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

compiler/testData/codegen/regressions/kt799.jet

@@ -0,0 +1,8 @@
+package kt799
+
+fun foo(b: Boolean) : String {
+    val a = if (b) true else return "false"
+    return "$a"
+}
+
+fun box() = if (foo(true) == "true" && foo(false) == "false") "OK" else "fail"

compiler/testData/diagnostics/tests/FunctionReturnTypes.jet

@@ -7,10 +7,10 @@ fun unitEmpty() : Unit {}
 fun unitEmptyReturn() : Unit {return}
 fun unitIntReturn() : Unit {return <!TYPE_MISMATCH!>1<!>}
 fun unitUnitReturn() : Unit {return #()}
-fun test1() : Any = {<!RETURN_TYPE_MISMATCH, RETURN_NOT_ALLOWED!>return<!>}
+fun test1() : Any = {<!RETURN_NOT_ALLOWED, RETURN_TYPE_MISMATCH!>return<!>}
 fun test2() : Any = @a {return@a 1}
 fun test3() : Any { <!RETURN_TYPE_MISMATCH!>return<!> }
-fun test4(): ()-> Unit = { <!RETURN_TYPE_MISMATCH, RETURN_NOT_ALLOWED!>return@test4<!> }
+fun test4(): ()-> Unit = { <!RETURN_NOT_ALLOWED, RETURN_TYPE_MISMATCH!>return@test4<!> }
 fun test5(): Any = @{ return@ }
 fun test6(): Any = {<!RETURN_NOT_ALLOWED!>return 1<!>}
 

compiler/testData/diagnostics/tests/Return.jet

@@ -9,9 +9,9 @@ class A {
                 <!RETURN_NOT_ALLOWED!>return@outer<!>
         }
         if (1 < 2)
-            <!RETURN_NOT_ALLOWED!>return@A<!>
+            <!NOT_A_RETURN_LABEL!>return@A<!>
         else if (2 < 3)
-            <!RETURN_NOT_ALLOWED!>return<!UNRESOLVED_REFERENCE!>@inner<!><!>
+            return<!UNRESOLVED_REFERENCE!>@inner<!>
         return@outer
     }
-}
+}

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) {
+}