FIR: refactor cone types (arguments, projections)

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeTypes.kt

@@ -9,27 +9,46 @@ import org.jetbrains.kotlin.fir.symbols.ConeClassLikeSymbol
 import org.jetbrains.kotlin.fir.symbols.ConeSymbol
 import org.jetbrains.kotlin.fir.symbols.ConeTypeParameterSymbol
 
-sealed class ConeKotlinTypeProjection(val kind: ProjectionKind)
+sealed class ConeKotlinTypeProjection {
+    abstract val kind: ProjectionKind
+
+    companion object {
+        val EMPTY_ARRAY = arrayOf<ConeKotlinTypeProjection>()
+    }
+}
 
 enum class ProjectionKind {
     STAR, IN, OUT, INVARIANT
 }
 
-object StarProjection : ConeKotlinTypeProjection(ProjectionKind.STAR)
-
-abstract class ConeKotlinTypeProjectionIn : ConeKotlinTypeProjection(ProjectionKind.IN) {
-    abstract val type: ConeKotlinType
+object StarProjection : ConeKotlinTypeProjection() {
+    override val kind: ProjectionKind
+        get() = ProjectionKind.STAR
 }
 
-abstract class ConeKotlinTypeProjectionOut : ConeKotlinTypeProjection(ProjectionKind.OUT) {
-    abstract val type: ConeKotlinType
+class ConeKotlinTypeProjectionIn(val type: ConeKotlinType) : ConeKotlinTypeProjection() {
+    override val kind: ProjectionKind
+        get() = ProjectionKind.IN
+}
+
+class ConeKotlinTypeProjectionOut(val type: ConeKotlinType) : ConeKotlinTypeProjection() {
+    override val kind: ProjectionKind
+        get() = ProjectionKind.OUT
 }
 
 // We assume type IS an invariant type projection to prevent additional wrapper here
 // (more exactly, invariant type projection contains type)
-sealed class ConeKotlinType : ConeKotlinTypeProjection(ProjectionKind.INVARIANT)
+sealed class ConeKotlinType : ConeKotlinTypeProjection() {
+    override val kind: ProjectionKind
+        get() = ProjectionKind.INVARIANT
+
+    abstract val typeArguments: Array<out ConeKotlinTypeProjection>
+}
 
 class ConeKotlinErrorType(val reason: String) : ConeKotlinType() {
+    override val typeArguments: Array<out ConeKotlinTypeProjection>
+        get() = EMPTY_ARRAY
+
     override fun toString(): String {
         return "<ERROR TYPE: $reason>"
     }
@@ -38,8 +57,9 @@ class ConeKotlinErrorType(val reason: String) : ConeKotlinType() {
 class ConeClassErrorType(val reason: String) : ConeClassLikeType() {
     override val symbol: ConeClassLikeSymbol
         get() = error("!")
-    override val typeArguments: List<ConeKotlinTypeProjection>
-        get() = emptyList()
+
+    override val typeArguments: Array<out ConeKotlinTypeProjection>
+        get() = EMPTY_ARRAY
 
     override fun toString(): String {
         return "<ERROR CLASS: $reason>"
@@ -52,8 +72,6 @@ sealed class ConeSymbolBasedType : ConeKotlinType() {
 
 abstract class ConeClassLikeType : ConeSymbolBasedType() {
     abstract override val symbol: ConeClassLikeSymbol
-
-    abstract val typeArguments: List<ConeKotlinTypeProjection>
 }
 
 abstract class ConeAbbreviatedType : ConeClassLikeType() {

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/impl/ConeFunctionTypeImpl.kt

@@ -7,9 +7,13 @@ package org.jetbrains.kotlin.fir.types.impl
 
 import org.jetbrains.kotlin.fir.types.ConeFunctionType
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.ConeKotlinTypeProjection
 
 class ConeFunctionTypeImpl(
     override val receiverType: ConeKotlinType?,
     override val parameterTypes: List<ConeKotlinType>,
     override val returnType: ConeKotlinType
-) : ConeFunctionType()
+) : ConeFunctionType() {
+    override val typeArguments: Array<out ConeKotlinTypeProjection>
+        get() = EMPTY_ARRAY
+}

