Allow missing properties that are set later in the same scope

[Seb-C]

Thank you for this analyzer, it's very useful.

In constructors, I very often need to setup many things, sometimes which refer to the struct itself (in order to reuse code, setup destructors, start goroutines...).

It's not always possible to reorganize such methods to set all the properties at once. So I was wondering if it would be possible to allow such pattern whenever it's done in the same scope?

Example:

struct Foo{
    a int
    b string
}

func NewFoo() Foo {
    foo := Foo{
        a: 42,
    }
    foo.b = foo.someMethod()

    return foo
}

[Seb-C]

An alternative idea for this issue could be to add comments to ignore the error on some properties only. I am guessing that this could be easier to implement:

struct Foo{
    propA int
    propB int
    propC int
    propD int
    propE int
}

func NewFoo() Foo {
    //exhaustruct:ignore propB, propC
    foo := Foo{
        propA: 1,
        propD: 4,
    }
    foo.b = foo.someMethod()
    foo.c = foo.anotherThing()

    return foo
}

➡ This would only output an error for the missing propE, but not for propB or propC.

func NewFoo() Foo {
    //exhaustruct:ignore propB, propC
    foo := Foo{
        propA: 1,
        propD: 4,
        propE: 5,
    }
    foo.b = foo.someMethod()
    foo.c = foo.anotherThing()

    return foo
}

➡ This would not output any error

[xobotyi]

Yeah, as I outlined in #123 - I'm planning to implement such thing. But currently it looks like nightmare to implement. Though, Im not given up on this idea yet)