diff --git a/apps/oxlint/conformance/src/rule_tester.ts b/apps/oxlint/conformance/src/rule_tester.ts
index e7e32d133944c..43f744718fd31 100644
--- a/apps/oxlint/conformance/src/rule_tester.ts
+++ b/apps/oxlint/conformance/src/rule_tester.ts
@@ -104,7 +104,8 @@ function addBeforeHook<T extends TestCase>(test: T): T {
   const clonedTest = { ...test };
 
   if (Object.hasOwn(test, "before")) {
-    const originalBefore = test.before;
+    // oxlint-disable-next-line typescript/unbound-method - called with `.call`
+    const originalBefore = test.before as () => void;
     test.before = function (this) {
       setCurrentTest(clonedTest);
       originalBefore!.call(this);
diff --git a/apps/oxlint/src-js/cli.ts b/apps/oxlint/src-js/cli.ts
index 6474b56057d25..57765bf4ebf83 100644
--- a/apps/oxlint/src-js/cli.ts
+++ b/apps/oxlint/src-js/cli.ts
@@ -25,19 +25,19 @@ let loadJsConfigs: typeof import("./js_config.ts").loadJsConfigs | null = null;
  */
 function loadPluginWrapper(
   path: string,
-  pluginName: string | null,
+  pluginName: string | null | undefined,
   pluginNameIsAlias: boolean,
-  workspaceUri: string | null,
+  workspaceUri: string | null | undefined,
 ): Promise<string> {
   if (loadPlugin === null) {
     // Use promises here instead of making `loadPluginWrapper` an async function,
     // to avoid a micro-tick and extra wrapper `Promise` in all later calls to `loadPluginWrapper`
     return import("./plugins/index.ts").then((mod) => {
       ({ loadPlugin, lintFile, setupRuleConfigs } = mod);
-      return loadPlugin(path, pluginName, pluginNameIsAlias, workspaceUri);
+      return loadPlugin(path, pluginName ?? null, pluginNameIsAlias, workspaceUri ?? null);
     });
   }
-  return loadPlugin(path, pluginName, pluginNameIsAlias, workspaceUri);
+  return loadPlugin(path, pluginName ?? null, pluginNameIsAlias, workspaceUri ?? null);
 }
 
 /**
@@ -71,12 +71,12 @@ function setupRuleConfigsWrapper(optionsJSON: string): string | null {
 function lintFileWrapper(
   filePath: string,
   bufferId: number,
-  buffer: Uint8Array | null,
+  buffer: Uint8Array | null | undefined,
   ruleIds: number[],
   optionsIds: number[],
   settingsJSON: string,
   globalsJSON: string,
-  workspaceUri: string | null,
+  workspaceUri: string | null | undefined,
 ): string | null {
   // `lintFileWrapper` is never called without `loadPluginWrapper` being called first,
   // so `lintFile` must be defined here
@@ -84,12 +84,12 @@ function lintFileWrapper(
   return lintFile(
     filePath,
     bufferId,
-    buffer,
+    buffer ?? null,
     ruleIds,
     optionsIds,
     settingsJSON,
     globalsJSON,
-    workspaceUri,
+    workspaceUri ?? null,
   );
 }
 
diff --git a/apps/oxlint/src-js/generated/deserialize.d.ts b/apps/oxlint/src-js/generated/deserialize.d.ts
index d2815decb03cd..7473511fa3e1a 100644
--- a/apps/oxlint/src-js/generated/deserialize.d.ts
+++ b/apps/oxlint/src-js/generated/deserialize.d.ts
@@ -2,10 +2,11 @@
 // To edit this generated file you have to edit `tasks/ast_tools/src/generators/raw_transfer.rs`.
 
