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Merged
merged 3 commits into from
Aug 21, 2022
Merged

Make sure ParamSpec suffix and arg kind do match #13468

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2b63e70
Make sure `ParamSpec` suffix and arg kind do match, refs #13460
sobolevn Aug 21, 2022
961559b
Use better error message
sobolevn Aug 21, 2022
d11e94e
Use better error message
sobolevn Aug 21, 2022
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8 changes: 6 additions & 2 deletions mypy/typeanal.py
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Original file line number Diff line number Diff line change
Expand Up @@ -838,17 +838,21 @@ def anal_type_guard_arg(self, t: UnboundType, fullname: str) -> Type | None:

def anal_star_arg_type(self, t: Type, kind: ArgKind, nested: bool) -> Type:
"""Analyze signature argument type for *args and **kwargs argument."""
# TODO: Check that suffix and kind match
if isinstance(t, UnboundType) and t.name and "." in t.name and not t.args:
components = t.name.split(".")
sym = self.lookup_qualified(".".join(components[:-1]), t)
tvar_name = ".".join(components[:-1])
sym = self.lookup_qualified(tvar_name, t)
if sym is not None and isinstance(sym.node, ParamSpecExpr):
tvar_def = self.tvar_scope.get_binding(sym)
if isinstance(tvar_def, ParamSpecType):
if kind == ARG_STAR:
make_paramspec = paramspec_args
if components[-1] != "args":
self.fail(f'Use "{tvar_name}.args" for variadic "*" parameter', t)
elif kind == ARG_STAR2:
make_paramspec = paramspec_kwargs
if components[-1] != "kwargs":
self.fail(f'Use "{tvar_name}.kwargs" for variadic "**" parameter', t)
else:
assert False, kind
return make_paramspec(
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15 changes: 15 additions & 0 deletions test-data/unit/check-parameter-specification.test
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Expand Up @@ -1112,3 +1112,18 @@ def func(callback: Callable[P, str]) -> Callable[P, str]:
return "foo"
return inner
[builtins fixtures/paramspec.pyi]

[case testParamSpecArgsAndKwargsMissmatch]
from typing import Callable
from typing_extensions import ParamSpec

P1 = ParamSpec("P1")

def func(callback: Callable[P1, str]) -> Callable[P1, str]:
def inner(
*args: P1.kwargs, # E: Use "P1.args" for variadic "*" parameter
**kwargs: P1.args, # E: Use "P1.kwargs" for variadic "**" parameter
) -> str:
return "foo"
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Maybe add some reveal_types here, as a sanity check to make sure that the typo doesn't cause mypy to make any incorrect inferences elsewhere?

Suggested change
return "foo"
reveal_type(args) # N: Revealed type is "builtins.tuple[builtins.object, ...]"
reveal_type(kwargs) # N: Revealed type is "builtins.dict[builtins.str, builtins.object]"
return "foo"

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This is not true:

main:11: note: Revealed type is "P1.args`-1"  (diff)
main:12: note: Revealed type is "P1.kwargs`-1" (diff)

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This is not true:

main:11: note: Revealed type is "P1.args`-1"  (diff)
main:12: note: Revealed type is "P1.kwargs`-1" (diff)

Oh, right. Maybe this, in that case?

Suggested change
return "foo"
a = args[0]
reveal_type(a) # N: Revealed type is "builtins.object"
for b, c in kwargs.items():
reveal_type(b) # N: Revealed type is "builtins.str"
reveal_type(c) # N: Revealed type is "builtins.object"
return "foo"

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@sobolevn sobolevn Aug 21, 2022 •
edited
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I think this is too much :)

No other tests do anything similar.

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Fair enough :)

return inner
[builtins fixtures/paramspec.pyi]