Non-nullary apply is permitted on dotty nullary method overriding java method

[olafurpg]

Copy-pasteable repro.

cat << EOF > Fuzbar.java
package fuz;
public interface Fuzbar {
  public String str();
}
EOF
cat << EOF > a.scala
object a extends fuz.Fuzbar {
  override def str = ""
  str()()()()()()
}
EOF
dotc a.scala Fuzbar.java
// compiles OK, expected error
$ dotc -version
0.4.0-bin-SNAPSHOT-nonbootstrapped-git-d70b8f4

I expected dotty to report an error like below

-- Error: a.scala:5:6 ----------------------------------------------------------
5 |  str()()()()
  |  ^^^^^
  |  missing argument for parameter index of method apply: (index: Int): Char

Related #2570