syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // candidate which assumes $0 == int, one that assumes `$0 ==
context_before:         // unconstrained type variable. In that case, we'll get a
context_after:         // usize`, etc. This spells an ambiguity.