fix for KT-241

idea/testData/codegen/controlStructures/forUserType.jet

@@ -0,0 +1,45 @@
+fun box() : String {
+    val c5 = MyCollection3()
+    for (el in c5) {}
+
+    val c1: java.lang.Iterable<Int> = MyCollection1()
+    for (el in c1) {}
+
+    val c2 = MyCollection1()
+    for (el in c2) {}
+/*
+    val c3: Iterable<Int> = MyCollection2()
+    for (el in c3) {}
+
+    val c4 = MyCollection2()
+    for (el in c4) {}
+*/
+    return "OK"
+}
+
+class MyCollection1(): java.lang.Iterable<Int> {
+    fun iterator(): java.util.Iterator<Int> = MyIterator()
+
+    class MyIterator(): java.util.Iterator<Int> {
+        fun next() = 0
+        fun hasNext() = false
+    }
+}
+
+class MyCollection2(): Iterable<Int> {
+    fun iterator(): Iterator<Int> = MyIterator()
+
+    class MyIterator(): Iterator<Int> {
+        fun next() = 0
+        fun hasNext() = false
+    }
+}
+
+class MyCollection3() {
+    fun iterator() = MyIterator()
+
+    class MyIterator() {
+        fun next() = 0
+        fun hasNext() = false
+    }
+}

idea/testData/codegen/regressions/kt259.jet

@@ -39,6 +39,11 @@ fun t3 () : Boolean {
     if(d.isT(10))     return false
     if(!d.isT(null))  return false
 
+    val f = B<java.lang.String?>()
+    if(!f.isT("aaa")) return false
+    if(f.isT(10))     return false
+    if(!f.isT(null))  return false
+
     val c = B<Int>()
     if(c.isT("aaa")) return false
     if(!c.isT(10))   return false