 import type { Program } from "./types.d.ts";
+import type { Node, Comment } from "../plugins/types.ts";
 import type { Location as SourceLocation } from "../plugins/location.ts";
 
 type BufferWithArrays = Uint8Array & { uint32: Uint32Array; float64: Float64Array };
-type GetLoc = (node: { range: [number, number] }) => SourceLocation;
+type GetLoc = (node: Node | Comment) => SourceLocation;
 
 export declare function deserializeProgramOnly(
   buffer: BufferWithArrays,
diff --git a/apps/oxlint/src-js/package/rule_tester.ts b/apps/oxlint/src-js/package/rule_tester.ts
index f1fe135e314b6..f86c03c783473 100644
--- a/apps/oxlint/src-js/package/rule_tester.ts
+++ b/apps/oxlint/src-js/package/rule_tester.ts
@@ -41,7 +41,7 @@ type ItFn = ((text: string, fn: () => void) => void) & { only?: ItFn };
  * @param method - Test case logic
  * @returns Returned value of `method`
  */
-function defaultDescribe<R>(text: string, method: () => R): R {
+function defaultDescribe<T, R>(this: T, text: string, method: (this: T) => R): R {
   return method.call(this);
 }
 
@@ -58,7 +58,7 @@ let describe: DescribeFn =
  * @throws {Error} Any error upon execution of `method`
  * @returns Returned value of `method`
  */
-function defaultIt<R>(text: string, method: () => R): R {
+function defaultIt<T, R>(this: T, text: string, method: (this: T) => R): R {
   try {
     return method.call(this);
   } catch (err) {
@@ -320,8 +320,8 @@ interface TestCase extends Config {
   filename?: string;
   options?: Options;
   settings?: Settings;
-  before?: (this: this) => void;
-  after?: (this: this) => void;
+  before?(this: this): void;
+  after?(this: this): void;
 }
 
 /**
@@ -1566,6 +1566,7 @@ function getTestName(test: TestCase): string {
  * @throws {*} - Value thrown by the hook function
  */
 function runBeforeHook(test: TestCase): void {
+  // oxlint-disable-next-line typescript/unbound-method - bound in `runHook`
   if (Object.hasOwn(test, "before")) runHook(test, test.before, "before");
 }
 
@@ -1576,6 +1577,7 @@ function runBeforeHook(test: TestCase): void {
  * @throws {*} - Value thrown by the hook function
  */
 function runAfterHook(test: TestCase): void {
+  // oxlint-disable-next-line typescript/unbound-method - bound in `runHook`
   if (Object.hasOwn(test, "after")) runHook(test, test.after, "after");
 }
 
diff --git a/apps/oxlint/src-js/plugins/cfg.ts b/apps/oxlint/src-js/plugins/cfg.ts
index cabc979a8d30c..6ecbe7c1c643d 100644
--- a/apps/oxlint/src-js/plugins/cfg.ts
+++ b/apps/oxlint/src-js/plugins/cfg.ts
@@ -17,7 +17,7 @@ import {
 import { ancestors } from "../generated/walk.js";
 import { debugAssert, debugAssertIsFunction } from "../utils/asserts.ts";
 
-import type { EnterExit } from "./visitor.ts";
+import type { CfgVisitFn, EnterExit } from "./visitor.ts";
 import type { Node, Program } from "../generated/types.d.ts";
 import type { CompiledVisitors } from "../generated/walk.js";
 
@@ -139,10 +139,10 @@ export function walkProgramWithCfg(ast: Program, visitors: CompiledVisitors): vo
       // Call method (CFG event). `typeId` is event type ID.
       debugAssert(Array.isArray(stepData[i]), "`stepData` should contain an array for CFG events");
 
-      const visit = visitors[typeId];
+      const visit = visitors[typeId] as CfgVisitFn;
       if (visit !== null) {
         debugAssertIsFunction(visit);
-        visit.apply(undefined, stepData[i]);
+        visit.apply(undefined, stepData[i] as unknown[]);
       }
     }
   }
diff --git a/apps/oxlint/src-js/plugins/visitor.ts b/apps/oxlint/src-js/plugins/visitor.ts
index 667ef069b861f..003356eb947e1 100644
--- a/apps/oxlint/src-js/plugins/visitor.ts
+++ b/apps/oxlint/src-js/plugins/visitor.ts
@@ -98,7 +98,7 @@ import type { Node, Visitor } from "./types.ts";
 export type VisitFn = (node: Node) => void;
 
 // Visit function for a specific CFG event.
-type CfgVisitFn = (...args: unknown[]) => void;
+export type CfgVisitFn = (...args: unknown[]) => void;
 
