Use codegen box tests for tail calls as diagnostic tests too

compiler/testData/codegen/box/functions/tailRecursion/insideElvis.kt

@@ -1,8 +1,10 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(counter : Int, a : Any) : Int? {
     if (counter < 0) return null
     if (counter == 0) return 777
 
-    return test(-1, "no tail") ?: test(-2, "no tail") ?: test(counter - 1, "tail")
+    return <!NON_TAIL_RECURSIVE_CALL!>test<!>(-1, "no tail") ?: <!NON_TAIL_RECURSIVE_CALL!>test<!>(-2, "no tail") ?: test(counter - 1, "tail")
 }
 
 fun box() : String =

compiler/testData/codegen/box/functions/tailRecursion/labeledThisReferences.kt

@@ -1,3 +1,5 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 class B {
     inner class C {
         tailRecursive fun h(counter : Int, x : Any) {
@@ -6,7 +8,7 @@ class B {
             }
         }
 
-        tailRecursive fun h2(x : Any) {
+        <!NO_TAIL_CALLS_FOUND!>tailRecursive fun h2(x : Any)<!> {
             this@B.h2("no recursion") // keep vigilance
         }
 

compiler/testData/codegen/box/functions/tailRecursion/loops.kt

@@ -1,10 +1,12 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(x : Int, a : Any) : Int {
     var z = if (x > 3) 3 else x
     while (z > 0) {
         if (z > 10) {
             return test(x - 1, "tail")
         }
-        test(0, "no tail")
+        <!NON_TAIL_RECURSIVE_CALL!>test<!>(0, "no tail")
         z = z - 1
     }
 

compiler/testData/codegen/box/functions/tailRecursion/multilevelBlocks.kt

@@ -1,10 +1,12 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(x : Int, a : Any) : Int {
     if (x == 1) {
         if (x != 1) {
-            test(0, "no tail")
+            <!NON_TAIL_RECURSIVE_CALL!>test<!>(0, "no tail")
             return test(0, "tail")
         } else {
-            return test(x + test(0, "no tail"), "tail")
+            return test(x + <!NON_TAIL_RECURSIVE_CALL!>test<!>(0, "no tail"), "tail")
         }
     } else if (x > 0) {
         return test(x - 1, "tail")

compiler/testData/codegen/box/functions/tailRecursion/realStringRepeat.kt

@@ -1,6 +1,6 @@
 tailRecursive fun String.repeat(num : Int, acc : StringBuilder = StringBuilder()) : String =
         if (num == 0) acc.toString()
-        else repeat(num - 1, acc.append(this)!!)
+        else repeat(num - 1, acc.append(this))
 
 fun box() : String {
     val s = "a".repeat(10000)

compiler/testData/codegen/box/functions/tailRecursion/recursiveInnerFunction.kt

@@ -1,3 +1,5 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 fun test() {
     [tailRecursive] fun g3(counter : Int, x : Any) {
         if (counter > 0) { g3(counter - 1, "tail") }

compiler/testData/codegen/box/functions/tailRecursion/returnInCatch.kt

@@ -1,10 +1,12 @@
-tailRecursive fun test(counter : Int, a : Any) : Int {
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+<!NO_TAIL_CALLS_FOUND!>tailRecursive fun test(counter : Int, a : Any) : Int<!> {
     if (counter == 0) return 0
 
     try {
         throw Exception()
     } catch (e : Exception) {
-        return test(counter - 1, "no tail")
+        return <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>(counter - 1, "no tail")
     }
 }
 

compiler/testData/codegen/box/functions/tailRecursion/returnInFinally.kt

@@ -1,10 +1,12 @@
-tailRecursive fun test(counter : Int, a : Any) : Int {
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+<!NO_TAIL_CALLS_FOUND!>tailRecursive fun test(counter : Int, a : Any) : Int<!> {
     if (counter == 0) return 0
 
     try {
         // do nothing
     } finally {
-        return test(counter - 1, "no tail")
+        return <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>(counter - 1, "no tail")
     }
 }
 

compiler/testData/codegen/box/functions/tailRecursion/returnInIfInFinally.kt

@@ -1,11 +1,13 @@
-tailRecursive fun test(counter : Int, a : Any) : Int {
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+<!NO_TAIL_CALLS_FOUND!>tailRecursive fun test(counter : Int, a : Any) : Int<!> {
     if (counter == 0) return 0
 
     try {
         // do nothing
     } finally {
         if (counter > 0) {
-            return test(counter - 1, "no tail")
+            return <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>(counter - 1, "no tail")
         }
     }
 

compiler/testData/codegen/box/functions/tailRecursion/returnInTry.kt

@@ -1,8 +1,10 @@
-tailRecursive fun test(counter : Int, a : Any) : Int {
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+<!NO_TAIL_CALLS_FOUND!>tailRecursive fun test(counter : Int, a : Any) : Int<!> {
     if (counter == 0) return 0
 
     try {
-        return test(counter - 1, "no tail")
+        return <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>(counter - 1, "no tail")
     } catch (any : Throwable) {
         return -1
     }

