syntax_data: {"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // Instead, pass just the data pointer, but give it the type `*const/mut dyn Trait`
context_before:             // Don't pass the vtable, it's not an argument of the virtual fn.
context_after:             // or `&/&mut dyn Trait` because this is special-cased elsewhere in codegen