The command has indeed failed with message:
The following term contains unresolved implicit arguments:
  (fun p : point2d => {| x2p := x2p p + 1; y2p := ?y2p |})
More precisely: 
- ?y2p: Cannot infer field y2p of record point2d in environment:
  p : point2d
The command has indeed failed with message:
The following term contains unresolved implicit arguments:
  (fun p : point2d => {| x2p := x2p p + (fun n : nat => ?n) 1; y2p := ?y2p |})
More precisely: 
- ?n: Cannot infer this placeholder of type "nat" in
  environment:
  p : point2d
  n : nat
- ?y2p: Cannot infer field y2p of record point2d in environment:
  p : point2d