syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // If it looks like a width, try to be helpful.
context_before:             if looks_like_width_suffix(&['f'], suf) {
context_after:                 dcx.emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() })