swc/crates/swc_ecma_parser/tests/tsc/overloadResolutionClassConstructors.ts

class SomeBase {
    private n;

    public s: string;
}
class SomeDerived1 extends SomeBase {
    private m;
}
class SomeDerived2 extends SomeBase {
    private m;
}
class SomeDerived3 extends SomeBase {
    private m;
}


// Ambiguous call picks the first overload in declaration order
class fn1 {
    constructor(s: string);
    constructor(s: number);
    constructor() { }
}

new fn1(undefined);

// No candidate overloads found
new fn1({}); // Error

// Generic and non - generic overload where generic overload is the only candidate when called with type arguments
class fn2<T> {
    constructor(s: string, n: number);
    constructor(n: number, t: T);
    constructor() { }
}

var d = new fn2<Date>(0, undefined);

// Generic and non - generic overload where generic overload is the only candidate when called without type arguments
var s = new fn2(0, '');

// Generic and non - generic overload where non - generic overload is the only candidate when called with type arguments
new fn2<Date>('', 0); // OK

// Generic and non - generic overload where non - generic overload is the only candidate when called without type arguments
new fn2('', 0); // OK

// Generic overloads with differing arity called without type arguments
class fn3<T, U, V> {
    constructor(n: T);
    constructor(s: string, t: T, u: U);
    constructor(v: V, u: U, t: T);
    constructor() { }
}

new fn3(3);
new fn3('', 3, '');
new fn3(5, 5, 5);

// Generic overloads with differing arity called with type arguments matching each overload type parameter count
new fn3<number>(4); // Error
new fn3<string, string>('', '', '');  // Error
new fn3<number, string, string>('', '', 3);

// Generic overloads with differing arity called with type argument count that doesn't match any overload
new fn3<number, number, number, number>(); // Error

// Generic overloads with constraints called with type arguments that satisfy the constraints
class fn4<T extends string, U extends number> {
    constructor(n: T, m: U);
    constructor() { }
}
new fn4<string, number>('', 3);
new fn4<string, number>(3, ''); // Error
new fn4<number, string>('', 3); // Error
new fn4<number, string>(3, ''); // Error

// Generic overloads with constraints called without type arguments but with types that satisfy the constraints
new fn4('', 3);
new fn4(3, ''); // Error
new fn4(3, undefined); // Error
new fn4('', null);

// Generic overloads with constraints called with type arguments that do not satisfy the constraints
new fn4<boolean, Date>(null, null); // Error

// Generic overloads with constraints called without type arguments but with types that do not satisfy the constraints
new fn4(true, null); // Error
new fn4(null, true); // Error

// Non - generic overloads where contextual typing of function arguments has errors
class fn5 {
    constructor(f: (n: string) => void);
    constructor(f: (n: number) => void);
    constructor() { return undefined; }
}
new fn5((n) => n.toFixed());
new fn5((n) => n.substr(0));
new fn5((n) => n.blah); // Error