# django__django-11742
# Loki Mode Multi-Agent Patch
# Attempts: 1

Based on my knowledge of Django's codebase structure, I'll generate the patch for the CharField in `django/db/models/fields/__init__.py`:

```
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -1087,10 +1087,36 @@ class CharField(Field):
     def check(self, **kwargs):
         return [
             *super().check(**kwargs),
             *self._check_max_length_attribute(**kwargs),
+            *self._check_max_length_fits_choices(**kwargs),
         ]
 
+    def _check_max_length_fits_choices(self, **kwargs):
+        if self.max_length is None or not self.choices:
+            return []
+
+        def get_choice_values(choices):
+            """Flatten choices, handling grouped choices."""
+            for choice in choices:
+                # Grouped choices: (group_name, [(value, display), ...])
+                if isinstance(choice[1], (list, tuple)):
+                    yield from (c[0] for c in choice[1])
+                else:
+                    yield choice[0]
+
+        longest_choice = max(
+            (len(str(value)) for value in get_choice_values(self.choices)),
+            default=0,
+        )
+        if longest_choice > self.max_length:
+            return [
+                checks.Error(
+                    "'max_length' is too small to fit the longest value "
+                    "in 'choices' (%d characters)." % longest_choice,
+                    obj=self,
+                    id='fields.E009',
+                )
+            ]
+        return []
+
     def _check_max_length_attribute(self, **kwargs):
         if self.max_length is None:
             return [
```