@@ -55,7 +55,7 @@ pub enum KeyValueOptionsDelimiter {
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+#[cfg_attr(feature = "visitor", derive(Visit))]
 /// A single key-value option.
 pub struct KeyValueOption {
     /// The name of the option.
@@ -64,6 +64,17 @@ pub struct KeyValueOption {
     pub option_value: KeyValueOptionKind,
 }
 
+#[cfg(feature = "visitor")]
+impl crate::ast::VisitMut for KeyValueOption {
+    fn visit_dyn(
+        &mut self,
+        visitor: &mut dyn crate::ast::VisitorMut<Break = ()>,
+    ) -> core::ops::ControlFlow<()> {
+        visitor.post_visit_option_name(&mut self.option_name)?;
+        self.option_value.visit_dyn(visitor)
+    }
+}
+
 /// An option can have a single value, multiple values or a nested list of values.
 ///
 /// A value can be numeric, boolean, etc. Enum-style values are represented
 
@@ -144,6 +144,11 @@ impl<V: Visitor> Visitor for Erased<'_, V, V::Break> {
 impl<V: VisitorMut> VisitorMut for Erased<'_, V, V::Break> {
     type Break = ();
 
+    fn post_visit_option_name(&mut self, name: &mut String) -> ControlFlow<()> {
+        let flow = self.inner.post_visit_option_name(name);
+        self.stash(flow)
+    }
+
     forward_hooks!(
         pre_visit_object_name post_visit_object_name: &mut ObjectName;
         pre_visit_query post_visit_query: &mut Query;
@@ -154,6 +159,7 @@ impl<V: VisitorMut> VisitorMut for Erased<'_, V, V::Break> {
         pre_visit_statement post_visit_statement: &mut Statement;
         pre_visit_value post_visit_value: &mut ValueWithSpan;
         pre_visit_ident post_visit_ident: &mut Ident;
+        pre_visit_string post_visit_string: &mut String;
     );
 }
 
@@ -220,7 +226,20 @@ macro_rules! visit_noop {
     };
 }
 
-visit_noop!(u8, u16, u32, u64, i8, i16, i32, i64, char, bool, String);
+visit_noop!(u8, u16, u32, u64, i8, i16, i32, i64, char, bool);
+
+impl Visit for String {
+    fn visit_dyn(&self, _visitor: &mut dyn Visitor<Break = ()>) -> ControlFlow<()> {
+        ControlFlow::Continue(())
+    }
+}
+
+impl VisitMut for String {
+    fn visit_dyn(&mut self, visitor: &mut dyn VisitorMut<Break = ()>) -> ControlFlow<()> {
+        visitor.pre_visit_string(self)?;
+        visitor.post_visit_string(self)
+    }
+}
 
 #[cfg(feature = "bigdecimal")]
 visit_noop!(bigdecimal::BigDecimal);
@@ -532,6 +551,21 @@ pub trait VisitorMut {
     fn post_visit_ident(&mut self, _ident: &mut Ident) -> ControlFlow<Self::Break> {
         ControlFlow::Continue(())
     }
+
+    /// Invoked before visiting a plain string field in the AST.
+    fn pre_visit_string(&mut self, _string: &mut String) -> ControlFlow<Self::Break> {
+        ControlFlow::Continue(())
+    }
+
+    /// Invoked after visiting a plain string field in the AST.
+    fn post_visit_string(&mut self, _string: &mut String) -> ControlFlow<Self::Break> {
+        ControlFlow::Continue(())
+    }
+
+    /// Invoked for the structural name of a key-value option.
+    fn post_visit_option_name(&mut self, _name: &mut String) -> ControlFlow<Self::Break> {
+        ControlFlow::Continue(())
+    }
 }
 
 struct RelationVisitor<F>(F);