fix: typing of pmap

pyrsistent/__init__.pyi

@@ -43,6 +43,10 @@ T = TypeVar('T')
 KT = TypeVar('KT')
 VT = TypeVar('VT')
 
+@overload
+def pmap(initial: Mapping[KT, VT] = {}, pre_size: int = 0) -> PMap[KT, VT]: ...
+@overload
+def pmap(initial: Iterable[Tuple[KT, VT]] = {}, pre_size: int = 0) -> PMap[KT, VT]: ...
 def pmap(initial: Union[Mapping[KT, VT], Iterable[Tuple[KT, VT]]] = {}, pre_size: int = 0) -> PMap[KT, VT]: ...
 def m(**kwargs: VT) -> PMap[str, VT]: ...
 

tests/typing_test.py

@@ -0,0 +1,6 @@
+# Check that the inferred types are as expected.
+
+from typing_extensions import assert_type
+from pyrsistent import PMap, pmap
+
+assert_type(pmap(dict[tuple[int, str], float]()), PMap[tuple[int, str], float])

tox.ini

@@ -25,6 +25,7 @@ commands = pytest
 deps =
     pytest
     hypothesis
+    typing_extensions
 
 # Specifying the following tests like this is very non-DRY but I have no better solution right now.
 [testenv:coverage-py38]