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Set TypedDicts to always be their declared type as opposed to the type inferred when instantiated #2621

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Set TypedDicts to always be their declared type as opposed to the type inferred when instantiated #2621

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465bf00
Allow fields on a TypedDict to be subtypes of their declared types.
Dec 30, 2016
0ca0ae6
Take suggestion from Jukka to have calls to typed dicts always result…
Jan 6, 2017
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4 changes: 2 additions & 2 deletions mypy/checkexpr.py
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Original file line number Diff line number Diff line change
Expand Up @@ -246,12 +246,12 @@ def check_typeddict_call_with_kwargs(self, callee: TypedDictType,
for (item_name, item_expected_type) in callee.items.items():
item_value = kwargs[item_name]

item_actual_type = self.chk.check_simple_assignment(
self.chk.check_simple_assignment(
lvalue_type=item_expected_type, rvalue=item_value, context=item_value,
msg=messages.INCOMPATIBLE_TYPES,
lvalue_name='TypedDict item "{}"'.format(item_name),
rvalue_name='expression')
items[item_name] = item_actual_type
items[item_name] = item_expected_type

mapping_value_type = join.join_type_list(list(items.values()))
fallback = self.chk.named_generic_type('typing.Mapping',
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38 changes: 34 additions & 4 deletions test-data/unit/check-typeddict.test
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Expand Up @@ -136,6 +136,36 @@ def as_mapping(p: Point) -> Mapping[str, str]:
return p # E: Incompatible return value type (got "Point", expected Mapping[str, str])
[builtins fixtures/dict.pyi]

[case testTypedDictAcceptsIntForFloatDuckTypes]
from mypy_extensions import TypedDict
from typing import Any, Mapping
Point = TypedDict('Point', {'x': float, 'y': float})
def create_point() -> Point:
return Point(x=1, y=2)
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Can you also do something like reveal_type(Point(x=1, y=2)) in a test case?

[builtins fixtures/dict.pyi]

[case testTypedDictDoesNotAcceptsFloatForInt]
from mypy_extensions import TypedDict
from typing import Any, Mapping
Point = TypedDict('Point', {'x': int, 'y': int})
def create_point() -> Point:
return Point(x=1.2, y=2.5)
[out]
main:5: error: Incompatible types (expression has type "float", TypedDict item "x" has type "int")
main:5: error: Incompatible types (expression has type "float", TypedDict item "y" has type "int")
[builtins fixtures/dict.pyi]

[case testTypedDictAcceptsAnyType]
from mypy_extensions import TypedDict
from typing import Any, Mapping
Point = TypedDict('Point', {'x': float, 'y': float})
def create_point(something: Any) -> Point:
return Point({
'x': something.x,
'y': something.y
})
[builtins fixtures/dict.pyi]

-- TODO: Fix mypy stubs so that the following passes in the test suite
--[case testCanConvertTypedDictToAnySuperclassOfMapping]
--from mypy_extensions import TypedDict
Expand Down Expand Up @@ -191,9 +221,9 @@ CellWithObject = TypedDict('CellWithObject', {'value': object, 'meta': object})
c1 = CellWithInt(value=1, meta=42)
c2 = CellWithObject(value=2, meta='turtle doves')
joined_cells = [c1, c2]
reveal_type(c1) # E: Revealed type is 'TypedDict(value=builtins.int, meta=builtins.int, _fallback=typing.Mapping[builtins.str, builtins.int])'
reveal_type(c2) # E: Revealed type is 'TypedDict(value=builtins.int, meta=builtins.str, _fallback=typing.Mapping[builtins.str, builtins.object])'
reveal_type(joined_cells) # E: Revealed type is 'builtins.list[TypedDict(value=builtins.int, _fallback=typing.Mapping[builtins.str, builtins.int])]'
reveal_type(c1) # E: Revealed type is 'TypedDict(value=builtins.object, meta=builtins.int, _fallback=typing.Mapping[builtins.str, builtins.object])'
reveal_type(c2) # E: Revealed type is 'TypedDict(value=builtins.object, meta=builtins.object, _fallback=typing.Mapping[builtins.str, builtins.object])'
reveal_type(joined_cells) # E: Revealed type is 'builtins.list[TypedDict(value=builtins.object, _fallback=typing.Mapping[builtins.str, builtins.object])]'
[builtins fixtures/dict.pyi]

[case testJoinOfDisjointTypedDictsIsEmptyTypedDict]
Expand All @@ -204,7 +234,7 @@ d1 = Point(x=0, y=0)
d2 = Cell(value='pear tree')
joined_dicts = [d1, d2]
reveal_type(d1) # E: Revealed type is 'TypedDict(x=builtins.int, y=builtins.int, _fallback=typing.Mapping[builtins.str, builtins.int])'
reveal_type(d2) # E: Revealed type is 'TypedDict(value=builtins.str, _fallback=typing.Mapping[builtins.str, builtins.str])'
reveal_type(d2) # E: Revealed type is 'TypedDict(value=builtins.object, _fallback=typing.Mapping[builtins.str, builtins.object])'
reveal_type(joined_dicts) # E: Revealed type is 'builtins.list[TypedDict(_fallback=typing.Mapping[builtins.str, builtins.None])]'
[builtins fixtures/dict.pyi]

Expand Down