KT-234 Force when() expressions to have an 'else' branch

KT-973 Unreachable code

idea/testData/checker/Unresolved.jet

@@ -18,9 +18,9 @@ fun testUnresolved() {
     when(<error>a</error>) {
         is Int -> <error>a</error>
         is String -> <error>a</error>
+        else -> <error>a</error>
     }
 
-    //TODO
     for (j in <error>collection</error>) {
        var i: Int = j
        i += 1

idea/testData/checker/When.jet

@@ -4,7 +4,6 @@ fun foo() : Int {
     val s = ""
     val x = 1
     when (x) {
-      is * -> 1
       is <error>String</error> -> 1
       !is Int -> 1
       is Any? -> 1
@@ -16,7 +15,7 @@ fun foo() : Int {
       // Commented for KT-621 .<!error>a</!error> -> 1
       // Commented for KT-621 .equals(1).<!error>a</!error> -> 1
       // Commented for KT-621 <!warning>?.</!warning>equals(1) -> 1
-      else -> 1
+      is * -> 1
     }
 
     // Commented for KT-621
@@ -39,6 +38,7 @@ fun test() {
     x -> 1
     is 1 -> 1
     is <error>#(1, 1)</error> -> 1
+    else -> 1
   }
 
   val z = #(1, 1)
@@ -51,11 +51,12 @@ fun test() {
     is <error>#(1, "1", *)</error> -> 1
     is boo #(1, <error>"a"</error>, *) -> 1
     is boo <error>#(1, *)</error> -> 1
+    else -> 1
   }
 
   when (z) {
-    <error>else -> 1</error>
-    #(1, 1) -> 2
+    <error>else</error> -> 1
+    <error>#(1, 1) -> 2</error>
   }
 
   when (z) {

idea/testData/checker/infos/Autocasts.jet

@@ -154,11 +154,13 @@ fun toInt(i: Int?): Int = if (i != null) <info descr="Automatically cast to Int"
 fun illegalWhenBody(a: Any): Int = when(a) {
     is Int -> <info descr="Automatically cast to Int">a</info>
     is String -> <error descr="[TYPE_MISMATCH] Type mismatch: inferred type is Any but Int was expected">a</error>
+    else -> 1
 }
 fun illegalWhenBlock(a: Any): Int {
     when(a) {
         is Int -> return <info descr="Automatically cast to Int">a</info>
         is String -> return <error descr="[TYPE_MISMATCH] Type mismatch: inferred type is Any but Int was expected">a</error>
+        else -> return 1
     }
 }
 fun declarations(a: Any?) {
@@ -221,7 +223,7 @@ fun mergeAutocasts(a: Any?) {
   if (a is Int || a is String) {
     a.<error descr="Unresolved reference: compareTo">compareTo</error>("")
   }
-  when (a) {
+  <error>when</error> (a) {
     is String, is Any -> a.<error descr="Unresolved reference: compareTo">compareTo</error>("")
   }
   if (a is String && a is Any) {