[ "let"; var = possibly_typed_name; SYMBOL <:unicode<def>> (* ≝ *);
p1 = term; "in"; p2 = term ->
return_term loc (Ast.LetIn (var, p1, p2))
[ "let"; var = possibly_typed_name; SYMBOL <:unicode<def>> (* ≝ *);
p1 = term; "in"; p2 = term ->
return_term loc (Ast.LetIn (var, p1, p2))