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
+}