FIR checker: report tailrec problems on the keyword

FE1.0 reports it on the declaration signature. This is not ideal so we
move it to the `tailrec` keyword in FIR.

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -821,8 +821,8 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         // TODO: replace with KtParameter
         val CANNOT_INFER_PARAMETER_TYPE by error<KtElement>()
 
-        val NO_TAIL_CALLS_FOUND by warning<KtNamedFunction>(PositioningStrategy.DECLARATION_SIGNATURE)
+        val NO_TAIL_CALLS_FOUND by warning<KtNamedFunction>(PositioningStrategy.TAILREC_MODIFIER)
-        val TAILREC_ON_VIRTUAL_MEMBER_ERROR by error<KtNamedFunction>(PositioningStrategy.DECLARATION_SIGNATURE)
+        val TAILREC_ON_VIRTUAL_MEMBER_ERROR by error<KtNamedFunction>(PositioningStrategy.TAILREC_MODIFIER)
         val NON_TAIL_RECURSIVE_CALL by warning<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
         val TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED by warning<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
     }

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/RegularDiagnosticData.kt

@@ -107,6 +107,7 @@ enum class PositioningStrategy(private val strategy: String? = null) {
     NON_FINAL_MODIFIER_OR_NAME,
     ENUM_MODIFIER,
     FIELD_KEYWORD,
+    TAILREC_MODIFIER,
 
     ;
 

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -442,8 +442,8 @@ object FirErrors {
     val FORBIDDEN_VARARG_PARAMETER_TYPE by error1<KtParameter, ConeKotlinType>(SourceElementPositioningStrategies.PARAMETER_VARARG_MODIFIER)
     val VALUE_PARAMETER_WITH_NO_TYPE_ANNOTATION by error0<KtParameter>()
     val CANNOT_INFER_PARAMETER_TYPE by error0<KtElement>()
-    val NO_TAIL_CALLS_FOUND by warning0<KtNamedFunction>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
+    val NO_TAIL_CALLS_FOUND by warning0<KtNamedFunction>(SourceElementPositioningStrategies.TAILREC_MODIFIER)
-    val TAILREC_ON_VIRTUAL_MEMBER_ERROR by error0<KtNamedFunction>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
+    val TAILREC_ON_VIRTUAL_MEMBER_ERROR by error0<KtNamedFunction>(SourceElementPositioningStrategies.TAILREC_MODIFIER)
     val NON_TAIL_RECURSIVE_CALL by warning0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
     val TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED by warning0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategies.kt

@@ -379,6 +379,9 @@ object LightTreePositioningStrategies {
     val ENUM_MODIFIER: LightTreePositioningStrategy =
         ModifierSetBasedLightTreePositioningStrategy(TokenSet.create(KtTokens.ENUM_KEYWORD))
 
+    val TAILREC_MODIFIER: LightTreePositioningStrategy =
+        ModifierSetBasedLightTreePositioningStrategy(TokenSet.create(KtTokens.TAILREC_KEYWORD))
+
     val FIELD_KEYWORD: LightTreePositioningStrategy = object : LightTreePositioningStrategy() {
         override fun mark(
             node: LighterASTNode,

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/SourceElementPositioningStrategies.kt

@@ -324,4 +324,9 @@ object SourceElementPositioningStrategies {
         LightTreePositioningStrategies.FIELD_KEYWORD,
         PositioningStrategies.FIELD_KEYWORD
     )
+
+    val TAILREC_MODIFIER = SourceElementPositioningStrategy(
+        LightTreePositioningStrategies.TAILREC_MODIFIER,
+        PositioningStrategies.TAILREC_MODIFIER
+    )
 }

compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/PositioningStrategies.kt

@@ -292,6 +292,9 @@ object PositioningStrategies {
     @JvmField
     val ENUM_MODIFIER: PositioningStrategy<KtModifierListOwner> = modifierSetPosition(KtTokens.ENUM_KEYWORD)
 
