Can't extract generic part from the function arguments in Typescript

Question

There is the basic example:

interface BasicProperties {
    a: number,
    b: number,
    c: number
}

interface Properties extends BasicProperties {
    d: number
}

function generic<T extends BasicProperties>(args: Omit<T, keyof BasicProperties> & Partial<BasicProperties>): T {
    const {
        a,
        b,
        c,
        ...other
    } = args

    const properties: Omit<T, keyof BasicProperties>= other;

    // The properties is the temporary value. It passed to a complicated function that returns the fully defined T
    // Just example:
    return {
        a: a || 0,
        b: b || 0,
        c: c || 0,
        ...properties,
    }
}

Playground.

It leads to the following error:

Type 'Omit<Omit<T, keyof BasicProperties> & Partial, "a" | "b" | "c">' is not assignable to type 'Omit<T, keyof BasicProperties>'. Type 'Exclude<keyof T, keyof BasicProperties>' is not assignable to type 'Exclude<Exclude<keyof T, keyof BasicProperties>, "a" | "b" | "c">'. Type 'keyof T' is not assignable to type 'Exclude<Exclude<keyof T, keyof BasicProperties>, "a" | "b" | "c">'. Type 'string | number | symbol' is not assignable to type 'Exclude<Exclude<keyof T, keyof BasicProperties>, "a" | "b" | "c">'. Type 'string' is not assignable to type 'Exclude<Exclude<keyof T, keyof BasicProperties>, "a" | "b" | "c">'. Type 'keyof T' is not assignable to type 'Exclude<keyof T, keyof BasicProperties>'.

What's wrong with properties type?