diff --git a/.basedpyright/baseline.json b/.basedpyright/baseline.json
index cce482d..e63d7cd 100644
--- a/.basedpyright/baseline.json
+++ b/.basedpyright/baseline.json
@@ -6389,6 +6389,14 @@
                     "lineCount": 1
                 }
             },
+            {
+                "code": "reportUnannotatedClassAttribute",
+                "range": {
+                    "startColumn": 4,
+                    "endColumn": 11,
+                    "lineCount": 1
+                }
+            },
             {
                 "code": "reportUnannotatedClassAttribute",
                 "range": {
diff --git a/pymbolic/mapper/__init__.py b/pymbolic/mapper/__init__.py
index ea1dce6..d2fdbfe 100644
--- a/pymbolic/mapper/__init__.py
+++ b/pymbolic/mapper/__init__.py
@@ -1673,6 +1673,7 @@ def map_constant(self, expr: object, /,
     map_remainder = map_constant
     map_power = map_constant
     map_matmul = map_constant
+    map_nan = map_constant
 
     map_left_shift = map_constant
     map_right_shift = map_constant