diff --git a/.github/generated/ast_changes_watch_list.yml b/.github/generated/ast_changes_watch_list.yml
index 6f7e577b0b832..4d1aa278c1e82 100644
--- a/.github/generated/ast_changes_watch_list.yml
+++ b/.github/generated/ast_changes_watch_list.yml
@@ -40,7 +40,7 @@ src:
   - 'crates/oxc_span/src/generated/assert_layouts.rs'
   - 'crates/oxc_span/src/generated/derive_dummy.rs'
   - 'crates/oxc_span/src/generated/derive_estree.rs'
-  - 'crates/oxc_span/src/source_type/mod.rs'
+  - 'crates/oxc_span/src/source_type.rs'
   - 'crates/oxc_span/src/span.rs'
   - 'crates/oxc_syntax/src/generated/assert_layouts.rs'
   - 'crates/oxc_syntax/src/generated/derive_clone_in.rs'
diff --git a/crates/oxc_span/src/source_type/mod.rs b/crates/oxc_span/src/source_type.rs
similarity index 96%
rename from crates/oxc_span/src/source_type/mod.rs
rename to crates/oxc_span/src/source_type.rs
index a9bca75b6e937..9963f0b02639c 100644
--- a/crates/oxc_span/src/source_type/mod.rs
+++ b/crates/oxc_span/src/source_type.rs
@@ -1,4 +1,10 @@
-use std::{hash::Hash, path::Path};
+use std::{
+    borrow::Cow,
+    error::Error,
+    fmt::{self, Display},
+    ops::Deref,
+    path::Path,
+};
 
 use oxc_allocator::{Allocator, CloneIn, Dummy};
 use oxc_ast_macros::ast;
@@ -6,9 +12,6 @@ use oxc_estree::ESTree;
 
 use crate::ContentEq;
 
-mod error;
-pub use error::UnknownExtension;
-
 /// Source Type for JavaScript vs TypeScript / Script vs Module / JSX
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -551,6 +554,33 @@ impl SourceType {
     }
 }
 
+/// Error returned by [`SourceType::from_path`] and [`SourceType::from_extension`] when
+/// the file extension is not found or recognized.
+#[derive(Debug)]
+pub struct UnknownExtension(Cow<'static, str>);
+
+impl UnknownExtension {
+    fn new<S: Into<Cow<'static, str>>>(ext: S) -> Self {
+        Self(ext.into())
+    }
+}
+
+impl Deref for UnknownExtension {
+    type Target = str;
+
+    fn deref(&self) -> &str {
+        &self.0
+    }
+}
+
+impl Display for UnknownExtension {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Unknown file extension: {}", self.0)
+    }
+}
+
+impl Error for UnknownExtension {}
+
 #[cfg(test)]
 mod tests {
     use super::SourceType;
diff --git a/crates/oxc_span/src/source_type/error.rs b/crates/oxc_span/src/source_type/error.rs
deleted file mode 100644
index 69aa693ce72d4..0000000000000
--- a/crates/oxc_span/src/source_type/error.rs
+++ /dev/null
@@ -1,30 +0,0 @@
-use std::{borrow::Cow, error::Error, fmt, ops::Deref};
-
-/// Error returned by [`SourceType::from_path`] when the file extension is not
-/// found or recognized.
-///
-/// [`SourceType::from_path`]: `crate::SourceType::from_path`
-#[derive(Debug)]
-pub struct UnknownExtension(/* msg */ pub(crate) Cow<'static, str>);
-
-impl Deref for UnknownExtension {
-    type Target = str;
-
-    fn deref(&self) -> &str {
-        &self.0
-    }
-}
-impl UnknownExtension {
-    #[inline]
-    pub(crate) fn new<S: Into<Cow<'static, str>>>(ext: S) -> Self {
-        Self(ext.into())
-    }
-}
-
-impl fmt::Display for UnknownExtension {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "Unknown file extension: {}", self.0)
-    }
-}
-
-impl Error for UnknownExtension {}
diff --git a/tasks/ast_tools/src/main.rs b/tasks/ast_tools/src/main.rs
index b7049bdb42143..fdc7aac611995 100644
--- a/tasks/ast_tools/src/main.rs
+++ b/tasks/ast_tools/src/main.rs
@@ -227,7 +227,7 @@ static SOURCE_PATHS: &[&str] = &[
     "crates/oxc_syntax/src/symbol.rs",
     "crates/oxc_syntax/src/reference.rs",
     "crates/oxc_span/src/span.rs",
-    "crates/oxc_span/src/source_type/mod.rs",
+    "crates/oxc_span/src/source_type.rs",
     "crates/oxc_regular_expression/src/ast.rs",
     "napi/parser/src/raw_transfer_types.rs",
 ];