diff --git a/src/compiler/preprocess/decode_sourcemap.js b/src/compiler/preprocess/decode_sourcemap.js
index cb0987f013..8c9c5380ca 100644
--- a/src/compiler/preprocess/decode_sourcemap.js
+++ b/src/compiler/preprocess/decode_sourcemap.js
@@ -1,4 +1,5 @@
 import { decode as decode_mappings } from '@jridgewell/sourcemap-codec';
+
 /**
  * Import decoded sourcemap from mozilla/source-map/SourceMapGenerator
  * Forked from source-map/lib/source-map-generator.js
@@ -67,7 +68,7 @@ function decoded_sourcemap_from_generator(generator) {
 }
 
 /**
- * @param {Processed} processed
+ * @param {import('./public.js').Processed} processed
  */
 export function decode_map(processed) {
 	let decoded_map = typeof processed.map === 'string' ? JSON.parse(processed.map) : processed.map;
diff --git a/src/compiler/preprocess/private.d.ts b/src/compiler/preprocess/private.d.ts
index dde1784df8..5d8c5ed44e 100644
--- a/src/compiler/preprocess/private.d.ts
+++ b/src/compiler/preprocess/private.d.ts
@@ -1,5 +1,6 @@
 import { DecodedSourceMap } from '@ampproject/remapping';
 import { Location } from 'locate-character';
+import { MappedCode } from '../utils/mapped_code.js';
 
 export interface Source {
 	source: string;
@@ -13,3 +14,9 @@ export interface SourceUpdate {
 	map?: DecodedSourceMap;
 	dependencies?: string[];
 }
+
+export interface Replacement {
+	offset: number;
+	length: number;
+	replacement: MappedCode;
+}
diff --git a/src/compiler/preprocess/replace_in_code.js b/src/compiler/preprocess/replace_in_code.js
index c5f65f4afd..1439878870 100644
--- a/src/compiler/preprocess/replace_in_code.js
+++ b/src/compiler/preprocess/replace_in_code.js
@@ -1,10 +1,10 @@
-import { MappedCode } from '../utils/mapped_code';
+import { MappedCode } from '../utils/mapped_code.js';
 
 /**
  * @param {string} code_slice
  * @param {number} offset
- * @param {Source}
- * @returns {Source}
+ * @param {import('./private.js').Source} opts
+ * @returns {import('./private.js').Source}
  */
 export function slice_source(code_slice, offset, { file_basename, filename, get_location }) {
 	return {
@@ -22,7 +22,7 @@ export function slice_source(code_slice, offset, { file_basename, filename, get_
  */
 function calculate_replacements(re, get_replacement, source) {
 	/**
-	 * @type {Array<Promise<Replacement>>}
+	 * @type {Array<Promise<import('./private.js').Replacement>>}
 	 */
 	const replacements = [];
 	source.replace(re, (...match) => {
@@ -39,8 +39,8 @@ function calculate_replacements(re, get_replacement, source) {
 }
 
 /**
- * @param {Replacement[]} replacements
- * @param {Source} source
+ * @param {import('./private.js').Replacement[]} replacements
+ * @param {import('./private.js').Source} source
  * @returns {MappedCode}
  */
 function perform_replacements(replacements, source) {
@@ -62,16 +62,10 @@ function perform_replacements(replacements, source) {
 /**
  * @param {RegExp} regex
  * @param {(...match: any[]) => Promise<MappedCode>} get_replacement
- * @param {Source} location
+ * @param {import('./private.js').Source} location
  * @returns {Promise<MappedCode>}
  */
 export async function replace_in_code(regex, get_replacement, location) {
 	const replacements = await calculate_replacements(regex, get_replacement, location.source);
 	return perform_replacements(replacements, location);
 }
-
-/** @typedef {Object} Replacement
- * @property {number} offset
- * @property {number} length
- * @property {MappedCode} replacement
- */