Fix tests

mypy/test/testsolve.py

@@ -64,13 +64,13 @@ def test_multiple_variables(self) -> None:
     def test_no_constraints_for_var(self) -> None:
         self.assert_solve([self.fx.t.id],
                           [],
-                          [self.fx.nonet])
+                          [self.fx.uninhabited])
         self.assert_solve([self.fx.t.id, self.fx.s.id],
                           [],
-                          [self.fx.nonet, self.fx.nonet])
+                          [self.fx.uninhabited, self.fx.uninhabited])
         self.assert_solve([self.fx.t.id, self.fx.s.id],
                           [self.supc(self.fx.s, self.fx.a)],
-                          [self.fx.nonet, (self.fx.a, self.fx.o)])
+                          [self.fx.uninhabited, (self.fx.a, self.fx.o)])
 
     def test_simple_constraints_with_dynamic_type(self) -> None:
         self.assert_solve([self.fx.t.id],

mypy/test/testsubtypes.py

@@ -84,8 +84,8 @@ def test_basic_callable_subtyping(self) -> None:
         self.assert_strict_subtype(self.fx.callable(self.fx.d, self.fx.b),
                                    self.fx.callable(self.fx.d, self.fx.a))
 
-        self.assert_unrelated(self.fx.callable(self.fx.a, self.fx.a),
-                              self.fx.callable(self.fx.a, self.fx.nonet))
+        self.assert_strict_subtype(self.fx.callable(self.fx.a, self.fx.nonet),
+                                   self.fx.callable(self.fx.a, self.fx.a))
 
         self.assert_unrelated(
             self.fx.callable(self.fx.a, self.fx.a, self.fx.a),

mypy/typefixture.py

@@ -7,7 +7,7 @@
 
 from mypy.types import (
     Type, TypeVarType, AnyType, ErrorType, NoneTyp,
-    Instance, CallableType, TypeVarDef, TypeType,
+    Instance, CallableType, TypeVarDef, TypeType, UninhabitedType
 )
 from mypy.nodes import (
     TypeInfo, ClassDef, Block, ARG_POS, ARG_OPT, ARG_STAR, SymbolTable,
@@ -43,6 +43,7 @@ def make_type_var(name: str, id: int, values: List[Type], upper_bound: Type,
         self.anyt = AnyType()
         self.err = ErrorType()
         self.nonet = NoneTyp()
+        self.uninhabited = UninhabitedType()
 
         # Abstract class TypeInfos
 

mypy/types.py

@@ -1412,7 +1412,8 @@ def visit_callable_type(self, t: CallableType) -> str:
 
         s = '({})'.format(s)
 
-        s += ' -> {}'.format(t.ret_type)
+        if not isinstance(t.ret_type, NoneTyp):
+            s += ' -> {}'.format(t.ret_type)
 
         if t.variables:
             s = '{} {}'.format(t.variables, s)

test-data/unit/check-async-await.test

@@ -282,7 +282,7 @@ class C:
     def __aenter__(self) -> None: pass
     async def __aexit__(self, x, y, z) -> None: pass
 async def f() -> None:
-    async with C() as x:  # E: "__aenter__" of "C" does not return a value
+    async with C() as x:  # E: None has no attribute "__await__"
         pass
 [builtins fixtures/async_await.pyi]
 [out]
@@ -304,7 +304,7 @@ class C:
     async def __aenter__(self) -> int: pass
     def __aexit__(self, x, y, z) -> None: pass
 async def f() -> None:
-    async with C() as x: # E: "__aexit__" of "C" does not return a value
+    async with C() as x: # E: None has no attribute "__await__"
         pass
 [builtins fixtures/async_await.pyi]
 [out]

test-data/unit/check-bound.test

@@ -56,7 +56,7 @@ class C(Generic[T]):
         return self.t
 c1 = None # type: C[None]
 c1.get()
-d = c1.get() # E: Function does not return a value
+d = c1.get() # E: "get" of "C" does not return a value
 
 
 [case testBoundAny]
@@ -82,7 +82,7 @@ def f(g: Callable[[], T]) -> T:
     return g()
 def h() -> None: pass
 f(h)
-a = f(h) # E: "h" does not return a value
+a = f(h) # E: "f" does not return a value
 
 
 [case testBoundInheritance]

test-data/unit/check-classes.test

@@ -281,10 +281,9 @@ class A:
     def g(self) -> 'A': pass
 class B(A):
     def f(self) -> A: pass  # Fail
-    def g(self) -> None: pass  # Fail
+    def g(self) -> None: pass
 [out]
 main:6: error: Return type of "f" incompatible with supertype "A"
-main:7: error: Return type of "g" incompatible with supertype "A"
 
