Tail-call detection support in the front-end

compiler/testData/diagnostics/tests/tailRecursions/functionWithNoTails.kt

@@ -0,0 +1,3 @@
+<!NO_TAIL_CALLS_FOUND!>tailRecursive fun noTails()<!> {
+    // nothing here
+}

compiler/testData/diagnostics/tests/tailRecursions/functionWithNonTailRecursions.kt

@@ -0,0 +1,12 @@
+tailRecursive fun badTails(x : Int) : Int {
+    if (x > 0) {
+        return 1 + <!NON_TAIL_RECURSIVE_CALL!>badTails<!>(x - 1)
+    }
+    else if (x == 10) {
+        [suppress("NON_TAIL_RECURSIVE_CALL")]
+        return 1 + badTails(x - 1)
+    } else if (x == 50) {
+        return badTails(x - 1)
+    }
+    return 0
+}

compiler/testData/diagnostics/tests/tailRecursions/functionWithoutAnnotation.kt

@@ -0,0 +1,6 @@
+fun withoutAnnotation(x : Int) : Int {
+    if (x > 0) {
+        return 1 + withoutAnnotation(x - 1)
+    }
+    return 0
+}

compiler/testData/diagnostics/tests/tailRecursions/tailRecursionInFinally.kt

@@ -0,0 +1,9 @@
+<!NO_TAIL_CALLS_FOUND!>tailRecursive fun test() : Unit<!> {
+    try {
+        <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>()
+    } catch (any : Exception) {
+        <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>()
+    } finally {
+        <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>()
+    }
+}