HL API: add nullability property to every KtType

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/components/KtTypeInfoProvider.kt

@@ -25,7 +25,7 @@ public interface KtTypeInfoProviderMixIn : KtAnalysisSessionMixIn {
     public val KtType.canBeNull: Boolean get() = analysisSession.typeInfoProvider.canBeNull(this)
 
     /** Returns true if the type is explicitly marked as nullable. This means it's safe to assign `null` to a variable with this type. */
-    public val KtType.isMarkedNullable: Boolean get() = (this as? KtTypeWithNullability)?.nullability == KtTypeNullability.NULLABLE
+    public val KtType.isMarkedNullable: Boolean get() = this.nullability == KtTypeNullability.NULLABLE
 
     public val KtType.isUnit: Boolean get() = isClassTypeWithClassId(DefaultTypeClassIds.UNIT)
     public val KtType.isInt: Boolean get() = isClassTypeWithClassId(DefaultTypeClassIds.INT)

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/types/KtType.kt

@@ -13,15 +13,14 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.Name
 
 public sealed interface KtType : ValidityTokenOwner {
+    public val nullability: KtTypeNullability
     public fun asStringForDebugging(): String
 }
 
-public interface KtTypeWithNullability : KtType {
-    public val nullability: KtTypeNullability
-}
-
 public enum class KtTypeNullability(public val isNullable: Boolean) {
-    NULLABLE(true), NON_NULLABLE(false);
+    NULLABLE(true),
+    NON_NULLABLE(false),
+    UNKNOWN(false);
 
     public companion object {
         public fun create(isNullable: Boolean): KtTypeNullability = if (isNullable) NULLABLE else NON_NULLABLE
@@ -32,7 +31,7 @@ public sealed class KtClassType : KtType {
     override fun toString(): String = asStringForDebugging()
 }
 
-public sealed class KtNonErrorClassType : KtClassType(), KtTypeWithNullability {
+public sealed class KtNonErrorClassType : KtClassType() {
     public abstract val classId: ClassId
     public abstract val classSymbol: KtClassLikeSymbol
     public abstract val typeArguments: List<KtTypeArgument>
@@ -53,7 +52,7 @@ public abstract class KtClassErrorType : KtClassType() {
     public abstract val error: String
 }
 
-public abstract class KtTypeParameterType : KtTypeWithNullability {
+public abstract class KtTypeParameterType : KtType {
     public abstract val name: Name
     public abstract val symbol: KtTypeParameterSymbol
 }
@@ -62,7 +61,7 @@ public abstract class KtCapturedType : KtType {
     override fun toString(): String = asStringForDebugging()
 }
 
-public abstract class KtDefinitelyNotNullType : KtType, KtTypeWithNullability {
+public abstract class KtDefinitelyNotNullType : KtType {
     public abstract val original: KtType
 
     final override val nullability: KtTypeNullability get() = KtTypeNullability.NON_NULLABLE

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/asJava/firLightUtils.kt

@@ -33,7 +33,6 @@ import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtTypeAndAnnotatio
 import org.jetbrains.kotlin.idea.frontend.api.types.KtNonErrorClassType
 import org.jetbrains.kotlin.idea.frontend.api.types.KtType
 import org.jetbrains.kotlin.idea.frontend.api.types.KtTypeNullability
-import org.jetbrains.kotlin.idea.frontend.api.types.KtTypeWithNullability
 import org.jetbrains.kotlin.load.kotlin.TypeMappingMode
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.SpecialNames
@@ -71,11 +70,13 @@ internal enum class NullabilityType {
     Unknown
 }
 
