syntax_data: {"ast_node_type":"other","tokens":[{"end":47,"kind":"keyword","start":0,"text":"#[label(mir_build_type_not_structural_def)]"}]}
source_snippet:     #[label(mir_build_type_not_structural_def)]
context_before:     pub(crate) span: Span,
context_after:     pub(crate) ty_def_span: Span,