Element implicitly has an 'any' type because expression of type 'string' can't be used to index type

[FreeSlave]

Bug Report

The following code used to work on 4.2.3, but does not build with 4.3.2, reporting the error on the last line

type ObjectFixedKeys<T extends object> = {
    [K in keyof T]: string extends K ? never : K
} extends { [_ in keyof T]: infer U }
    ? U
    : never

type DistributeKeysUnion<U> = U extends string
    ? { [K in U]: any }
    : never

type ObjectDictionaryKeys<T extends object> = Exclude<
    T,
    DistributeKeysUnion<ObjectFixedKeys<T>>
    >

type Condition = { $and: Array<Condition> }
    | { $or: Array<Condition> }
    | { [member: string]: string }

type O = ObjectFixedKeys<Condition>
type D = DistributeKeysUnion<ObjectFixedKeys<Condition>>

declare const s: string
type CT = ObjectDictionaryKeys<Condition>
declare const ct : CT
const h = ct[s]

Error:

Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CT'.
  No index signature with a parameter of type 'string' was found on type 'CT'.

🕗 Version & Regression Information

I tracked the regression to the version 4.3.0-dev.20210422

Probably related to 8ea4ec9

⏯ Playground Link

Playground link with relevant code

Note how the last line is evaluated to never, however if you select version 4.2.3 it gets evaluated to "foo" | "bar" as expected.

[weswigham]

Related: #44143 ? Looks like the same type at the core, anyway.