Types of property 'xxx' are incompatible

[ruslanmogilevskiy]

I`m switching from TS 0.9.5 to 1.1 CTP and have this simplified .d.ts:

interface FooArray<T> extends Foo<T[]> {
    subscribeTo(transform?: (val: any) => T): FooArray<T>;
}
interface Foo<T> {
    subscribeTo(transform?: (val: any) => T): Foo<T>;
}

Compilation has failed failed with:
error TS2429: Interface 'FooArray' incorrectly extends interface 'Foo<T[]>':
Types of property 'subscribeTo' are incompatible:
Type '(transform?: (val: any) => T) => Foo' is not assignable to type '(transform?: (val: any) => T[]) => Foo<T[]>':
Types of parameters 'transform' and 'transform' are incompatible:
Type '(val: any) => T' is not assignable to type '(val: any) => T[]':
Type 'T' is not assignable to type 'T[]':
Property 'length' is missing in type '{}'.

Note that the TS 0.9.5 compiles the below code while 1.0/1.1-CTP does not.

Questions:

1. Shouldn't FooArray.subscribeTo should be treated as an overload and added to the FooArray`s contract? I.e. FooArray will have two subscribeTo methods.
2. How to fix it?

[RyanCavanaugh]

We no longer merge overloads across members like in 0.9.5. The equivalent definition would be:

interface Foo<T> {
    subscribeTo(transform?: (val: any) => T): Foo<T>;
}
interface FooArray<T> extends Foo<T> {
    subscribeTo(transform?: (val: any) => T): Foo<T>;
    subscribeTo(transform?: (val: any) => T[]): FooArray<T>;
}

[diegovilar]

@RyanCavanaugh Any specific reason for that? Makes it a copy/paste job to extend+overload interface members...

[mhegazy]

resolving overloads is order dependent, not merging results in a more predictable system.