New J2K: handle null Java type

nj2k/src/org/jetbrains/kotlin/nj2k/types/JKTypeFactory.kt

@@ -94,8 +94,7 @@ class JKTypeFactory(val symbolProvider: JKSymbolProvider) {
             }
         }
         is PsiArrayType -> JKJavaArrayType(fromPsiType(type.componentType))
-        is PsiPrimitiveType -> JKJavaPrimitiveType.KEYWORD_TO_INSTANCE[type.presentableText]
-            ?: error("Invalid primitive type ${type.presentableText}")
+        is PsiPrimitiveType -> JKJavaPrimitiveType.fromPsi(type)
         is PsiDisjunctionType ->
             JKJavaDisjunctionType(type.disjunctions.map { fromPsiType(it) })
         is PsiWildcardType ->

nj2k/src/org/jetbrains/kotlin/nj2k/types/types.kt

@@ -5,6 +5,9 @@
 
 package org.jetbrains.kotlin.nj2k.types
 
+import com.intellij.lang.jvm.types.JvmPrimitiveTypeKind
+import com.intellij.psi.PsiPrimitiveType
+import com.intellij.psi.PsiType
 import org.jetbrains.kotlin.j2k.ast.Nullability
 import org.jetbrains.kotlin.nj2k.symbols.JKClassSymbol
 import org.jetbrains.kotlin.nj2k.symbols.JKTypeParameterSymbol
@@ -65,7 +68,17 @@ data class JKCapturedType(
     override val nullability: Nullability = Nullability.Default
 ) : JKType
 
-class JKJavaPrimitiveType(val jvmPrimitiveType: JvmPrimitiveType) : JKType {
+
+sealed class JKJavaPrimitiveTypeBase : JKType {
+    abstract val jvmPrimitiveType: JvmPrimitiveType?
+}
+
+private object JKJavaNullPrimitiveType : JKJavaPrimitiveTypeBase() {
+    override val jvmPrimitiveType: JvmPrimitiveType? = null
+    override val nullability: Nullability = Nullability.Nullable
+}
+
+class JKJavaPrimitiveType private constructor(override val jvmPrimitiveType: JvmPrimitiveType) : JKJavaPrimitiveTypeBase() {
     override val nullability: Nullability
         get() = Nullability.NotNull
 
@@ -79,10 +92,20 @@ class JKJavaPrimitiveType(val jvmPrimitiveType: JvmPrimitiveType) : JKType {
         val LONG = JKJavaPrimitiveType(JvmPrimitiveType.LONG)
         val DOUBLE = JKJavaPrimitiveType(JvmPrimitiveType.DOUBLE)
 
-        val KEYWORD_TO_INSTANCE = listOf(
-            BOOLEAN, CHAR, BYTE, SHORT, INT, FLOAT, LONG, DOUBLE
-        ).associateBy { it.jvmPrimitiveType.javaKeywordName } + ("void" to JKJavaVoidType)
+        val ALL = listOf(BOOLEAN, CHAR, BYTE, SHORT, INT, FLOAT, LONG, DOUBLE)
+
+        @Suppress("UnstableApiUsage")
+        private val psiKindToJK =
+            ALL.associateBy { JvmPrimitiveTypeKind.getKindByName(it.jvmPrimitiveType.javaKeywordName) }
+
+        @Suppress("UnstableApiUsage")
+        fun fromPsi(psi: PsiPrimitiveType) = when (psi) {
+            PsiType.VOID -> JKJavaVoidType
+            PsiType.NULL -> JKJavaNullPrimitiveType
+            else -> psiKindToJK[psi.kind] ?: error("Invalid PSI type ${psi.presentableText}")
+        }
     }
+
 }
 
 data class JKJavaArrayType(

nj2k/src/org/jetbrains/kotlin/nj2k/types/typesUtils.kt

@@ -172,10 +172,11 @@ fun JKType.arrayFqName(): String =
 fun JKClassSymbol.isArrayType(): Boolean =
     fqName in arrayFqNames
 
-private val arrayFqNames = JKJavaPrimitiveType.KEYWORD_TO_INSTANCE.values
-    .filterIsInstance<JKJavaPrimitiveType>()
-    .map { PrimitiveType.valueOf(it.jvmPrimitiveType.name).arrayTypeFqName.asString() } +
-        KotlinBuiltIns.FQ_NAMES.array.asString()
+@OptIn(ExperimentalStdlibApi::class)
+private val arrayFqNames = buildList {
+    JKJavaPrimitiveType.ALL.mapTo(this) { PrimitiveType.valueOf(it.jvmPrimitiveType.name).arrayTypeFqName.asString() }
+    add(KotlinBuiltIns.FQ_NAMES.array.asString())
+}
 
 fun JKType.isArrayType() =
     when (this) {

nj2k/testData/newJ2k/types/nullType.java

@@ -0,0 +1,5 @@
+public class A {
+    void foo() {
+        Object x = true ? null : null;
+    }
+}

nj2k/testData/newJ2k/types/nullType.kt

@@ -0,0 +1,5 @@
+class A {
+    fun foo() {
+        val x: Any? = if (true) null else null
+    }
+}

nj2k/tests/org/jetbrains/kotlin/nj2k/NewJavaToKotlinConverterSingleFileTestGenerated.java

@@ -5212,6 +5212,11 @@ public class NewJavaToKotlinConverterSingleFileTestGenerated extends AbstractNew
             runTest("nj2k/testData/newJ2k/types/capturedWildcardTypeAsLambdaParameter.java");
         }
 
+        @TestMetadata("nullType.java")
+        public void testNullType() throws Exception {
+            runTest("nj2k/testData/newJ2k/types/nullType.java");
+        }
+
         @TestMetadata("recursiveType.java")
         public void testRecursiveType() throws Exception {
             runTest("nj2k/testData/newJ2k/types/recursiveType.java");