+    @JvmField
+    val TAILREC_MODIFIER: PositioningStrategy<KtModifierListOwner> = modifierSetPosition(KtTokens.TAILREC_KEYWORD)
+
     @JvmField
     val FIELD_KEYWORD: PositioningStrategy<KtBackingField> = object : DeclarationHeader<KtBackingField>() {
         override fun mark(element: KtBackingField): List<TextRange> {

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/functionWithNoTails.kt

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun noTails()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun noTails() {
     // nothing here
 }
 

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

@@ -16,7 +16,7 @@ class B {
             }
         }
 
-        <!NO_TAIL_CALLS_FOUND!>tailrec fun h2(x : Any)<!> {
+        <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun h2(x : Any) {
             this@B.h2("no recursion") // keep vigilance
         }
 

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/recursiveCallInLambda.kt

@@ -8,7 +8,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo() {
     bar {
         <!NON_TAIL_RECURSIVE_CALL!>foo<!>()
     }

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/recursiveCallInLocalFunction.kt

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo() {
     fun bar() {
         <!NON_TAIL_RECURSIVE_CALL!>foo<!>()
     }

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

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun test(counter : Int) : Int<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun test(counter : Int) : Int {
     if (counter == 0) return 0
 
     try {

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

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun test(counter : Int) : Int<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun test(counter : Int) : Int {
     if (counter == 0) return 0
 
     try {

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

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun test(counter : Int) : Int<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun test(counter : Int) : Int {
     if (counter == 0) return 0
 
     try {

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

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun test(counter : Int) : Int<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun test(counter : Int) : Int {
     if (counter == 0) return 0
 
     try {

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/tailRecursionInFinally.kt

@@ -6,7 +6,7 @@
 // DONT_RUN_GENERATED_CODE: JS
 // IGNORE_BACKEND: JS
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun test(go: Boolean) : Unit<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun test(go: Boolean) : Unit {
     if (!go) return
     try {
         <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>test<!>(false)

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

@@ -19,7 +19,7 @@ class A {
         }
     }
 
-    <!NO_TAIL_CALLS_FOUND!>tailrec fun f3(a : A)<!> {
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun f3(a : A) {
         a.<!NON_TAIL_RECURSIVE_CALL!>f3<!>(a) // non-tail recursion, could be potentially resolved by condition if (a == this) f3() else a.f3()
     }
 }

compiler/testData/diagnostics/tests/tailRecBasic.kt

@@ -2,17 +2,17 @@
 // WITH_STDLIB
 // !DIAGNOSTICS: -UNREACHABLE_CODE
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo1()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo1() {
     <!NON_TAIL_RECURSIVE_CALL!>foo1<!>()
     1
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo2()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo2() {
     <!NON_TAIL_RECURSIVE_CALL!>foo2<!>()
     val i = 1
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo3()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo3() {
     <!NON_TAIL_RECURSIVE_CALL!>foo3<!>()
     foo1()
 }
@@ -27,7 +27,7 @@ tailrec fun foo5() {
     foo4()
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo6(b: Boolean)<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo6(b: Boolean) {
     while (b) {
         <!NON_TAIL_RECURSIVE_CALL!>foo6<!>(!b)
     }
@@ -40,21 +40,21 @@ tailrec fun foo7_return() {
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo7_break()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo7_break() {
     while (true) {
         <!NON_TAIL_RECURSIVE_CALL!>foo7_break<!>()
         break
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo7_continue()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo7_continue() {
     while (true) {
         <!NON_TAIL_RECURSIVE_CALL!>foo7_continue<!>()
         continue
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo8()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo8() {
     while (true) {
         <!NON_TAIL_RECURSIVE_CALL!>foo8<!>()
         throw Exception()
@@ -62,19 +62,19 @@ tailrec fun foo7_return() {
     foo8()
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo9()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo9() {
     <!NON_TAIL_RECURSIVE_CALL!>foo9<!>()
     fun bar() {}
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo10()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo10() {
     <!NON_TAIL_RECURSIVE_CALL!>foo10<!>()
     class Bar {
         val i = 1
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo11(): String<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo11(): String {
     return "hello ${<!NON_TAIL_RECURSIVE_CALL!>foo11<!>()}"
 }
 

compiler/testData/diagnostics/tests/tailRecInNestedScopes.fir.kt

@@ -1,6 +1,6 @@
 // WITH_STDLIB
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo1()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo1() {
     run {
         <!NON_TAIL_RECURSIVE_CALL!>foo1<!>()
     }
@@ -9,13 +9,13 @@
 fun myRun(f: () -> Unit) = f()
 
