FIR: Prepare tree structure for safe-call refactoring

^KT-38444 In Progress

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

@@ -280,7 +280,9 @@ object BuilderConfigurator : AbstractBuilderConfigurator<FirTreeBuilder>(FirTree
             resolvedQualifier,
             resolvedReifiedParameterReference,
             expression to "FirExpressionStub",
-            varargArgumentsExpression
+            varargArgumentsExpression,
+            checkedSafeCallSubject,
+            safeCallExpression
         )
         elementsWithDefaultTypeRef.forEach {
             val (element, name) = when (it) {
@@ -375,4 +377,4 @@ object BuilderConfigurator : AbstractBuilderConfigurator<FirTreeBuilder>(FirTree
         }
     }
 
-}
+}

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

@@ -102,6 +102,8 @@ object FirTreeBuilder : AbstractFirTreeBuilder() {
     val callableReferenceAccess = element("CallableReferenceAccess", Expression, qualifiedAccessExpression)
     val thisReceiverExpression = element("ThisReceiverExpression", Expression, qualifiedAccessExpression)
     val expressionWithSmartcast = element("ExpressionWithSmartcast", Expression, qualifiedAccessExpression)
+    val safeCallExpression = element("SafeCallExpression", Expression, expression)
+    val checkedSafeCallSubject = element("CheckedSafeCallSubject", Expression, expression)
     val getClassCall = element("GetClassCall", Expression, expression, call)
     val wrappedExpression = element("WrappedExpression", Expression, expression)
     val wrappedArgumentExpression = element("WrappedArgumentExpression", Expression, wrappedExpression)

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

@@ -481,6 +481,8 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
             "FirResolvedReifiedParameterReferenceImpl",
             "FirExpressionStub",
             "FirVarargArgumentsExpressionImpl",
+            "FirSafeCallExpressionImpl",
+            "FirCheckedSafeCallSubjectImpl",
         )
         configureFieldInAllImplementations(
             field = "typeRef",

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

@@ -439,6 +439,18 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
             +field("originalType", typeRef)
         }
 
+        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)
+            // One that uses checkedReceiver as a receiver
+            +field("regularQualifiedAccess", qualifiedAccess, withReplace = true).withTransform()
+        }
+
+        checkedSafeCallSubject.configure {
+            +field("originalReceiverReference", safeCallReceiverReferenceType)
+        }
+
         callableReferenceAccess.configure {
             +field("calleeReference", namedReference, withReplace = true).withTransform()
         }

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

@@ -6,7 +6,10 @@
 package org.jetbrains.kotlin.fir.tree.generator
 
 import org.jetbrains.kotlin.contracts.description.InvocationKind
-import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationUseSiteTarget
 import org.jetbrains.kotlin.fir.tree.generator.context.generatedType
 import org.jetbrains.kotlin.fir.tree.generator.context.type
@@ -35,6 +38,8 @@ 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 firSessionType = type("fir", "FirSession")
 val emptyCfgReferenceType = generatedType("references.impl", "FirEmptyControlFlowGraphReference")
 val noReceiverExpressionType = generatedType("expressions.impl", "FirNoReceiverExpression")
@@ -71,4 +76,4 @@ val coneStubDiagnosticType = generatedType("diagnostics", "ConeStubDiagnostic")
 val dslBuilderAnnotationType = generatedType("builder", "FirBuilderDsl")
 val firImplementationDetailType = generatedType("FirImplementationDetail")
 val declarationOriginType = generatedType("declarations", "FirDeclarationOrigin")
-val declarationAttributesType = generatedType("declarations", "FirDeclarationAttributes")
+val declarationAttributesType = generatedType("declarations", "FirDeclarationAttributes")