syntax_data: {"ast_node_type":"other","tokens":[{"end":62,"kind":"keyword","start":0,"text":".with_span_note(value.span,"}]}
source_snippet:             .with_span_note(value.span, "not a function call")
context_before:             .struct_span_err(value.span, "`become` requires a function call")
context_after:             .with_span_suggestion(