[FIR] Forbid typeRef-named labels without +ContextReceivers

^KT-63068 Fixed

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/BodyResolveContext.kt

@@ -680,7 +680,7 @@ class BodyResolveContext(
                 }
                 val receiverTypeRef = function.receiverParameter?.typeRef
                 val type = receiverTypeRef?.coneType
-                val additionalLabelName = type?.labelName()
+                val additionalLabelName = type?.labelName(holder.session)
                 withLabelAndReceiverType(function.name, function, type, holder, additionalLabelName, f)
             } else {
                 f()
@@ -688,8 +688,11 @@ class BodyResolveContext(
         }
     }
 
-    private fun ConeKotlinType.labelName(): Name? {
-        return (this as? ConeLookupTagBasedType)?.lookupTag?.name
+    private fun ConeKotlinType.labelName(session: FirSession): Name? {
+        return when {
+            !session.languageVersionSettings.supportsFeature(LanguageFeature.ContextReceivers) -> null
+            else -> (this as? ConeLookupTagBasedType)?.lookupTag?.name
+        }
     }
 
     @OptIn(PrivateForInline::class)
@@ -841,7 +844,7 @@ class BodyResolveContext(
             }
             withContainer(accessor) {
                 val type = receiverTypeRef?.coneType
-                val additionalLabelName = type?.labelName()
+                val additionalLabelName = type?.labelName(holder.session)
                 withLabelAndReceiverType(property.name, property, type, holder, additionalLabelName, f)
             }
         }

compiler/testData/diagnostics/tests/extensions/contextReceivers/labelsFromClassNameForbidden.fir.kt

@@ -1,12 +1,12 @@
 // ISSUE: KT-63068
 fun List<Int>.f() {
-    this@List.size
+    this<!UNRESOLVED_LABEL!>@List<!>.size
 }
 
 <!UNSUPPORTED_FEATURE!>context(String)<!>
 fun Int.f() {
     this@String.length
-    this@Int.toDouble()
+    this<!UNRESOLVED_LABEL!>@Int<!>.toDouble()
 }
 
 <!UNSUPPORTED_FEATURE!>context(String)<!>

compiler/testData/diagnostics/tests/extensions/contextReceivers/noLabelsByClassName.fir.kt

@@ -1,28 +1,28 @@
 // ISSUE: KT-63068
 fun Int.f() {
-    this@Int
+    this<!UNRESOLVED_LABEL!>@Int<!>
 }
 
 var Int.p: Int
     get() {
-        this@Int
+        this<!UNRESOLVED_LABEL!>@Int<!>
         <!RETURN_NOT_ALLOWED!>return@p<!> 42
     }
     set(value) {
-        this@Int
+        this<!UNRESOLVED_LABEL!>@Int<!>
     }
 
 class X {
     var Int.p: Int
         get() {
-            this@Int
+            this<!UNRESOLVED_LABEL!>@Int<!>
             <!RETURN_NOT_ALLOWED!>return@p<!> 42
         }
         set(value) {
-            this@Int
+            this<!UNRESOLVED_LABEL!>@Int<!>
         }
 
     fun Int.f() {
-        this@Int
+        this<!UNRESOLVED_LABEL!>@Int<!>
     }
 }

js/js.translator/testData/box/closure/closureThisAndReceiver.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_K2: JS_IR, JS_IR_ES6
 // EXPECTED_REACHABLE_NODES: 1292
 package foo