fix: override keyword shouldn't throw error in multilevel inherit

[HerrCai0907]

fix override keyword in following case

class A {
  foo(): void {}
}
class B extends A {
  bar(): void {}
}
class C extends B {
  override foo(): void {}. // should not throw error
}

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[dcodeIO]

Wondering why this didn't work before. Can you provide some context of what was missing exactly? Would assume that B inhereits foo from A, and then C upon extending sees foo, overriding it.

[HerrCai0907]

Wondering why this didn't work before. Can you provide some context of what was missing exactly? Would assume that B inhereits foo from A, and then C upon extending sees foo, overriding it.

But B's baseInstanceMembers don't have A's member, so need to search all the node in inherit chain and throw the error at the end.

[dcodeIO]

Oh, I see. Makes me think this is either an oversight, or perhaps we should look up from instanceMembers if these have all of them? I wonder what I was thinking when I wrote that code :)

[dcodeIO]

Looking more closely, I think markVirtuals isn't the right place to perform the check / emit the diagnostic. That's a rather specific method, and it was likely an oversight that the prior check was added there. Looks like the check should rather be performed when resolving a class.