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo2()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo2() {
     myRun {
         <!NON_TAIL_RECURSIVE_CALL!>foo2<!>()
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo3()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo3() {
     fun bar() {
         <!NON_TAIL_RECURSIVE_CALL!>foo3<!>()
     }
@@ -23,14 +23,14 @@ fun myRun(f: () -> Unit) = f()
 }
 
 class A {
-    <!NO_TAIL_CALLS_FOUND!>tailrec fun foo4()<!> {
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo4() {
         with(this) {
             <!NON_TAIL_RECURSIVE_CALL!>foo4<!>()
         }
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo5()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo5() {
     run {
         return <!NON_TAIL_RECURSIVE_CALL!>foo5<!>()
     }

compiler/testData/diagnostics/tests/tailRecInTry.kt

@@ -1,5 +1,5 @@
 // FIR_IDENTICAL
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo1()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo1() {
     try {
         <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>foo1<!>()
     } catch (e: Exception) {
@@ -9,7 +9,7 @@
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo2()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo2() {
     try {
         <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>foo2<!>()
         foo1()
@@ -22,7 +22,7 @@
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo3()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo3() {
     try {
         try {
             <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>foo3<!>()
@@ -41,7 +41,7 @@
     }
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun foo4()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo4() {
     try {
         if (true) {
             <!TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED!>foo4<!>()

compiler/testData/diagnostics/tests/tailRecOnVirtualMember.fir.kt

@@ -1,15 +1,15 @@
 //!LANGUAGE: -ProhibitTailrecOnVirtualMember
 
 open class A {
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec open fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>internal tailrec open fun bar(y: Int)<!> {
+    internal <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>protected tailrec open fun baz(y: Int)<!> {
+    protected <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun baz(y: Int) {
         baz(y)
     }
 
@@ -38,15 +38,15 @@ open class B : A() {
 
 
 open class C : A() {
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun bar(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun baz(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun baz(y: Int) {
         baz(y)
     }
 }
@@ -66,15 +66,15 @@ object D : A() {
 }
 
 sealed class E : A() {
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun bar(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun baz(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun baz(y: Int) {
         baz(y)
     }
 
@@ -109,15 +109,15 @@ enum class F {
         }
     };
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec open fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>internal tailrec open fun bar(y: Int)<!> {
+    internal <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>protected tailrec open fun baz(y: Int)<!> {
+    protected <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun baz(y: Int) {
         baz(y)
     }
 
@@ -134,15 +134,15 @@ enum class G {
 
     G1;
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec open fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>internal tailrec open fun bar(y: Int)<!> {
+    internal <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>protected tailrec open fun baz(y: Int)<!> {
+    protected <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun baz(y: Int) {
         baz(y)
     }
 
@@ -168,4 +168,4 @@ val z = object : A() {
     tailrec override fun baz(y: Int) {
         baz(y)
     }
-}
+}

compiler/testData/diagnostics/tests/tailRecOnVirtualMemberError.kt

@@ -2,15 +2,15 @@
 //!LANGUAGE: +ProhibitTailrecOnVirtualMember
 
 open class A {
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec open fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>internal tailrec open fun bar(y: Int)<!> {
+    internal <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>protected tailrec open fun baz(y: Int)<!> {
+    protected <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun baz(y: Int) {
         baz(y)
     }
 
@@ -39,15 +39,15 @@ open class B : A() {
 
 
 open class C : A() {
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun bar(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun baz(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun baz(y: Int) {
         baz(y)
     }
 }
@@ -67,15 +67,15 @@ object D : A() {
 }
 
 sealed class E : A() {
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun bar(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec override fun baz(y: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> override fun baz(y: Int) {
         baz(y)
     }
 