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/impl/Impl.kt

@@ -11,20 +11,19 @@ import org.jetbrains.kotlin.fir.types.*
 
 open class ConeClassTypeImpl(
     override val symbol: ConeClassLikeSymbol,
-    override val typeArguments: List<ConeKotlinTypeProjection>
+    override val typeArguments: Array<ConeKotlinTypeProjection>
 ) : ConeClassLikeType()
 
-class ConeKotlinTypeProjectionInImpl(override val type: ConeKotlinType) : ConeKotlinTypeProjectionIn()
-
-class ConeKotlinTypeProjectionOutImpl(override val type: ConeKotlinType) : ConeKotlinTypeProjectionOut()
-
 class ConeAbbreviatedTypeImpl(
     override val abbreviationSymbol: ConeClassLikeSymbol,
-    override val typeArguments: List<ConeKotlinTypeProjection>,
+    override val typeArguments: Array<ConeKotlinTypeProjection>,
     override val directExpansion: ConeClassLikeType
 ) : ConeAbbreviatedType() {
     override val symbol: ConeClassLikeSymbol
         get() = abbreviationSymbol
 }
 
-class ConeTypeParameterTypeImpl(override val symbol: ConeTypeParameterSymbol) : ConeTypeParameterType()
+class ConeTypeParameterTypeImpl(override val symbol: ConeTypeParameterSymbol) : ConeTypeParameterType() {
+    override val typeArguments: Array<out ConeKotlinTypeProjection>
+        get() = EMPTY_ARRAY
+}

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/deserialization/FirTypeDeserializer.kt

@@ -13,8 +13,6 @@ import org.jetbrains.kotlin.fir.symbols.LibraryTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.impl.ConeAbbreviatedTypeImpl
 import org.jetbrains.kotlin.fir.types.impl.ConeClassTypeImpl
-import org.jetbrains.kotlin.fir.types.impl.ConeKotlinTypeProjectionInImpl
-import org.jetbrains.kotlin.fir.types.impl.ConeKotlinTypeProjectionOutImpl
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.*
 import org.jetbrains.kotlin.serialization.deserialization.ProtoEnumFlags
@@ -78,7 +76,7 @@ class FirTypeDeserializer(
 
         val arguments = proto.collectAllArguments().mapIndexed { index, proto ->
             typeArgument(constructor.typeParameters.getOrNull(index), proto)
-        }.toList()
+        }.toTypedArray()
 
         val simpleType = if (Flags.SUSPEND_TYPE.get(proto.flags)) {
             //createSuspendFunctionType(annotations, constructor, arguments, proto.nullable)
@@ -121,8 +119,8 @@ class FirTypeDeserializer(
         val coneType = type(type)
         return when (projection) {
             Variance.INVARIANT -> coneType
-            Variance.IN_VARIANCE -> ConeKotlinTypeProjectionInImpl(coneType)
-            Variance.OUT_VARIANCE -> ConeKotlinTypeProjectionOutImpl(coneType)
+            Variance.IN_VARIANCE -> ConeKotlinTypeProjectionIn(coneType)
+            Variance.OUT_VARIANCE -> ConeKotlinTypeProjectionOut(coneType)
         }
     }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/impl/FirTypeResolverImpl.kt

@@ -25,14 +25,14 @@ class FirTypeResolverImpl : FirTypeResolver {
                     val type = (it.type as FirResolvedType).type
                     when (it.variance) {
                         Variance.INVARIANT -> type
-                        Variance.IN_VARIANCE -> ConeKotlinTypeProjectionInImpl(type)
-                        Variance.OUT_VARIANCE -> ConeKotlinTypeProjectionOutImpl(type)
+                        Variance.IN_VARIANCE -> ConeKotlinTypeProjectionIn(type)
+                        Variance.OUT_VARIANCE -> ConeKotlinTypeProjectionOut(type)
                     }
                 }
                 else -> error("!")
             }
         }
-    }
+    }.toTypedArray()
 
     private fun ConeSymbol.toConeKotlinType(parts: List<FirQualifierPart>): ConeKotlinType? {
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/impl/FirBuiltinType.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.expressions.FirAnnotationCall
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.ConeKotlinTypeProjection
 import org.jetbrains.kotlin.fir.types.FirResolvedType
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
@@ -27,7 +28,7 @@ sealed class FirBuiltinType(
                 Name.identifier(name)
             )
         ),
-        emptyList()
+        ConeKotlinTypeProjection.EMPTY_ARRAY
     )
 
     final override val isNullable = false