Forbid keyword arguments for certain Mapping methods (#15085)

Author: beauxq

stdlib/typing.pyi

@@ -762,6 +762,11 @@ class ValuesView(MappingView, Collection[_VT_co]):
     def __contains__(self, value: object) -> bool: ...
     def __iter__(self) -> Iterator[_VT_co]: ...
 
+# note for Mapping.get and MutableMapping.pop and MutableMapping.setdefault
+# In _collections_abc.py the parameters are positional-or-keyword,
+# but dict and types.MappingProxyType (the vast majority of Mapping types)
+# don't allow keyword arguments.
+
 class Mapping(Collection[_KT], Generic[_KT, _VT_co]):
     # TODO: We wish the key type could also be covariant, but that doesn't work,
     # see discussion in https://github.com/python/typing/pull/273.
@@ -771,9 +776,9 @@ class Mapping(Collection[_KT], Generic[_KT, _VT_co]):
     @overload
     def get(self, key: _KT, /) -> _VT_co | None: ...
     @overload
-    def get(self, key: _KT, /, default: _VT_co) -> _VT_co: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues] # Covariant type as parameter
+    def get(self, key: _KT, default: _VT_co, /) -> _VT_co: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues] # Covariant type as parameter
     @overload
-    def get(self, key: _KT, /, default: _T) -> _VT_co | _T: ...
+    def get(self, key: _KT, default: _T, /) -> _VT_co | _T: ...
     def items(self) -> ItemsView[_KT, _VT_co]: ...
     def keys(self) -> KeysView[_KT]: ...
     def values(self) -> ValuesView[_VT_co]: ...
@@ -789,9 +794,9 @@ class MutableMapping(Mapping[_KT, _VT]):
     @overload
     def pop(self, key: _KT, /) -> _VT: ...
     @overload
-    def pop(self, key: _KT, /, default: _VT) -> _VT: ...
+    def pop(self, key: _KT, default: _VT, /) -> _VT: ...
     @overload
-    def pop(self, key: _KT, /, default: _T) -> _VT | _T: ...
+    def pop(self, key: _KT, default: _T, /) -> _VT | _T: ...
     def popitem(self) -> tuple[_KT, _VT]: ...
     # This overload should be allowed only if the value type is compatible with None.
     #