syntax_data: {"ast_node_type":"other","tokens":[{"end":90,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                             // exactly `T` (i.e., with invariance). The variance field, in
context_before:                             // We are creating an ascription that defines the type of `x` to be
context_after:                             // contrast, is intended to be used to relate `T` to the type of