Add typing to Name._infer and AssignName.infer_lhs (#1651)

Co-authored-by: Marc Mueller <[email protected]>

astroid/inference.py

@@ -33,7 +33,11 @@
 )
 from astroid.interpreter import dunder_lookup
 from astroid.manager import AstroidManager
-from astroid.typing import InferenceErrorInfo, SuccessfulInferenceResult
+from astroid.typing import (
+    InferenceErrorInfo,
+    InferenceResult,
+    SuccessfulInferenceResult,
+)
 
 if TYPE_CHECKING:
     from astroid.objects import Property
@@ -185,7 +189,7 @@ def _infer_map(
 nodes.Dict._infer = infer_map  # type: ignore[assignment]
 
 
-def _higher_function_scope(node):
+def _higher_function_scope(node: nodes.NodeNG) -> nodes.FunctionDef | None:
     """Search for the first function which encloses the given
     scope. This can be used for looking up in that function's
     scope, in case looking up in a lower scope for a particular
@@ -201,11 +205,15 @@ def _higher_function_scope(node):
     while current.parent and not isinstance(current.parent, nodes.FunctionDef):
         current = current.parent
     if current and current.parent:
-        return current.parent
+        return current.parent  # type: ignore[return-value]
     return None
 
 
-def infer_name(self, context=None):
+def infer_name(
+    self: nodes.Name | nodes.AssignName,
+    context: InferenceContext | None = None,
+    **kwargs: Any,
+) -> Generator[InferenceResult, None, None]:
     """infer a Name: use name lookup rules"""
     frame, stmts = self.lookup(self.name)
     if not stmts:
@@ -225,7 +233,7 @@ def infer_name(self, context=None):
 
 
 # pylint: disable=no-value-for-parameter
-nodes.Name._infer = decorators.raise_if_nothing_inferred(
+nodes.Name._infer = decorators.raise_if_nothing_inferred(  # type: ignore[assignment]
     decorators.path_wrapper(infer_name)
 )
 nodes.AssignName.infer_lhs = infer_name  # won't work with a path wrapper

astroid/nodes/node_classes.py

@@ -30,7 +30,7 @@
 from astroid.nodes import _base_nodes
 from astroid.nodes.const import OP_PRECEDENCE
 from astroid.nodes.node_ng import NodeNG
-from astroid.typing import SuccessfulInferenceResult
+from astroid.typing import InferenceResult, SuccessfulInferenceResult
 
 if sys.version_info >= (3, 8):
     from typing import Literal
@@ -63,6 +63,10 @@ def _is_const(value):
     ],
     Any,
 ]
+InferLHS = Callable[
+    [_NodesT, Optional[InferenceContext]],
+    typing.Generator[InferenceResult, None, None],
+]
 
 
 @decorators.raise_if_nothing_inferred
@@ -329,7 +333,7 @@ class LookupMixIn(NodeNG):
     """Mixin to look up a name in the right scope."""
 
     @lru_cache()  # noqa
-    def lookup(self, name: str) -> tuple[str, list[NodeNG]]:
+    def lookup(self, name: str) -> tuple[LocalsDictNodeNG, list[NodeNG]]:
         """Lookup where the given variable is assigned.
 
         The lookup starts from self's scope. If self is not a frame itself
@@ -380,6 +384,8 @@ class AssignName(_base_nodes.NoChildrenNode, LookupMixIn, _base_nodes.ParentAssi
 
     _other_fields = ("name",)
 
+    infer_lhs: ClassVar[InferLHS[AssignName]]
+
     @decorators.deprecate_default_argument_values(name="str")
     def __init__(
         self,