diff --git a/crates/toml_edit/src/document.rs b/crates/toml_edit/src/document.rs
index df8888c7..6217fbf6 100644
--- a/crates/toml_edit/src/document.rs
+++ b/crates/toml_edit/src/document.rs
@@ -25,6 +25,14 @@ impl<S: AsRef<str>> ImDocument<S> {
     pub fn parse(raw: S) -> Result<Self, crate::TomlError> {
         crate::parser::parse_document(raw)
     }
+
+    /// # Panics
+    ///
+    /// If run on on a `Document` not generated by the parser
+    pub(crate) fn despan(&mut self) {
+        self.root.despan(self.raw.as_ref());
+        self.trailing.despan(self.raw.as_ref());
+    }
 }
 
 impl<S> ImDocument<S> {
@@ -56,16 +64,17 @@ impl<S: AsRef<str>> ImDocument<S> {
     }
 }
 
-impl<S: Into<String>> ImDocument<S> {
+impl<S: AsRef<str>> ImDocument<S> {
     /// Allow editing of the [`Document`]
-    pub fn into_mut(self) -> Document {
-        let mut doc = Document {
+    pub fn into_mut(mut self) -> Document {
+        self.despan();
+        Document {
             root: self.root,
             trailing: self.trailing,
-            raw: Some(self.raw.into()),
-        };
-        doc.despan();
-        doc
+            // prevent a child of `ImDocument` from being inserted into `Document` and having the
+            // spans evaluated when using `crate::encode`
+            raw: None,
+        }
     }
 }
 
@@ -148,14 +157,6 @@ impl Document {
     pub fn trailing(&self) -> &RawString {
         &self.trailing
     }
-
-    /// # Panics
-    ///
-    /// If run on on a `Document` not generated by the parser
-    pub(crate) fn despan(&mut self) {
-        self.root.despan(self.raw.as_deref().unwrap());
-        self.trailing.despan(self.raw.as_deref().unwrap());
-    }
 }
 
 impl Default for Document {