 [case testOverride__new__WithDifferentSignature]
 class A:
@@ -727,12 +726,9 @@ import typing
 class A:
     def f(self) -> None:
         def g() -> None:
-            a = None
-        b = None
+            "" + 1  # E: Unsupported operand types for + ("str" and "int")
+        "" + 1  # E: Unsupported operand types for + ("str" and "int")
 [out]
-main:5: error: Need type annotation for variable
-main:6: error: Need type annotation for variable
-
 
 -- Static methods
 -- --------------

test-data/unit/check-dynamic-typing.test

@@ -537,7 +537,7 @@ f11 = None # type: Callable[[], Any]
 f2 = None # type: Callable[[], A]
 f3 = None # type: Callable[[], None]
 
-f2 = f3 # E: Incompatible types in assignment (expression has type Callable[[], None], variable has type Callable[[], A])
+f2 = f3
 
 f1 = f2
 f1 = f3

test-data/unit/check-expressions.test

@@ -921,8 +921,8 @@ a = None # type: A
 f() + a     # E: "f" does not return a value
 a + f()     # E: "f" does not return a value
 f() == a    # E: "f" does not return a value
-a != f()    # E: Unsupported left operand type for != ("A")
-cast(A, f()) # E: "f" does not return a value
+a != f()    # E: "f" does not return a value
+cast(A, f())
 f().foo     # E: "f" does not return a value
 
 def f() -> None: pass
@@ -933,9 +933,9 @@ class A:
 [case testNoneReturnTypeWithExpressions2]
 
 a, b = None, None # type: (A, bool)
-a < f()    # E: Unsupported left operand type for < ("A")
+f() in a
+a < f()    # E: "f" does not return a value
 f() <= a   # E: "f" does not return a value
-f() in a   # E: Unsupported right operand type for in ("A")
 a in f()   # E: "f" does not return a value
 -f()       # E: "f" does not return a value
 not f()    # E: "f" does not return a value
@@ -947,6 +947,9 @@ class A:
     def __add__(self, x: 'A') -> 'A':
         pass
 [builtins fixtures/bool.pyi]
+[out]
+main:3: error: "f" does not return a value
+main:3: error: Unsupported right operand type for in ("A")
 
 
 -- Slicing
@@ -1458,6 +1461,7 @@ def f(x: int) -> None:
 [out]
 main:1: error: The return type of a generator function should be "Generator" or one of its supertypes
 main:2: error: Argument 1 to "f" has incompatible type "str"; expected "int"
+main:2: error: "f" does not return a value
 
 [case testYieldExpressionWithNone]
 from typing import Iterator
@@ -1471,14 +1475,14 @@ def f(x: int) -> Iterator[None]:
 -- ----------------
 
 
-[case testYieldFromIteratorHasNoValue]
+[case testYieldFromIteratorIsNone]
 from typing import Iterator
 def f() -> Iterator[int]:
     yield 5
 def g() -> Iterator[int]:
     a = yield from f()
+    reveal_type(a)  # E: Revealed type is 'builtins.None'
 [out]
-main:5: error: Function does not return a value
 
 [case testYieldFromGeneratorHasValue]
 from typing import Iterator, Generator

test-data/unit/check-functions.test

@@ -208,7 +208,7 @@ from typing import Callable
 f = None # type: Callable[[], None]
 g = None # type: Callable[[], object]
 f = g  # E: Incompatible types in assignment (expression has type Callable[[], object], variable has type Callable[[], None])
-g = f  # E: Incompatible types in assignment (expression has type Callable[[], None], variable has type Callable[[], object])
+g = f  # OK
 
 f = f
 g = g

test-data/unit/check-generic-subtyping.test

@@ -394,7 +394,7 @@ B(1)
 C(1)
 C('a')  # E: Argument 1 to "C" has incompatible type "str"; expected "int"
 D(A(1))
-D(1)  # E: Argument 1 to "D" has incompatible type "int"; expected A[None]
+D(1)  # E: Argument 1 to "D" has incompatible type "int"; expected A[<uninhabited>]
 
 
 [case testInheritedConstructor2]

test-data/unit/check-generics.test

@@ -565,7 +565,7 @@ def func(x: IntNode[T]) -> IntNode[T]:
     return x
 reveal_type(func) # E: Revealed type is 'def [T] (x: __main__.Node[builtins.int, T`-1]) -> __main__.Node[builtins.int, T`-1]'
 
-func(1) # E: Argument 1 to "func" has incompatible type "int"; expected Node[int, None]
+func(1) # E: Argument 1 to "func" has incompatible type "int"; expected Node[int, <uninhabited>]
 func(Node('x', 1)) # E: Argument 1 to "Node" has incompatible type "str"; expected "int"
 reveal_type(func(Node(1, 'x'))) # E: Revealed type is '__main__.Node[builtins.int, builtins.str*]'
 
