diff --git a/src/language/ast.d.ts b/src/language/ast.d.ts
index 61cb9f4eb5..07c1af4f73 100644
--- a/src/language/ast.d.ts
+++ b/src/language/ast.d.ts
@@ -33,7 +33,7 @@ export class Location {
 
   constructor(startToken: Token, endToken: Token, source: Source);
 
-  toJSON(): { start: number; end: number };
+  toJSON(): { start: number; end: number; source: Source };
 }
 
 /**
diff --git a/src/language/ast.js b/src/language/ast.js
index 0b69454977..a00374201b 100644
--- a/src/language/ast.js
+++ b/src/language/ast.js
@@ -41,8 +41,8 @@ export class Location {
     this.source = source;
   }
 
-  toJSON(): {| start: number, end: number |} {
-    return { start: this.start, end: this.end };
+  toJSON(): {| start: number, end: number, source: Source |} {
+    return { start: this.start, end: this.end, source: this.source };
   }
 }
 
diff --git a/src/language/source.js b/src/language/source.js
index 05a0fc9c81..cd16c10af2 100644
--- a/src/language/source.js
+++ b/src/language/source.js
@@ -48,6 +48,13 @@ export class Source {
   get [SYMBOL_TO_STRING_TAG]() {
     return 'Source';
   }
+
+  toJSON(): {| body: string, name: string |} {
+    return {
+      body: this.body,
+      name: this.name,
+    };
+  }
 }
 
 /**