Remove JSXMemberExpressionObject::Identifier variant

[overlookmotel]

Currently we parse all JSX member expressions as an IdentifierReference followed by one or more JSXIdentifiers.

This is the case regardless of whether the first identifier is upper case or not. i.e. foo in <foo.bar> is interpreted as an IdentifierReference, even though in <foo> it'd be a plain IdentifierName.

This behavior aligns with Babel: Babel REPL

Therefore we can remove the JSXMemberExpressionObject::Identifier variant - it's not possible to create one - it's always an IdentifierReference, another nested JSXMemberExpression, or this (#5352).

It'll be easier to do this once we've closed #5352.

[Dunqing]

I've considered it, but it doesn't work. In this case: <A.B.C />, the A is an IdentifierReference, but B isn't. Therefore, we need to keep it for nested JSXMemberExpression.

[overlookmotel]

I think it still works for <A.B.C />. The nesting is in the object field of JSXMemberExpression.

So in <A.B.C />, B and C are the property field and are JSXIdentifiers. It looks like this:

JSXMemberExpression {
    object: JSXMemberExpressionObject::MemberExpression(JSXMemberExpression {
        object: JSXMemberExpressionObject::IdentifierReference( IdentifierReference(A) ),
        property: JSXIdentifier(B),
    }),
    property: JSXIdentifier(C),
}

So, unless I'm mistaken, there are no circumstances in which JSXMemberExpressionObject::Identifier variant is ever generated by parser.

[Dunqing]

Ahh, My brain is broken. You are right.

I've made a mistake here

oxc/crates/oxc_ast/src/ast_impl/jsx.rs

Lines 63 to 65 in fe62687

	JSXMemberExpressionObject::IdentifierReference(_) => {
	unreachable!()
	}

Doesn't have any tests failed 🥲