To elaborate is to read a C expression into its typed tree, the frontend's step between parsing and lowering (c_types:elaborate/3c_types.plelaborate+E, +Env, -XsemidetX is E as C reads it: each node typed, and lvalues, function designators and values told apart. Fails when E cannot be typed.). The formal model has no counterpart: it starts at the IR. See guide.md, 4. Types and elaboration.