diff --git a/packages/plugin-ext/src/plugin/types-impl.ts b/packages/plugin-ext/src/plugin/types-impl.ts
index d9243b531cb56..df8deb40f539d 100644
--- a/packages/plugin-ext/src/plugin/types-impl.ts
+++ b/packages/plugin-ext/src/plugin/types-impl.ts
@@ -423,7 +423,7 @@ export class Position {
         return false;
     }
 
-    toJSON(): unknown {
+    toJSON(): object {
         return { line: this.line, character: this.character };
     }
 }
@@ -556,7 +556,7 @@ export class Range {
             && Position.isPosition(range.end);
     }
 
-    toJSON(): unknown {
+    toJSON(): object[] {
         return [this.start, this.end];
     }
 }