KT-799 Allow 'return' expressions in conditionals assigned to variables

compiler/testData/diagnostics/tests/controlStructures/kt799.jet

@@ -0,0 +1,25 @@
+//KT-799 Allow 'return' expressions in conditionals assigned to variables
+
+package kt799
+
+fun test() {
+    val <!UNUSED_VARIABLE!>a<!> : Int = if (true) 6 else return // should be allowed
+
+    val <!UNUSED_VARIABLE!>b<!> = if (true) 6 else return // should be allowed
+
+    doSmth(if (true) 3 else return)
+
+    doSmth(if (true) 3 else return, <!TOO_MANY_ARGUMENTS!>1<!>)
+}
+
+val a : Nothing = <!RETURN_NOT_ALLOWED!>return 1<!>
+
+val b = <!RETURN_NOT_ALLOWED!>return 1<!>
+
+val c = doSmth(if (true) 3 else <!RETURN_NOT_ALLOWED!>return<!>)
+
+
+fun f(<!UNUSED_PARAMETER!>mi<!>: Int = if (true) 0 else <!RETURN_NOT_ALLOWED!>return<!>) {}
+
+fun doSmth(<!UNUSED_PARAMETER!>i<!>: Int) {
+}