FIR: make ConeSimpleKotlinType the only original for definitely not-null

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirTypeProvider.kt

@@ -135,7 +135,9 @@ internal class KtFirTypeProvider(
         return when (this) {
             // We also need to collect those on `upperBound` due to nullability.
             is ConeFlexibleType -> lowerBound.getDirectSuperTypes(shouldApproximate) + upperBound.getDirectSuperTypes(shouldApproximate)
-            is ConeDefinitelyNotNullType -> original.getDirectSuperTypes(shouldApproximate).map { ConeDefinitelyNotNullType(it) }
+            is ConeDefinitelyNotNullType -> original.getDirectSuperTypes(shouldApproximate).map {
+                ConeDefinitelyNotNullType.create(it, analysisSession.rootModuleSession.typeContext) ?: it
+            }
             is ConeIntersectionType -> intersectedTypes.asSequence().flatMap { it.getDirectSuperTypes(shouldApproximate) }
             is ConeClassErrorType -> emptySequence()
             is ConeLookupTagBasedType -> getSubstitutedSuperTypes(shouldApproximate)

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

@@ -256,7 +256,7 @@ class ConeTypeVariableType(
 
 }
 
-data class ConeDefinitelyNotNullType(val original: ConeKotlinType) : ConeSimpleKotlinType(), DefinitelyNotNullTypeMarker {
+data class ConeDefinitelyNotNullType(val original: ConeSimpleKotlinType) : ConeSimpleKotlinType(), DefinitelyNotNullTypeMarker {
     override val typeArguments: Array<out ConeTypeProjection>
         get() = original.typeArguments
 

compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/ConeInferenceContext.kt

@@ -324,7 +324,7 @@ interface ConeInferenceContext : TypeSystemInferenceExtensionContext, ConeTypeCo
 
     override fun DefinitelyNotNullTypeMarker.original(): SimpleTypeMarker {
         require(this is ConeDefinitelyNotNullType)
-        return this.original as SimpleTypeMarker
+        return this.original
     }
 
     override fun typeSubstitutorByTypeConstructor(map: Map<TypeConstructorMarker, KotlinTypeMarker>): ConeSubstitutor {

compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
 import org.jetbrains.kotlin.resolve.calls.NewCommonSuperTypeCalculator
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.model.*
+import org.jetbrains.kotlin.utils.addToStdlib.runIf
 import org.jetbrains.kotlin.fir.types.lowerBoundIfFlexible as coneLowerBoundIfFlexible
 import org.jetbrains.kotlin.fir.types.upperBoundIfFlexible as coneUpperBoundIfFlexible
 
@@ -68,15 +69,16 @@ private fun ConeTypeContext.makesSenseToBeDefinitelyNotNull(originalType: ConeKo
     }
 }
 
-// TODO: leave only one of `create` and `makeConeTypeDefinitelyNotNullOrNotNull`
 fun ConeDefinitelyNotNullType.Companion.create(
     original: ConeKotlinType,
     typeContext: ConeTypeContext
 ): ConeDefinitelyNotNullType? {
-    return when {
-        original is ConeDefinitelyNotNullType -> original
-        typeContext.makesSenseToBeDefinitelyNotNull(original) -> ConeDefinitelyNotNullType(original.coneLowerBoundIfFlexible())
-        else -> null
+    return when (original) {
+        is ConeDefinitelyNotNullType -> original
+        is ConeFlexibleType -> create(original.lowerBound, typeContext)
+        is ConeSimpleKotlinType -> runIf(typeContext.makesSenseToBeDefinitelyNotNull(original)) {
+            ConeDefinitelyNotNullType(original.coneLowerBoundIfFlexible())
+        }
     }
 }