syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                     // new error args for the missing generics.
context_before:                     // If this is an ill-formed auto/built-in trait, then synthesize
context_after:                     let err_args = ty::GenericArgs::extend_with_error(