CR fixes (partial)

Author: pkch

mypy/expandtype.py

@@ -7,8 +7,6 @@
     FunctionLike, TypeVarDef
 )
 
-import mypy
-
 
 def expand_type(typ: Type, env: Mapping[TypeVarId, Type]) -> Type:
     """Substitute any type variable references in a type given by a type

mypy/typeanal.py

@@ -240,6 +240,8 @@ def visit_unbound_type(self, t: UnboundType) -> Type:
                 return t
             info = sym.node  # type: TypeInfo
             if info.fullname() == 'builtins.tuple':
+                # tuple[int] or tuple[int, ...] are invalid
+                # The naked tuple should use canonical representation with type argument Any
                 assert not t.args
                 return Instance(info, self.anal_array([AnyType()]), t.line, t.column)
             else:
@@ -633,11 +635,6 @@ def visit_callable_type(self, t: CallableType) -> None:
     def visit_tuple_type(self, t: TupleType) -> None:
         for item in t.items:
             item.accept(self)
-        # if it's not builtins.tuple, then its bases should have tuple[Any]
-        # TODO: put assert here if it's not too slow
-        if isinstance(t.fallback, Instance) and t.fallback.type.fullname() == 'builtins.tuple':
-            fallback_item = UnionType.make_simplified_union(t.items)
-            t.fallback.args = [fallback_item]
 
     def visit_typeddict_type(self, t: TypedDictType) -> None:
         for item_type in t.items.values():

mypy/types.py

@@ -1496,7 +1496,7 @@ def visit_tuple_type(self, t: TupleType) -> str:
         s = self.list_str(t.items)
         if t.fallback and t.fallback.type:
             fallback_name = t.fallback.type.fullname()
-            if fallback_name not in ('builtins.tuple', 'builtins.object'):
+            if fallback_name != 'builtins.tuple':
                 return 'Tuple[{}, fallback={}]'.format(s, t.fallback.accept(self))
         return 'Tuple[{}]'.format(s)
 
@@ -1747,9 +1747,7 @@ def set_typ_args(tp: Type, new_args: List[Type], line: int = -1, column: int = -
     if isinstance(tp, Instance):
         return Instance(tp.type, new_args, line, column)
     if isinstance(tp, TupleType):
-        fallback_args = [UnionType.make_simplified_union(new_args)]
-        fallback = tp.fallback.copy_modified(args=fallback_args)
-        return tp.copy_modified(items=new_args, fallback=fallback)
+        return tp.copy_modified(items=new_args)
     if isinstance(tp, UnionType):
         return UnionType(new_args, line, column)
     if isinstance(tp, CallableType):

test-data/unit/check-tuples.test

@@ -604,10 +604,10 @@ b = s in t
 
 [file builtins.py]
 from typing import TypeVar, Generic
-_T = TypeVar('_T')
+_T_co = TypeVar('_T_co', covariant=True)
 class object:
     def __init__(self) -> None: pass
-class tuple(Generic[_T]):
+class tuple(Generic[_T_co]):
     def __len__(self) -> int: pass
     def __str__(self) -> str: pass
     def __contains__(self, o: object) -> bool: pass

test-data/unit/fixtures/callable.pyi

@@ -1,14 +1,14 @@
 from typing import Generic, Tuple, TypeVar, Union
 
-T = TypeVar('T')
+T_co = TypeVar('T_co', covariant=True)
 
 class object:
     def __init__(self) -> None: pass
 
 class type:
     def __init__(self, x) -> None: pass
 
-class tuple(Generic[T]): pass
+class tuple(Generic[T_co]): pass
 
 class function: pass
 

test-data/unit/fixtures/f_string.pyi

@@ -5,6 +5,8 @@ from typing import TypeVar, Generic, Iterable, Iterator, List, overload
 
 T = TypeVar('T')
 
+T_co = TypeVar('T_co', covariant=True)
+
 class object:
     def __init__(self): pass
 
@@ -20,7 +22,7 @@ class list(Iterable[T], Generic[T]):
     def __init__(self, x: Iterable[T]) -> None: pass
     def append(self, x: T) -> None: pass
 
-class tuple(Generic[T]): pass
+class tuple(Generic[T_co]): pass
 
 class function: pass
 class int:

test-data/unit/fixtures/isinstance.pyi

@@ -1,14 +1,14 @@
 from typing import Tuple, TypeVar, Generic, Union
 
-T = TypeVar('T')
+T_co = TypeVar('T_co', covariant=True)
 
 class object:
     def __init__(self) -> None: pass
 
 class type:
     def __init__(self, x) -> None: pass
 
-class tuple(Generic[T]): pass
+class tuple(Generic[T_co]): pass
 
 class function: pass
 

test-data/unit/fixtures/list.pyi

@@ -23,7 +23,7 @@ class list(Iterable[T], Generic[T]):
     def extend(self, x: Iterable[T]) -> None: pass
 
 _T_co = TypeVar('_T_co', covariant=True)
-class tuple(Sequence[_T_co], Generic[_T_co]): pass
+class tuple(Generic[_T_co]): pass
 class function: pass
 class int: pass
 class float: pass