@@ -110,15 +110,15 @@ enum class F {
         }
     };
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec open fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>internal tailrec open fun bar(y: Int)<!> {
+    internal <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>protected tailrec open fun baz(y: Int)<!> {
+    protected <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun baz(y: Int) {
         baz(y)
     }
 
@@ -135,15 +135,15 @@ enum class G {
 
     G1;
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec open fun foo(x: Int)<!> {
+    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun foo(x: Int) {
         foo(x)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>internal tailrec open fun bar(y: Int)<!> {
+    internal <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun bar(y: Int) {
         bar(y)
     }
 
-    <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>protected tailrec open fun baz(y: Int)<!> {
+    protected <!TAILREC_ON_VIRTUAL_MEMBER_ERROR!>tailrec<!> open fun baz(y: Int) {
         baz(y)
     }
 
@@ -168,4 +168,4 @@ val z = object : A() {
     tailrec override fun baz(y: Int) {
         baz(y)
     }
-}
+}

compiler/testData/diagnostics/tests/tailRecOverridden.fir.kt

@@ -6,11 +6,11 @@ open class A {
 }
 
 class B: A() {
-    <!NO_TAIL_CALLS_FOUND!>tailrec override fun foo(x: Int)<!> {
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> override fun foo(x: Int) {
         <!NON_TAIL_RECURSIVE_CALL!>foo<!>()
     }
 
-    <!NO_TAIL_CALLS_FOUND!>tailrec override fun gav(y: Int, z: Int)<!> {
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> override fun gav(y: Int, z: Int) {
         <!NON_TAIL_RECURSIVE_CALL!>gav<!>(y)
     }
 

compiler/testData/diagnostics/tests/tailRecSingleton.fir.kt

@@ -44,7 +44,7 @@ enum class E {
         }
     },
     C {
-        <!NO_TAIL_CALLS_FOUND!>override tailrec fun rec()<!> {
+        override <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun rec() {
             C.rec() // resolution goes to `E.rec`. Hence the resolved symbol is considered different from `C.rec`.
         }
     };

compiler/testData/diagnostics/tests/tailRecWithDispatchReceiver.kt

@@ -1,6 +1,6 @@
 // FIR_IDENTICAL
 class A(val a: A) {
-    <!NO_TAIL_CALLS_FOUND!>tailrec fun foo1()<!> {
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo1() {
         a.<!NON_TAIL_RECURSIVE_CALL!>foo1<!>()
     }
 
@@ -12,7 +12,7 @@ class A(val a: A) {
         foo3()
     }
 
-    <!NO_TAIL_CALLS_FOUND!>tailrec fun foo4()<!> {
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo4() {
         with(a) {
             <!NON_TAIL_RECURSIVE_CALL!>foo4<!>()
             return

compiler/testData/diagnostics/tests/tailRecWithExtensionReceiver.kt

@@ -7,7 +7,7 @@ tailrec fun String.foo2() {
     this.foo2()
 }
 
-<!NO_TAIL_CALLS_FOUND!>tailrec fun String.foo3()<!> {
+<!NO_TAIL_CALLS_FOUND!>tailrec<!> fun String.foo3() {
     with(this) {
         <!NON_TAIL_RECURSIVE_CALL!>foo3<!>()
     }

compiler/testData/diagnostics/tests/tailRecursionComplex.kt

@@ -5,7 +5,7 @@ object O {
 }
 
 class A {
-    <!NO_TAIL_CALLS_FOUND!>tailrec fun foo(i: Int)<!> = if (i < 0) 0 else A.foo(i - 1)
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo(i: Int) = if (i < 0) 0 else A.foo(i - 1)
 
     companion object {
         fun foo(i: Int) = 42 + i
@@ -13,5 +13,5 @@ class A {
 }
 
 class B {
-    <!NO_TAIL_CALLS_FOUND!>tailrec fun foo(i: Int)<!> = if (i < 0) 0 else O.foo(i - 1)
+    <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo(i: Int) = if (i < 0) 0 else O.foo(i - 1)
-}
+}