Add ThisExpression variants to JSXElementName and JSXMemberExpressionObject

[overlookmotel]

#5223 did the bulk of the work of revamping JSXElementName (#3528). Only thing that's missing is to add:

• JSXElementName::ThisExpression
• JSXMemberExpressionObject::ThisExpression

A couple of notes:

Arrow functions transform

This code is currently broken:

oxc/crates/oxc_transformer/src/es2015/arrow_functions.rs

Lines 140 to 156 in f052a6d

	let ident = match name {
	JSXElementName::Identifier(ident) => ident,
	JSXElementName::MemberExpression(member_expr) => {
	member_expr.get_object_identifier_mut()
	}
	JSXElementName::IdentifierReference(_) | JSXElementName::NamespacedName(_) => return,
	};
	if ident.name == "this" {
	// We can't produce a proper identifier with a `ReferenceId` because `JSXIdentifier`
	// lacks that field. https://github.com/oxc-project/oxc/issues/3528
	// So generate a reference and just use its name.
	// If JSX transform is enabled, that transform runs before this and will have converted
	// this to a proper `ThisExpression`, and this visitor won't run.
	// So only a problem if JSX transform is disabled.
	let new_ident = self.get_this_name(ctx).create_read_reference(ctx);
	ident.name = new_ident.name;
	}

We can fix after we have the ThisExpression variants.

Linter

Once this is done, we can remove these lines from linter.

oxc/crates/oxc_linter/src/rules/react/jsx_no_undef.rs

Lines 60 to 64 in f052a6d

	let name = ident.name.as_str();
	// TODO: Remove this check once we have `JSXMemberExpressionObject::ThisExpression`
	if name == "this" {
	return;
	}

[Dunqing]

Before doing this, we can do some preparation work here

oxc/crates/oxc_transformer/src/es2015/arrow_functions.rs

Lines 134 to 170 in 93634bc

	/// Change <this></this> to <_this></_this>, and mark it as found
	fn enter_jsx_element_name(&mut self, name: &mut JSXElementName<'a>, ctx: &mut TraverseCtx<'a>) {
	if !self.is_inside_arrow_function() {
	return;
	}
	if let JSXElementName::Identifier(ident) = name {
	if ident.name == "this" {
	// We can't produce a proper identifier with a `ReferenceId` because `JSXIdentifier`
	// lacks that field. https://github.com/oxc-project/oxc/issues/5352
	// So generate a reference and just use its name.
	// If JSX transform is enabled, that transform runs before this and will have converted
	// this to a proper `ThisExpression`, and this visitor won't run.
	// So only a problem if JSX transform is disabled.
	let new_ident = self.get_this_name(ctx).create_read_reference(ctx);
	ident.name = new_ident.name;
	}
	}
	}
	/// Change <this.foo></this.foo> to <_this.foo></_this.foo>, and mark it as found
	fn enter_jsx_member_expression_object(
	&mut self,
	node: &mut JSXMemberExpressionObject<'a>,
	ctx: &mut TraverseCtx<'a>,
	) {
	if !self.is_inside_arrow_function() {
	return;
	}
	if let JSXMemberExpressionObject::IdentifierReference(ident) = node {
	if ident.name == "this" {
	let new_ident = self.get_this_name(ctx).create_read_reference(ctx);
	ident.name = new_ident.name;
	}
	}
	}

We should mutate node instead of mutating the node property. Because after JSXElementName::ThisExpression was added, we need to transform JSXElementName::ThisExpression to JSXElementName::IdentifierReference so that we must mutate the node itself.

[overlookmotel]

I think we were having the same thought simultaneously! #5356 (review)