compiler/testData/codegen/box/functions/tailRecursion/simpleBlock.kt

@@ -1,7 +1,9 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(x : Int, a : Any) : Int =
     if (x == 1) {
-        test(x - 1, "no tail")
-        1 + test(x - 1, "no tail")
+        <!NON_TAIL_RECURSIVE_CALL!>test<!>(x - 1, "no tail")
+        1 + <!NON_TAIL_RECURSIVE_CALL!>test<!>(x - 1, "no tail")
     } else if (x > 0) {
         test(x - 1, "tail")
     } else {

compiler/testData/codegen/box/functions/tailRecursion/simpleReturn.kt

@@ -1,6 +1,8 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(x : Int, z : Any) : Int {
     if (x == 10) {
-        return 1 + test(x - 1, "no tail")
+        return 1 + <!NON_TAIL_RECURSIVE_CALL!>test<!>(x - 1, "no tail")
     }
     if (x > 0) {
         return test(x - 1, "tail")

compiler/testData/codegen/box/functions/tailRecursion/simpleReturnWithElse.kt

@@ -1,9 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(x : Int, a : Any) : Int {
     if (x == 0) {
         return 0
     } else if (x == 10) {
-        test(0, "no tail")
-        return 1 + test(x - 1, "no tail")
+        <!NON_TAIL_RECURSIVE_CALL!>test<!>(0, "no tail")
+        return 1 + <!NON_TAIL_RECURSIVE_CALL!>test<!>(x - 1, "no tail")
     } else {
         return test(x - 1, "tail")
     }

compiler/testData/codegen/box/functions/tailRecursion/thisReferences.kt

@@ -1,3 +1,5 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 class A {
     tailRecursive fun f1(c : Int, x : Any) {
         if (c > 0) {
@@ -11,8 +13,8 @@ class A {
         }
     }
 
-    tailRecursive fun f3(a : A, x : Any) {
-        a.f3(a, "no tail") // non-tail recursion, could be potentially resolved by condition if (a == this) f3() else a.f3()
+    <!NO_TAIL_CALLS_FOUND!>tailRecursive fun f3(a : A, x : Any)<!> {
+        a.<!NON_TAIL_RECURSIVE_CALL!>f3<!>(a, "no tail") // non-tail recursion, could be potentially resolved by condition if (a == this) f3() else a.f3()
     }
 }
 

compiler/testData/codegen/box/functions/tailRecursion/unitBlocks.kt

@@ -1,3 +1,5 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun test(x : Int, e : Any) : Unit {
     if (x == 1) {
         test(x - 1, "tail")
@@ -5,7 +7,7 @@ tailRecursive fun test(x : Int, e : Any) : Unit {
         test(x - 1, "tail")
         return
     } else if (x == 3) {
-        test(x - 1, "no tail")
+        <!NON_TAIL_RECURSIVE_CALL!>test<!>(x - 1, "no tail")
         if (x == 3) {
             test(x - 1, "tail")
         }

compiler/testData/codegen/box/functions/tailRecursion/whenWithCondition.kt

@@ -1,7 +1,9 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun withWhen(counter : Int, x : Any) : Int =
         when (counter) {
             0 -> counter
-            50 -> 1 + withWhen(counter - 1, "no tail")
+            50 -> 1 + <!NON_TAIL_RECURSIVE_CALL!>withWhen<!>(counter - 1, "no tail")
             else -> withWhen(counter - 1, "tail")
         }
 

compiler/testData/codegen/box/functions/tailRecursion/whenWithInRange.kt

@@ -1,9 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun withWhen(counter : Int, d : Any, x : Any) : Int =
         when (counter) {
             0 -> counter
             1, 2 -> withWhen(counter - 1, "1,2", "tail")
             in 3..49 -> withWhen(counter - 1, "3..49", "tail")
-            50 -> 1 + withWhen(counter - 1, "50", "no tail")
+            50 -> 1 + <!NON_TAIL_RECURSIVE_CALL!>withWhen<!>(counter - 1, "50", "no tail")
             !in 0..50 -> withWhen(counter - 1, "!0..50", "tail")
             else -> withWhen(counter - 1, "else", "tail")
         }

compiler/testData/codegen/box/functions/tailRecursion/whenWithIs.kt

@@ -1,3 +1,5 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun withWhen(counter : Int, d : Any, x : Any) : Int =
     if (counter == 0) {
         0

compiler/testData/codegen/box/functions/tailRecursion/whenWithoutCondition.kt

@@ -1,8 +1,10 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
 tailRecursive fun withWhen2(counter : Int, x : Any) : Int =
         when {
             counter == 0 -> counter
-            counter == 50 -> 1 + withWhen2(counter - 1, "no tail")
-            withWhen2(0, "no tail") == 0 -> withWhen2(counter - 1, "tail")
+            counter == 50 -> 1 + <!NON_TAIL_RECURSIVE_CALL!>withWhen2<!>(counter - 1, "no tail")
+            <!NON_TAIL_RECURSIVE_CALL!>withWhen2<!>(0, "no tail") == 0 -> withWhen2(counter - 1, "tail")
             else -> 1
         }