diff --git a/lighthouse-core/gather/driver.js b/lighthouse-core/gather/driver.js
index 20b01c4ce120..7a838f517a3a 100644
--- a/lighthouse-core/gather/driver.js
+++ b/lighthouse-core/gather/driver.js
@@ -59,6 +59,9 @@ const DEFAULT_PROTOCOL_TIMEOUT = 30000;
  * @typedef {LH.Protocol.StrictEventEmitter<LH.CrdpEvents>} CrdpEventEmitter
  */
 
+/**
+ * @implements {LH.Gatherer.FRTransitionalDriver}
+ */
 class Driver {
   /**
    * @param {Connection} connection
@@ -115,9 +118,6 @@ class Driver {
     this.fetcher = new Fetcher(this);
 
     this._runtimeController = new RuntimeController(this);
-
-    /** @type {LH.Gatherer.FRTransitionalDriver} */
-    const typecheck = this; // eslint-disable-line no-unused-vars
   }
 
   static get traceCategories() {
diff --git a/tsconfig.json b/tsconfig.json
index cf9e992357e1..b9d6cbc114fc 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -32,8 +32,6 @@
     // Opt-in to typechecking for some core tests.
     "lighthouse-core/test/scripts/lantern/constants-test.js",
     "lighthouse-core/test/fraggle-rock/gather/runtime-controller-test.js",
-    "lighthouse-core/test/fraggle-rock/gather/session-test.js",
-    "lighthouse-core/test/fraggle-rock/gather/driver-test.js",
     "lighthouse-core/test/gather/driver-test.js",
     "lighthouse-core/test/gather/gather-runner-test.js",
     "lighthouse-core/test/audits/script-treemap-data-test.js"
diff --git a/types/gatherer.d.ts b/types/gatherer.d.ts
index 394410d80fb8..cca056825c8d 100644
--- a/types/gatherer.d.ts
+++ b/types/gatherer.d.ts
@@ -13,22 +13,22 @@ declare global {
   module LH.Gatherer {
     /** The Lighthouse wrapper around a raw CDP session. */
     export interface FRProtocolSession {
-      hasNextProtocolTimeout(): boolean
-      getNextProtocolTimeout(): number
-      setNextProtocolTimeout(ms: number): void
-      on<TEvent extends keyof LH.CrdpEvents>(event: TEvent, callback: (...args: LH.CrdpEvents[TEvent]) => void): void
-      off<TEvent extends keyof LH.CrdpEvents>(event: TEvent, callback: (...args: LH.CrdpEvents[TEvent]) => void): void
-      sendCommand<TMethod extends keyof LH.CrdpCommands>(method: TMethod, ...params: LH.CrdpCommands[TMethod]['paramsType']): Promise<LH.CrdpCommands[TMethod]['returnType']>
+      hasNextProtocolTimeout(): boolean;
+      getNextProtocolTimeout(): number;
+      setNextProtocolTimeout(ms: number): void;
+      on<TEvent extends keyof LH.CrdpEvents>(event: TEvent, callback: (...args: LH.CrdpEvents[TEvent]) => void): void;
+      off<TEvent extends keyof LH.CrdpEvents>(event: TEvent, callback: (...args: LH.CrdpEvents[TEvent]) => void): void;
+      sendCommand<TMethod extends keyof LH.CrdpCommands>(method: TMethod, ...params: LH.CrdpCommands[TMethod]['paramsType']): Promise<LH.CrdpCommands[TMethod]['returnType']>;
     }
 
     /** The limited driver interface shared between pre and post Fraggle Rock Lighthouse. */
     export interface FRTransitionalDriver extends FRProtocolSession {
-      evaluateAsync(expression: string, options?: {useIsolation?: boolean}): Promise<any>
+      evaluateAsync(expression: string, options?: {useIsolation?: boolean}): Promise<any>;
     }
 
     /** The limited context interface shared between pre and post Fraggle Rock Lighthouse. */
     export interface FRTransitionalContext {
-      driver: FRTransitionalDriver
+      driver: FRTransitionalDriver;
     }
 
     export interface PassContext {