Only show error on last line of block when block type does not match declared type about pie

[MeAmAnUsername]

Better solution: create a function getErrorNode : Exp -> astId that takes an expression and returns the correct error location for type errors of that expression.
A block returns the last line of the block
A function could return its own name, or maybe a specific type argument if that is return type for the function (or it could keep being just the full expression)
Other expressions should just return themselves.
Example implementation

getErrorNode(exp) = astId(exp).
getErrorNode(Call(_, name, _, _)) = astId(name). // good idea?
getErrorNode(QCall(_, name, _, _)) = astId(name). // good idea?
getErrorNode(exp@Block([])) = astId(exp).
getErrorNode(Block(lines)) = getLastLine(lines).

  getLastLine : list(Exp) -> Exp
  getLastLine([exp]) = astId(exp).
  getLastLine([_|rest@[_|_]]) = getLastLine(rest).

[MeAmAnUsername]

Given higher priority because this makes it harder to solve the root cause of the incorrect return type (the actual error cannot easily be spotted because the whole block is red)

[MeAmAnUsername]

Note: using astids as error locations currently does not work, see metaborg/nabl#74