FIR: Unify all references to FIR nodes from non-parents

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/BuilderConfigurator.kt

@@ -269,6 +269,18 @@ object BuilderConfigurator : AbstractBuilderConfigurator<FirTreeBuilder>(FirTree
             defaultFalse("isNullableLHSForCallableReference")
         }
 
+//        builder(safeCallExpression) {
+//            useTypes(safeCallCheckedSubjectType)
+//        }
+//
+//        builder(checkedSafeCallSubject) {
+//            useTypes(expressionType)
+//        }
+//
+//        builder(whenSubjectExpression) {
+//            useTypes(whenExpressionType)
+//        }
+
         val elementsWithDefaultTypeRef = listOf(
             thisReceiverExpression,
             callableReferenceAccess,

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt

@@ -286,9 +286,10 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
 
         impl(whenSubjectExpression) {
             default("typeRef") {
-                value = "whenSubject.whenExpression.subject!!.typeRef"
+                value = "whenRef.value.subject!!.typeRef"
                 withGetter = true
             }
+            useTypes(whenExpressionType)
         }
 
         impl(wrappedDelegateExpression) {
@@ -443,6 +444,14 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
             }
         }
 
+        impl(safeCallExpression) {
+            useTypes(safeCallCheckedSubjectType)
+        }
+
+        impl(checkedSafeCallSubject) {
+            useTypes(expressionType)
+        }
+
         noImpl(userTypeRef)
     }
 

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/NodeConfigurator.kt

@@ -441,13 +441,13 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
         safeCallExpression.configure {
             +field("receiver", expression).withTransform()
             // Special node that might be used as a reference to receiver of a safe call after null check
-            +field("checkedSubject", safeCallCheckedSubjectReferenceType)
+            +field("checkedSubjectRef", safeCallCheckedSubjectReferenceType)
             // One that uses checkedReceiver as a receiver
             +field("regularQualifiedAccess", qualifiedAccess, withReplace = true).withTransform()
         }
 
         checkedSafeCallSubject.configure {
-            +field("originalReceiverReference", safeCallReceiverReferenceType)
+            +field("originalReceiverRef", safeCallOriginalReceiverReferenceType)
         }
 
         callableReferenceAccess.configure {
@@ -498,7 +498,7 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
         }
 
         whenSubjectExpression.configure {
-            +field("whenSubject", whenSubjectType)
+            +field("whenRef", whenRefType)
         }
 
         wrappedExpression.configure {

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/Types.kt

@@ -37,9 +37,15 @@ val classIdType = type(ClassId::class)
 val annotationUseSiteTargetType = type(AnnotationUseSiteTarget::class)
 val operationKindType = type("fir.expressions", "LogicOperationKind")
 val coneKotlinTypeType = type(ConeKotlinType::class)
-val whenSubjectType = type("fir", "FirWhenSubject")
-val safeCallReceiverReferenceType = type("fir", "FirSafeCallOriginalReceiverReference")
-val safeCallCheckedSubjectReferenceType = type("fir", "FirSafeCallCheckedSubjectReference")
+
+val whenExpressionType = generatedType("expressions", "FirWhenExpression")
+val expressionType = generatedType("expressions", "FirExpression")
+val safeCallCheckedSubjectType = generatedType("expressions", "FirCheckedSafeCallSubject")
+
+val whenRefType = generatedType("", "FirExpressionRef<FirWhenExpression>")
+val safeCallOriginalReceiverReferenceType = generatedType("", "FirExpressionRef<FirExpression>")
+val safeCallCheckedSubjectReferenceType = generatedType("", "FirExpressionRef<FirCheckedSafeCallSubject>")
+
 val firSessionType = type("fir", "FirSession")
 val emptyCfgReferenceType = generatedType("references.impl", "FirEmptyControlFlowGraphReference")
 val noReceiverExpressionType = generatedType("expressions.impl", "FirNoReceiverExpression")