syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"dcx.emit_err(BorrowOfLayoutConstrainedFieldRequiresUnsafe"}]}
source_snippet:                 dcx.emit_err(BorrowOfLayoutConstrainedFieldRequiresUnsafe {
context_before:             BorrowOfLayoutConstrainedField => {
context_after:                     span,