type ComponentPublicInstance<C, Options> = {
  $options: Options & 'intersection anything'  // intersection here is critical
} & ExtractComputedReturns<C>   // this type intersection is important

type WhatEver<T> = T extends 1 ? true : false  

type MixinToOptionTypes<T> = T extends ComponentOptionsBase<
  infer C, 1, 1
>
  ? OptionTypesType<C>
  : never

type IntersectionMixin<T> = WhatEver<T> extends true  // a conditional is required here for reproduction
  ? OptionTypesType<{}>
  : MixinToOptionTypes<T>

type CreateComponentPublicInstance<
  Mixin extends 1 ,
  Extends extends 1,
> = ComponentPublicInstance<
  (IntersectionMixin<Mixin> & IntersectionMixin<Extends>)['C'],
  ComponentOptionsBase<{}, Mixin, Extends>
>

interface ComponentOptionsBase<
  _C extends ComputedOptions,
  Mixin extends 1,
  Extends extends 1,
>  {
  data?: (
    this: CreateComponentPublicInstance<
      Mixin,
      Extends
    >,
  ) => {}  // a function property is required, method syntax cannot reproduce.
}

type ComputedGetter = (...args: any[]) => any
type ComputedOptions = Record<
  string,
  ComputedGetter | {get: ComputedGetter }  // a union type for getter is required
>

type ExtractComputedReturns<T extends any> = {
  [key in keyof T]: T[key] extends { get: (...args: any[]) => infer TReturn }
    ? TReturn
    : T[key] extends (...args: any[]) => infer TReturn
    ? TReturn
    : never
}

type OptionTypesType<C = {}> = { C: C }

type Mixin = 1; type Extend = 1;

type A1 = ComponentOptionsBase<any,Mixin,Extend> &{sth?:never}
export type Test1 = A1 extends ComponentOptionsBase<any,any,any>?'yes':'no'
//   ^? expect Yes, got No in TS 5.1.0, but Yes in 4.9.5

// following types are for reference. They behave the same.
type A2 = ComponentOptionsBase<any,Mixin,Extend>
export type Test2 = A2 extends ComponentOptionsBase<any,any,any>?'yes':'no'
//   ^?  yes

type A3 = ComponentOptionsBase<any,Mixin,any> &{sth?:never}
export type Test3 = A3 extends ComponentOptionsBase<any,any,any>?'yes':'no'
//   ^? yes

type A4 = ComponentOptionsBase<any,any,Extend> &{sth?:never}
export type Test4 = A4 extends ComponentOptionsBase<any,any,any>?'yes':'no'
//   ^? yes