FIR: extract initializing of containingClassAttr into fun

compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt

@@ -1019,9 +1019,7 @@ class DeclarationsConverter(
                             null, session, FirDeclarationOrigin.Source, returnType, propertyVisibility
                         ).also {
                             it.status = defaultAccessorStatus()
-                            currentDispatchReceiverType()?.lookupTag?.let { lookupTag ->
-                                it.containingClassAttr = lookupTag
-                            }
+                            it.initContainingClassAttr()
                         }
                     // NOTE: We still need the setter even for a val property so we can report errors (e.g., VAL_WITH_SETTER).
                     this.setter = convertedAccessors.find { it.isSetter }
@@ -1030,9 +1028,7 @@ class DeclarationsConverter(
                                 null, session, FirDeclarationOrigin.Source, returnType, propertyVisibility
                             ).also {
                                 it.status = defaultAccessorStatus()
-                                currentDispatchReceiverType()?.lookupTag?.let { lookupTag ->
-                                    it.containingClassAttr = lookupTag
-                                }
+                                it.initContainingClassAttr()
                             }
                         } else null
 
@@ -1176,9 +1172,7 @@ class DeclarationsConverter(
                 .also { accessor ->
                     accessor.annotations += modifiers.annotations
                     accessor.status = status
-                    currentDispatchReceiverType()?.lookupTag?.let { lookupTag ->
-                        accessor.containingClassAttr = lookupTag
-                    }
+                    accessor.initContainingClassAttr()
                 }
         }
         val target = FirFunctionTarget(labelName = null, isLambda = false)
@@ -1207,9 +1201,7 @@ class DeclarationsConverter(
             context.firFunctionTargets.removeLast()
         }.also {
             target.bind(it)
-            currentDispatchReceiverType()?.lookupTag?.let { lookupTag ->
-                it.containingClassAttr = lookupTag
-            }
+            it.initContainingClassAttr()
         }
     }
 

compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -357,9 +357,7 @@ open class RawFirBuilder(
                             this.contractDescription = it
                         }
                     }.also {
-                        currentDispatchReceiverType()?.lookupTag?.let { lookupTag ->
-                            it.containingClassAttr = lookupTag
-                        }
+                        it.initContainingClassAttr()
                         accessorTarget.bind(it)
                         this@RawFirBuilder.context.firFunctionTargets.removeLast()
                     }
@@ -382,9 +380,7 @@ open class RawFirBuilder(
                                 it.extractAnnotationsFrom(this)
                             }
                             it.status = status
-                            currentDispatchReceiverType()?.lookupTag?.let { lookupTag ->
-                                it.containingClassAttr = lookupTag
-                            }
+                            it.initContainingClassAttr()
                         }
                 }
                 else -> {

compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/BaseFirBuilder.kt

@@ -1140,6 +1140,11 @@ abstract class BaseFirBuilder<T>(val baseSession: FirSession, val context: Conte
         }
     }
 
+    protected fun FirCallableDeclaration<*>.initContainingClassAttr() {
+        val currentDispatchReceiverType = currentDispatchReceiverType() ?: return
+        containingClassAttr = currentDispatchReceiverType.lookupTag
+    }
+
     private fun FirVariable<*>.toQualifiedAccess(): FirQualifiedAccessExpression = buildQualifiedAccessExpression {
         calleeReference = buildResolvedNamedReference {
             source = this@toQualifiedAccess.source