Infer type in conditional cannot unify generics

TypeScript Version: 2.8.0-dev.20180315

Search Terms:
infer conditional unify generic function

Code

type Apply1<T, V> = T extends (item: V) => infer R ? R : never;
type A1 = Apply1< (item: string) => string[] , string>;
type B1 = Apply1< <U>(item: U) => U[], string>;

type Apply2<T, V> = T extends (item: V, obj: infer R) => any ? R : never;
type A2 = Apply2< (item: string, obj: string[]) => any , string>;
type B2 = Apply2< <U>(item: U, obj: U[]) => any , string>;

type Apply3<T, V> = T extends (item: V, obj: infer R) => infer R ? R : never;
type A3 = Apply3< (item: string, obj: string[]) => string[] , string>;
type B3 = Apply3< <U>(item: U, obj: U[]) => U[] , string>;

{
	"compilerOptions": {
		"allowJs": true,
		"target": "es6",
		"module": "commonjs",
		"outDir": "dest",
		"strictNullChecks": true,
		"jsx": "preserve",
		"strictFunctionTypes": true
	}
}

Expected behavior:
All A and B types are inferred to string[]. For types B, the type parameter U should be unified with string.

Actual behavior:
All B types are inferred to {}[].

Related Issues:
#22615 (different problem, but similar input)