syntax_data: {"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // parameter environments, as an optimisation, sizedness supertraits aren't
context_before:         // PERF(sized-hierarchy): To avoid iterating over sizedness supertraits in
context_after:         // elaborated, so check if a `Sized` obligation is being elaborated to a