 // Enter+exit pair, for non-leaf nodes in compiled visitor.
 export interface EnterExit {
@@ -268,7 +268,7 @@ export function addVisitorToCompiled(visitor: Visitor): void {
   for (let i = 0; i < keysLen; i++) {
     let name = keys[i];
 
-    const visitFn = visitor[name];
+    const visitFn = visitor[name] as VisitFn;
     if (typeof visitFn !== "function") {
       throw new TypeError(`'${name}' property of visitor object is not a function`);
     }
@@ -649,7 +649,7 @@ function mergeCfgVisitFns(visitProps: VisitProp[]): CfgVisitFn {
   if (numVisitFns === 1) {
     // Only 1 visit function, so no need to merge
     debugAssertIsNonNull(visitProps[0].fn);
-    mergedFn = visitProps[0].fn;
+    mergedFn = visitProps[0].fn as CfgVisitFn;
   } else {
     // No need to sort in order of specificity, because each rule can only have 1 handler for each CFG event
 
@@ -675,7 +675,7 @@ function mergeCfgVisitFns(visitProps: VisitProp[]): CfgVisitFn {
       debugAssertIsNonNull(visitProps[i].fn);
       visitFns.push(visitProps[i].fn!);
     }
-    mergedFn = merger(...visitFns);
+    mergedFn = merger(...(visitFns as CfgVisitFn[]));
 
     visitFns.length = 0;
   }
diff --git a/apps/oxlint/test/tokens.type_test.ts b/apps/oxlint/test/tokens.type_test.ts
index 0a988d3fd03e8..07d491f8af928 100644
--- a/apps/oxlint/test/tokens.type_test.ts
+++ b/apps/oxlint/test/tokens.type_test.ts
@@ -125,7 +125,7 @@ declare const node: Node;
 
 // Options with `filter` only -> `Token[]`
 {
-  const opts = { filter: (token: Token) => token.type === "Keyword" };
+  const opts = { filter: (token: TokenOrComment) => token.type === "Keyword" };
   const result = getTokens(node, opts);
   true satisfies IsExact<typeof result, Token[]>;
 }
@@ -277,7 +277,7 @@ declare const node: Node;
 
 // Options with `filter` only -> `Token | null`
 {
-  const opts = { filter: (token: Token) => token.type === "Keyword" };
+  const opts = { filter: (token: TokenOrComment) => token.type === "Keyword" };
   const result = getFirstToken(node, opts);
   true satisfies IsExact<typeof result, Token | null>;
 }
diff --git a/apps/oxlint/tsconfig.json b/apps/oxlint/tsconfig.json
index eebc3169ba29f..295145f4b589c 100644
--- a/apps/oxlint/tsconfig.json
+++ b/apps/oxlint/tsconfig.json
@@ -6,12 +6,9 @@
     "noEmit": true,
     "target": "ESNext",
     "allowImportingTsExtensions": true,
-    "strict": false,
-    "noImplicitAny": true,
-    "strictNullChecks": true,
+    "strict": true,
     "skipLibCheck": true,
-    "noUnusedLocals": true,
-    "useUnknownInCatchVariables": true
+    "noUnusedLocals": true
   },
   "exclude": ["node_modules", "fixtures", "test/fixtures/*/files", "conformance/submodules"]
 }
diff --git a/tasks/ast_tools/src/generators/raw_transfer.rs b/tasks/ast_tools/src/generators/raw_transfer.rs
index 460d826f98cc2..8b05b90f74d0e 100644
--- a/tasks/ast_tools/src/generators/raw_transfer.rs
+++ b/tasks/ast_tools/src/generators/raw_transfer.rs
@@ -208,10 +208,11 @@ fn generate_deserializers(
     #[rustfmt::skip]
     let code_type_definition_linter = "
         import type { Program } from './types.d.ts';
+        import type { Node, Comment } from '../plugins/types.ts';
         import type { Location as SourceLocation } from '../plugins/location.ts';
 
         type BufferWithArrays = Uint8Array & { uint32: Uint32Array; float64: Float64Array };
-        type GetLoc = (node: { range: [number, number] }) => SourceLocation;
+        type GetLoc = (node: Node | Comment) => SourceLocation;
 
         export declare function deserializeProgramOnly(
             buffer: BufferWithArrays,