diff --git a/index.js b/index.js
index ce2e5ac..278d0c4 100644
--- a/index.js
+++ b/index.js
@@ -11,6 +11,7 @@ class SourceFile {
 	constructor(path, resolvedPath) {
 		this.path = path;
 		this.resolvedPath = resolvedPath;
+		Object.freeze(this);
 	}
 
 	get name() {