syntax_data: {"ast_node_type":"variable","tokens":[{"end":86,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let (source, ty) = if let ty::Adt(adt_def, ..) = source_expr.ty.kind()
context_before:                 // create all the steps directly in MIR with operations all backends need to support anyway.
context_after:                     && adt_def.is_enum()