fix: Overload cases

Author: taiyakihitotsu

source/internal/type.d.ts

@@ -198,13 +198,19 @@ type RecurseUniqueUnionDeep<U> =
 		: U extends UnknownArray
 			? InternalUniqueUnionDeep<U>
 			: U extends Lambda
-				// `Parametes` and `ReturnType` results are possible to be object or lambda; both should be passed into `UniqueUnionDeep`.
-				? (...args: UniqueUnionDeep<Parameters<U>> extends infer A extends any[] ? A : never) => (UniqueUnionDeep<ReturnType<U>>)
+				? IsNever<keyof U> extends true
+					// `Parametes` and `ReturnType` results are possible to be object or lambda; both should be passed into `UniqueUnionDeep`.
+					? HasMultipleCallSignatures<U> extends true
+						? U
+						: (...args: UniqueUnionDeep<Parameters<U>> extends infer A extends any[] ? A : never) => (UniqueUnionDeep<ReturnType<U>>)
+					: U
 				: U;
+
 /**
 Note: Wrapping this with `Simplify`, `test-d/exact.ts` fails in "Spec: recursive type with union".
 */
-type InternalUniqueUnionDeep<U extends object> = {[K in keyof U]: UniqueUnion<RecurseUniqueUnionDeep<U[K]>>};
+type InternalUniqueUnionDeep<U extends object> =
+	{[K in keyof U]: UniqueUnion<RecurseUniqueUnionDeep<U[K]>>};
 
 type Lambda = ((...args: any[]) => any);
 

test-d/is-equal.ts

@@ -63,6 +63,17 @@ expectType<true>({} as IsEqual<AnyLambda, AnyLambda>);
 expectType<false>({} as IsEqual<AnyLambda, NumberLambda>);
 expectType<false>({} as IsEqual<NumberLambda, AnyLambda>);
 
+// Branded Type
+expectType<false>({} as IsEqual<1 & {foo?: 1}, 1>);
+expectType<true>({} as IsEqual<1 & {foo?: 1}, 1 & {foo?: 1}>);
+expectType<false>({} as IsEqual<{bar: 'a'} & {foo?: 1}, {bar: 'a'}>);
+expectType<false>({} as IsEqual<((value: number) => void) & {foo?: 1}, (value: number) => void>);
+
+// Overload
+expectType<false>({} as IsEqual<{(value: 'a'): 1; (value: string): 1}, (value: string) => 1>);
+expectType<false>({} as IsEqual<{(value: 'a'): 1; (value: string): 1; key: 'value'}, (value: string) => 1>);
+expectType<false>({} as IsEqual<{(value: 'a'): 1; (value: string): 1; key: 'value'}, {(value: string): 1; key: 'value'}>);
+
 // Lambda: Identical Union and Intersection cases.
 expectType<true>({} as IsEqual<SpecificNumericLambda & SpecificNumericLambda, SpecificNumericLambda>); // eslint-disable-line @typescript-eslint/no-duplicate-type-constituents
 expectType<true>({} as IsEqual<SpecificNumericLambda | SpecificNumericLambda, SpecificNumericLambda>); // eslint-disable-line @typescript-eslint/no-duplicate-type-constituents