frontend bugs fixed:

fun f(): Int = "s" //was ok
  fun g(): Int { if (1 < 2) {} else {} }//was ok
  fun h(): Int { val a = 1 } //was ok

idea/testData/checker/regression/Jet183.jet

@@ -17,6 +17,6 @@ enum class Foo<T> {
 
 
 
-fun box(): String {
+fun box() {
    val x: ProtocolState = ProtocolState.WAITING
 }