diff --git a/packages/babel-core/src/config/config-chain.ts b/packages/babel-core/src/config/config-chain.ts
index 83853974f597..7867e039e433 100644
--- a/packages/babel-core/src/config/config-chain.ts
+++ b/packages/babel-core/src/config/config-chain.ts
@@ -54,7 +54,7 @@ export type PresetInstance = {
 };
 
 export type ConfigContext = {
-  filename: string | void;
+  filename: string | undefined;
   cwd: string;
   root: string;
   envName: string;
@@ -899,7 +899,7 @@ function matchesPatterns(
 function matchPattern(
   pattern: IgnoreItem,
   dirname: string,
-  pathToTest: unknown,
+  pathToTest: string | undefined,
   context: ConfigContext,
   configName?: string,
 ): boolean {
diff --git a/packages/babel-core/src/config/validation/option-assertions.ts b/packages/babel-core/src/config/validation/option-assertions.ts
index d233a02c3018..041e0c8cf0f5 100644
--- a/packages/babel-core/src/config/validation/option-assertions.ts
+++ b/packages/babel-core/src/config/validation/option-assertions.ts
@@ -256,7 +256,7 @@ function assertIgnoreItem(loc: GeneralPath, value: unknown): IgnoreItem {
       )} must be an array of string/Function/RegExp values, or undefined`,
     );
   }
-  return value;
+  return value as IgnoreItem;
 }
 
 export function assertConfigApplicableTest(
@@ -278,7 +278,7 @@ export function assertConfigApplicableTest(
       `${msg(loc)} must be a string/Function/RegExp, or an array of those`,
     );
   }
-  return value;
+  return value as ConfigApplicableTest;
 }
 
 function checkValidTest(value: unknown): value is string | Function | RegExp {
@@ -327,7 +327,7 @@ export function assertBabelrcSearch(
         `or an array of those, got ${JSON.stringify(value as any)}`,
     );
   }
-  return value;
+  return value as BabelrcSearch;
 }
 
 export function assertPluginList(
diff --git a/packages/babel-core/src/config/validation/options.ts b/packages/babel-core/src/config/validation/options.ts
index cd62d884f725..0d96c0b15d20 100644
--- a/packages/babel-core/src/config/validation/options.ts
+++ b/packages/babel-core/src/config/validation/options.ts
@@ -201,7 +201,13 @@ export type CallerMetadata = {
 export type EnvSet<T> = {
   [x: string]: T;
 };
-export type IgnoreItem = string | Function | RegExp;
+export type IgnoreItem =
+  | string
+  | RegExp
+  | ((
+      path: string | undefined,
+      context: { dirname: string; caller: CallerMetadata; envName: string },
+    ) => unknown);
 export type IgnoreList = ReadonlyArray<IgnoreItem>;
 
 export type PluginOptions = object | void | false;
diff --git a/packages/babel-core/src/errors/rewrite-stack-trace.ts b/packages/babel-core/src/errors/rewrite-stack-trace.ts
index 9c8a30ae30b0..1b463077b627 100644
--- a/packages/babel-core/src/errors/rewrite-stack-trace.ts
+++ b/packages/babel-core/src/errors/rewrite-stack-trace.ts
@@ -94,26 +94,30 @@ export function expectedError(error: Error) {
   return error;
 }
 
-export function beginHiddenCallStack<Fn extends Function>(fn: Fn): Fn {
+export function beginHiddenCallStack<A extends unknown[], R>(
+  fn: (...args: A) => R,
+) {
   if (!SUPPORTED) return fn;
 
   return Object.defineProperty(
-    function (this: any) {
+    function (...args: A) {
       setupPrepareStackTrace();
-      return fn.apply(this, arguments);
-    } as any as Fn,
+      return fn(...args);
+    },
     "name",
     { value: STOP_HIDNG },
   );
 }
 
-export function endHiddenCallStack<Fn extends Function>(fn: Fn): Fn {
+export function endHiddenCallStack<A extends unknown[], R>(
+  fn: (...args: A) => R,
+) {
   if (!SUPPORTED) return fn;
 
   return Object.defineProperty(
-    function (this: any) {
-      return fn.apply(this, arguments);
-    } as any as Fn,
+    function (...args: A) {
+      return fn(...args);
+    },
     "name",
     { value: START_HIDNG },
   );