Generic type param not narrowed in true branch of conditional type

TypeScript Version: 4.1.2

Search Terms: conditional type true branch generic narrowing

Code

type Num = 0 | 1 | 2
type Chr = 'a' | 'b' | 'c'

type Unit = Num | Chr

type NumCommand = 'add' | 'invert'
type ChrCommand = 'concat' | 'toLower'

type Command<U extends Unit> =
  U extends Num ? NumCommand :
  U extends Chr ? ChrCommand :
  never

type NumCommandData<C extends NumCommand> =
  C extends 'add' ? { otherNum: Num } :
  never

type ChrCommandData<C extends ChrCommand> =
  C extends 'concat' ? { otherChr: Chr } :
  never

type CommandData<U extends Unit, C extends Command<U>> =
  U extends Num ? NumCommandData<C> :
  U extends Chr ? ChrCommandData<C> :
  never

Expected behavior: in CommandData we are narrowing the generic parameter U using a conditional type, so in the true branch of the conditional C should also be "narrowed" (not sure if that's the correct term in this case) to the specific command type that depends on U.

Actual behavior: the compiler says that in the true branches of CommandData conditionals, C does not satisfy the constraint of either NumCommandData or ChrCommandData

Playground Link: playground

Related Issues: maybe #24085 ?