syntax_data: {"ast_node_type":"other","tokens":[{"end":90,"kind":"keyword","start":0,"text":"FloatConv::MixedPair"}]}
source_snippet:             FloatConv::MixedPair { first_ty, second_ty_offset_from_start, second_ty } => {
context_before:             }
context_after:                 arg.cast_to(CastTarget::offset_pair(