No recovery from empty `if`

[som-snytt]

Compiler version

3.1.1

Minimized code

➜  dotty git:(feature/287) ✗ cat noend.scala

class C:
  def test = g
  def f(b: Boolean): Int =
    if b then
    end if
    42
  def g = 27
end C
➜  dotty git:(feature/287) ✗ scalac -d /tmp noend.scala
-- [E018] Syntax Error: noend.scala:5:13 --------------------------------------------------------------------------------------------------------
5 |    if b then
  |             ^
  |             expression expected but end found

longer explanation available when compiling with `-explain`
-- [E040] Syntax Error: noend.scala:10:0 --------------------------------------------------------------------------------------------------------
10 |
   |^
   |unindent expected, but eof found
-- [E006] Not Found Error: noend.scala:3:13 -----------------------------------------------------------------------------------------------------
3 |  def test = g
  |             ^
  |             Not found: g

longer explanation available when compiling with `-explain`
3 errors found

Output

   |unindent expected, but eof found

Expectation

Especially in presence of end, should not consume to eof looking for outdent. It causes cascading errors.

Expect one error at if.