@@ -800,7 +800,7 @@ reveal_type(x) # E: Revealed type is 'builtins.int'
 def f2(x: IntTP[T]) -> IntTP[T]:
     return x
 
-f2((1, 2, 3)) # E: Argument 1 to "f2" has incompatible type "Tuple[int, int, int]"; expected "Tuple[int, None]"
+f2((1, 2, 3)) # E: Argument 1 to "f2" has incompatible type "Tuple[int, int, int]"; expected "Tuple[int, <uninhabited>]"
 reveal_type(f2((1, 'x'))) # E: Revealed type is 'Tuple[builtins.int, builtins.str*]'
 
 [builtins fixtures/for.pyi]
@@ -869,7 +869,7 @@ n.y = 'x' # E: Incompatible types in assignment (expression has type "str", vari
 def f(x: Node[T, T]) -> TupledNode[T]:
     return Node(x.x, (x.x, x.x))
 
-f(1) # E: Argument 1 to "f" has incompatible type "int"; expected Node[None, None]
+f(1) # E: Argument 1 to "f" has incompatible type "int"; expected Node[<uninhabited>, <uninhabited>]
 f(Node(1, 'x')) # E: Cannot infer type argument 1 of "f"
 reveal_type(Node('x', 'x')) # E: Revealed type is 'a.Node[builtins.str*, builtins.str*]'
 

test-data/unit/check-inference-context.test

@@ -13,7 +13,7 @@ b = None # type: B
 
 ao = f()
 ab = f()
-b = f() # E: Incompatible types in assignment (expression has type A[None], variable has type "B")
+b = f() # E: Incompatible types in assignment (expression has type A[<uninhabited>], variable has type "B")
 
 def f() -> 'A[T]': pass
 
@@ -29,7 +29,7 @@ b = None # type: B
 
 ao = A()
 ab = A()
-b = A() # E: Incompatible types in assignment (expression has type A[None], variable has type "B")
+b = A() # E: Incompatible types in assignment (expression has type A[<uninhabited>], variable has type "B")
 
 class A(Generic[T]): pass
 class B: pass
@@ -334,7 +334,7 @@ aa = None # type: List[A]
 ao = None # type: List[object]
 a = None # type: A
 
-a = [] # E: Incompatible types in assignment (expression has type List[None], variable has type "A")
+a = [] # E: Incompatible types in assignment (expression has type List[<uninhabited>], variable has type "A")
 
 aa = []
 ao = []
@@ -385,7 +385,7 @@ class B(A): pass
 import typing
 def f() -> None:
     a = []     # E: Need type annotation for variable
-    b = [None]  # E: Need type annotation for variable
+    b = [None]
     c = [B()]
     c = [object()] # E: List item 0 has incompatible type "object"
     c = [B()]
@@ -755,7 +755,7 @@ T = TypeVar('T')
 def f(x: Union[List[T], str]) -> None: pass
 f([1])
 f('')
-f(1) # E: Argument 1 to "f" has incompatible type "int"; expected "Union[List[None], str]"
+f(1) # E: Argument 1 to "f" has incompatible type "int"; expected "Union[List[<uninhabited>], str]"
 [builtins fixtures/isinstancelist.pyi]
 
 [case testIgnoringInferenceContext]
@@ -824,7 +824,7 @@ from typing import TypeVar, Callable, Generic
 T = TypeVar('T')
 class A(Generic[T]):
     pass
-reveal_type(A()) # E: Revealed type is '__main__.A[builtins.None]'
+reveal_type(A()) # E: Revealed type is '__main__.A[<uninhabited>]'
 b = reveal_type(A())  # type: A[int] # E: Revealed type is '__main__.A[builtins.int]'
 
 [case testUnionWithGenericTypeItemContext]
@@ -877,4 +877,17 @@ class M(Generic[_KT, _VT]):
     def get(self, k: _KT, default: _T) -> _T: ...
 
 def f(d: M[_KT, _VT], k: _KT) -> _VT:
+    return d.get(k, None)  # E: "get" of "M" does not return a value
+
+[case testGenericMethodCalledInGenericContext2]
+from typing import TypeVar, Generic, Union
+
+_KT = TypeVar('_KT')
+_VT = TypeVar('_VT')
+_T = TypeVar('_T')
+
+class M(Generic[_KT, _VT]):
+    def get(self, k: _KT, default: _T) -> Union[_VT, _T]: ...
+
+def f(d: M[_KT, _VT], k: _KT) -> Union[_VT, None]:
     return d.get(k, None)