refactor(ast): make AST structs repr C.

Author: rzvxa

crates/oxc_ast_macros/src/lib.rs

@@ -28,8 +28,7 @@ pub fn ast(_args: TokenStream, input: TokenStream) -> TokenStream {
 
     let repr = match input {
         syn::Item::Enum(ref enum_) => enum_repr(enum_),
-        // In future, we'll add `#[repr(C)]` to structs, but at present this is disabled
-        syn::Item::Struct(_) => TokenStream2::default(),
+        syn::Item::Struct(_) => quote!(#[repr(C)]),
 
         _ => {
             unreachable!()