Fix unhashable-member crash when lambda used as a dict key (#7454)

Author: jacobtylerwalls

doc/whatsnew/fragments/7453.bugfix

@@ -0,0 +1,3 @@
+Fixed a crash in the ``unhashable-member`` checker when using a ``lambda`` as a dict key.
+
+Closes #7453

pylint/checkers/utils.py

@@ -1942,6 +1942,8 @@ def is_hashable(node: nodes.NodeNG) -> bool:
         for inferred in node.infer():
             if inferred is astroid.Uninferable:
                 return True
+            if not hasattr(inferred, "igetattr"):
+                return True
             hash_fn = next(inferred.igetattr("__hash__"))
             if hash_fn.parent is inferred:
                 return True

tests/functional/u/unhashable_member.py

@@ -21,3 +21,4 @@ class Unhashable:
 {[1, 2, 3]}  # [unhashable-member]
 {"tomato": "tomahto"}
 {dict: {}}
+{lambda x: x: "tomato"}  # pylint: disable=unnecessary-lambda