Extract supertypes resolution into a separate FIR phase

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirElement.kt

@@ -28,8 +28,9 @@ interface FirElement {
     fun acceptChildren(visitor: FirVisitorVoid) =
         acceptChildren(visitor, null)
 
+    @Suppress("UNCHECKED_CAST")
     fun <E : FirElement, D> transform(visitor: FirTransformer<D>, data: D): CompositeTransformResult<E> =
-        CompositeTransformResult(accept(visitor, data))
+        accept(visitor, data) as CompositeTransformResult<E>
 
     fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement = this
-}
+}

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/FirClassLikeDeclaration.kt

@@ -5,8 +5,18 @@
 
 package org.jetbrains.kotlin.fir.declarations
 
+import org.jetbrains.kotlin.fir.symbols.ConeClassLikeSymbol
 import org.jetbrains.kotlin.fir.symbols.ConeClassifierSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirTypeAliasSymbol
 
 interface FirClassLikeDeclaration : FirMemberDeclaration {
-    val symbol: ConeClassifierSymbol
+    val symbol: ConeClassLikeSymbol
 }
+
+fun ConeClassifierSymbol.toFirClassLike(): FirClassLikeDeclaration? =
+    when (this) {
+        is FirClassSymbol -> this.fir
+        is FirTypeAliasSymbol -> this.fir
+        else -> null
+    }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/FirRegularClass.kt

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.fir.BaseTransformedType
 import org.jetbrains.kotlin.fir.VisitedSupertype
 import org.jetbrains.kotlin.fir.symbols.FirSymbolOwner
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
+import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.fir.visitors.FirVisitor
 
 // May be all containers should be properties and not base classes
@@ -32,4 +33,8 @@ interface FirRegularClass : FirClass, @VisitedSupertype FirClassLikeDeclaration,
         super<FirClassLikeDeclaration>.acceptChildren(visitor, data)
         super<FirClass>.acceptChildren(visitor, data)
     }
+
+    fun replaceSupertypes(newSupertypes: List<FirTypeRef>): FirRegularClass
 }
+
+val FirRegularClass.classId get() = symbol.classId

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/FirTypeAlias.kt

@@ -13,6 +13,8 @@ import org.jetbrains.kotlin.fir.types.coneTypeSafe
 import org.jetbrains.kotlin.fir.visitors.FirVisitor
 
 interface FirTypeAlias : FirClassLikeDeclaration, FirSymbolOwner<FirTypeAlias> {
+    fun replaceExpandTypeRef(typeRef: FirTypeRef): FirTypeAlias
+
     val expandedTypeRef: FirTypeRef
 
     override val symbol: FirTypeAliasSymbol

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/impl/FirClassImpl.kt

@@ -10,13 +10,13 @@ import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
 import org.jetbrains.kotlin.fir.transformInplace
 import org.jetbrains.kotlin.fir.types.FirTypeRef
-import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
+import org.jetbrains.kotlin.name.Name
 
 open class FirClassImpl(
     session: FirSession,
@@ -46,6 +46,11 @@ open class FirClassImpl(
 
     override val declarations = mutableListOf<FirDeclaration>()
 
+    override fun replaceSupertypes(newSupertypes: List<FirTypeRef>): FirRegularClass {
+        superTypeRefs.clear()
+        superTypeRefs.addAll(newSupertypes)
+        return this
+    }
 
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirRegularClass {
         superTypeRefs.transformInplace(transformer, data)
@@ -55,4 +60,4 @@ open class FirClassImpl(
         declarations.transformInplace(transformer, data)
         return result
     }
-}
+}

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/impl/FirTypeAliasImpl.kt

@@ -32,9 +32,14 @@ class FirTypeAliasImpl(
         symbol.bind(this)
     }
 
+    override fun replaceExpandTypeRef(typeRef: FirTypeRef): FirTypeAlias {
+        expandedTypeRef = typeRef
+        return this
+    }
+
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement {
         expandedTypeRef = expandedTypeRef.transformSingle(transformer, data)
 
         return super<FirAbstractMemberDeclaration>.transformChildren(transformer, data)
     }
-}
+}

compiler/fir/tree/visitors/org/jetbrains/kotlin/fir/visitors/CompositeTransformResult.kt

@@ -7,8 +7,7 @@ package org.jetbrains.kotlin.fir.visitors
 
 import org.jetbrains.kotlin.fir.FirElement
 
-@Suppress("UNSUPPORTED_FEATURE")
-inline class CompositeTransformResult<out T : Any>(val a: Any) {
+class CompositeTransformResult<out T : Any>(val a: Any) {
 
     companion object {
         fun <T : Any> empty() = CompositeTransformResult<T>(emptyList<T>())
@@ -33,4 +32,4 @@ inline class CompositeTransformResult<out T : Any>(val a: Any) {
 }
 
 @Suppress("NOTHING_TO_INLINE")
-inline fun <T : FirElement> T.compose() = CompositeTransformResult.single(this)
+inline fun <T : FirElement> T.compose() = CompositeTransformResult.single(this)