syntax_data: {"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"I::LateParamRegion:"}]}
source_snippet:     I::LateParamRegion: HashStable<CTX>,
context_before:     I::BoundRegion: HashStable<CTX>,
context_after:     I::PlaceholderRegion: HashStable<CTX>,