass(a: object) -> bool:
+ pass
+def ismethod(a: object) -> TypeGuard[float]:
+ pass
+def isfunction(a: object) -> TypeGuard[str]:
+ pass
+def isclassmethod(obj: Any) -> bool:
+ if ismethod(obj) and obj.__self__ is not None and isclass(obj.__self__): # E: "float" has no attribute "__self__"
+ return True
+
+ return False
+def coverage(obj: Any) -> bool:
+ if not (ismethod(obj) or isfunction(obj)):
+ return True
+ return False
+[builtins fixtures/classmethod.pyi]