`Merge` is not distributive

[TastyPi]

type Foo = { foo: "bar" } | { bar: "foo" };
type Bar = { foo: "baz" } | { baz: "qux" };

({ foo: "baz" }) satisfies Merge<Foo, Bar>;

results in error:

error TS1360: Type '{ foo: "baz"; }' does not satisfy the expected type 'Merge<Foo, Bar>'.
  Type '{ foo: "baz"; }' is not assignable to type '{ bar: "foo"; foo: "baz"; } | { bar: "foo"; baz: "qux"; } | { bar: "foo"; foo: "baz"; } | { bar: "foo"; baz: "qux"; } | { bar: "foo"; foo: "baz"; } | { bar: "foo"; baz: "qux"; } | { bar: "foo"; foo: "baz"; } | { bar: "foo"; baz: "qux"; }'.
    Property 'bar' is missing in type '{ foo: "baz"; }' but required in type '{ bar: "foo"; foo: "baz"; }'.

15 ({ foo: "baz" }) satisfies Merge<Foo, Bar>;

However, this does work:

type DistributedMerge<
  A extends object,
  B extends object,
> = A extends object ? (B extends object ? Merge<A, B> : never) : never;

type Foo = { foo: "bar" } | { bar: "foo" };
type Bar = { foo: "baz" } | { baz: "qux" };

({ foo: "baz" }) satisfies DistributiveMerge<Foo, Bar>;

[taiyakihitotsu]

You can use MergeDeep in this case.

import type {MergeDeep} from 'type-fest';

type Foo = { foo: "bar" } | { bar: "foo" };
type Bar = { foo: "baz" } | { baz: "qux" };

({ foo: "baz" }) satisfies MergeDeep<Foo, Bar>;

Is it not enough?

https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBDAnmApnA3gWRVA5igERRTAF84AzKCEOAciVQFoKUBnGOgbgFgAofozQAxCBDgBeDJTEAuOACIARgEMoCuOQA+01VHkKKYjaV58hcAEJrJ0oxAOqAXibg70cZwYCOAVwAeJmb8ABQe9o4qLpoAlHBsKjDAbBTA7HDYeITEYAA8ohAANFZqAHxcQA

PS

In both cases, @TastyPi and I posted, ({ foo: "bar"}) isn't satisfied.
(Although I don't know how the owner views the exact spec of Merge when distributing it.)

import type {MergeDeep, Merge} from 'type-fest';

type Foo = { foo: "bar" } | { bar: "foo" };
type Bar = { foo: "baz" } | { baz: "qux" };

({ foo: "bar"}) satisfies MergeDeep<Foo, Bar>; // => error
({ foo: "baz"}) satisfies MergeDeep<Foo, Bar>;

// ------------------------------------

type DistributedMerge<
  A extends object,
  B extends object,
> = A extends object ? (B extends object ? Merge<A, B> : never) : never;

type FooB = { foo: "bar" } | { bar: "foo" };
type BarB = { foo: "baz" } | { baz: "qux" };

({ foo: "bar" }) satisfies DistributedMerge<FooB, BarB>; // => error
({ foo: "baz" }) satisfies DistributedMerge<FooB, BarB>;

https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBDAnmApnA3gWRVA5igERRTABo5s8UBfOAMyghDgHIlUBaOlAZxhYDcAWABQo9mgBiECHAC8GejIBccAEQAjAIZQ1cWgB9F2qKrV0Ze6sJES4AIR3zFFiGe0AvK3CPo4nswBHAFcADysbUQAKP1d3HTVqAEo4Hi0YYB46YF4KHHwiEgAeaQhyRygAPhsYpTd1T0SUtIysnJ48qkKwEplynWrRUQB6YbgOCcmp6ZnZuaHbZDQCTJgoYA1gmBQAE0p8ItE4OABBOBRQ7YA7HY6IDQArFABjGFIjh3PLlBu7x5e3qJKs4zhdrrc4Pcnq84AB+OBRexfcF-aHweH7FBFE7lYGqK4oABuOBS+KJOEii1QcFKSIUsRUDQS+h8xh0ZlcEXESwcOjpLkZmi0XhZvn8wqCYS5YhEtTiTN0+ma6Uy2VyKz46022z2+SxtP6UHsg1lDPqQpFyVSKra6tWWq2u0xvQg9kNxoEQA

[TastyPi]

@taiyakihitotsu for my use case, I don't want to deeply merge the fields, I only want to merge at the top level (I'm essentially doing { ...a, ...b })

Also, I wouldn't expect {foo: "bar"} to be satisfied, because either the type is replaced or it also needs baz: "qux" (I probably should have used better names to make that clear).