+//todo get rid of NullabilityType as it corresponds to KtTypeNullability
 internal val KtType.nullabilityType: NullabilityType
-    get() =
+    get() = when (nullability) {
-        (this as? KtTypeWithNullability)?.let {
+        KtTypeNullability.NULLABLE -> NullabilityType.Nullable
-            if (it.nullability == KtTypeNullability.NULLABLE) NullabilityType.Nullable else NullabilityType.NotNull
+        KtTypeNullability.NON_NULLABLE -> NullabilityType.NotNull
-        } ?: NullabilityType.Unknown
+        KtTypeNullability.UNKNOWN -> NullabilityType.Unknown
+    }
 
 
 internal fun FirMemberDeclaration.computeSimpleModality(): Set<String> {

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/types/FirKtType.kt

@@ -54,7 +54,7 @@ internal class KtFirUsualClassType(
         }
     }
 
-    override val nullability: KtTypeNullability get() = withValidityAssertion { KtTypeNullability.create(coneType.canBeNull) }
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
     override fun asStringForDebugging(): String = withValidityAssertion { coneType.render() }
     override fun equals(other: Any?) = typeEquals(other)
     override fun hashCode() = typeHashcode()
@@ -79,7 +79,7 @@ internal class KtFirFunctionalType(
         }
     }
 
-    override val nullability: KtTypeNullability get() = withValidityAssertion { KtTypeNullability.create(coneType.canBeNull) }
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
 
     override val isSuspend: Boolean get() = withValidityAssertion { coneType.isSuspendFunctionType(builder.rootSession) }
     override val arity: Int
@@ -120,6 +120,7 @@ internal class KtFirClassErrorType(
     override val coneType by weakRef(_coneType)
 
     override val error: String get() = withValidityAssertion { coneType.diagnostic.reason }
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
     override fun asStringForDebugging(): String = withValidityAssertion { coneType.render() }
     override fun equals(other: Any?) = typeEquals(other)
     override fun hashCode() = typeHashcode()
@@ -130,6 +131,7 @@ internal class KtFirCapturedType(
     override val token: ValidityToken,
 ) : KtCapturedType(), KtFirType {
     override val coneType by weakRef(_coneType)
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
     override fun asStringForDebugging(): String = withValidityAssertion { coneType.render() }
     override fun equals(other: Any?) = typeEquals(other)
     override fun hashCode() = typeHashcode()
@@ -164,7 +166,8 @@ internal class KtFirTypeParameterType(
             ?: error("Type parameter ${coneType.lookupTag} was not found")
     }
 
-    override val nullability: KtTypeNullability get() = withValidityAssertion { KtTypeNullability.create(coneType.canBeNull) }
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
+
     override fun asStringForDebugging(): String = withValidityAssertion { coneType.render() }
     override fun equals(other: Any?) = typeEquals(other)
     override fun hashCode() = typeHashcode()
@@ -180,6 +183,9 @@ internal class KtFirFlexibleType(
 
     override val lowerBound: KtType by cached { builder.typeBuilder.buildKtType(coneType.lowerBound) }
     override val upperBound: KtType by cached { builder.typeBuilder.buildKtType(coneType.upperBound) }
+
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
+
     override fun asStringForDebugging(): String = withValidityAssertion { coneType.render() }
     override fun equals(other: Any?) = typeEquals(other)
     override fun hashCode() = typeHashcode()
@@ -197,7 +203,15 @@ internal class KtFirIntersectionType(
         coneType.intersectedTypes.map { conjunct -> builder.typeBuilder.buildKtType(conjunct) }
     }
 
+    override val nullability: KtTypeNullability get() = withValidityAssertion { coneType.nullability.asKtNullability() }
+
     override fun asStringForDebugging(): String = withValidityAssertion { coneType.render() }
     override fun equals(other: Any?) = typeEquals(other)
     override fun hashCode() = typeHashcode()
 }
+
+private fun ConeNullability.asKtNullability(): KtTypeNullability = when (this) {
+    ConeNullability.NULLABLE -> KtTypeNullability.NULLABLE
+    ConeNullability.UNKNOWN -> KtTypeNullability.UNKNOWN
+    ConeNullability.NOT_NULL -> KtTypeNullability.NON_NULLABLE
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/utils/firUtils.kt

@@ -95,4 +95,5 @@ internal fun FirExpression.convertConstantExpression(): KtConstantValue =
 internal fun KtTypeNullability.toConeNullability() = when (this) {
     KtTypeNullability.NULLABLE -> ConeNullability.NULLABLE
     KtTypeNullability.NON_NULLABLE -> ConeNullability.NOT_NULL
+    KtTypeNullability.UNKNOWN -> ConeNullability.UNKNOWN
 }