1719.lean:2:8-2:12: error(lean.invalidDottedIdent): Invalid dotted identifier notation: The expected type of `.inl` could not be determined

Hint: Using one of these would be unambiguous:
  [apply] `Or.inl`
  [apply] `PSum.inl`
  [apply] `Sum.inl`
  [apply] `Sum.Lex.inl`
  [apply] `Sum.LiftRel.inl`