{"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"if"}]}
            if prev.ty != hidden_ty.ty {
        if let Some(prev) = self.concrete_opaque_types.0.get_mut(&def_id) {
                let guar = hidden_ty.ty.error_reported().err().unwrap_or_else(|| {