[FIR] fix subtyping for definitely notnull types.

The current implementation doesn't consider Foo a subtype of Captured<in
Foo>!!, since AbstractTypeCheckerContext::checkSubtypeForSpecialCases
does not handle DefinitelyNotNullType cases. This PR adds handling of
DefinitelyNotNullType by looking at its original type.

^KT-42824 Fixed

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -16041,6 +16041,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 runTest("compiler/testData/codegen/box/javaInterop/generics/javaNestedSamInterface.kt");
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/IrTypeCheckerContext.kt

@@ -8,9 +8,7 @@ package org.jetbrains.kotlin.ir.types
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.types.AbstractTypeCheckerContext
-import org.jetbrains.kotlin.types.model.KotlinTypeMarker
+import org.jetbrains.kotlin.types.model.*
-import org.jetbrains.kotlin.types.model.SimpleTypeMarker
-import org.jetbrains.kotlin.types.model.TypeConstructorMarker
 
 open class IrTypeCheckerContext(override val irBuiltIns: IrBuiltIns) : IrTypeSystemContext, AbstractTypeCheckerContext() {
 
@@ -49,4 +47,15 @@ open class IrTypeCheckerContext(override val irBuiltIns: IrBuiltIns) : IrTypeSys
 
     override fun captureFromExpression(type: KotlinTypeMarker): KotlinTypeMarker? =
         error("Captured type is unsupported in IR")
+
+    override fun DefinitelyNotNullTypeMarker.original(): SimpleTypeMarker =
+        error("DefinitelyNotNull type is unsupported in IR")
+
+    override fun KotlinTypeMarker.makeDefinitelyNotNullOrNotNull(): KotlinTypeMarker {
+        error("makeDefinitelyNotNullOrNotNull is not supported in IR")
+    }
+
+    override fun SimpleTypeMarker.makeSimpleTypeDefinitelyNotNullOrNotNull(): SimpleTypeMarker {
+        error("makeSimpleTypeDefinitelyNotNullOrNotNull is not yet supported in IR")
+    }
 }

compiler/testData/codegen/box/javaInterop/generics/kt42824.kt

@@ -0,0 +1,21 @@
+// FILE: DiagnosticFactory0.java
+
+import org.jetbrains.annotations.NotNull;
+
+public class DiagnosticFactory0<E> {
+    @NotNull
+    public SimpleDiagnostic<E> on(@NotNull E element) {
+        return new SimpleDiagnostic<>(element);
+    }
+}
+
+// FILE: test.kt
+
+class SimpleDiagnostic<E>(val element: E)
+interface KtAnnotationEntry
+
+fun foo(error: DiagnosticFactory0<in KtAnnotationEntry>, entry: KtAnnotationEntry) {
+    error.on(entry) // used to be INAPPLICABLE_CANDIDATE
+}
+
+fun box() = "OK"

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -17441,6 +17441,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/javaNestedSamInterface.kt");
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -17441,6 +17441,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/javaInterop/generics/javaNestedSamInterface.kt");
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -16041,6 +16041,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/javaInterop/generics/javaNestedSamInterface.kt");
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");

core/compiler.common/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt

@@ -404,15 +404,18 @@ object AbstractTypeChecker {
 
         if (subType.isStubType() || superType.isStubType()) return isStubTypeEqualsToAnything
 
-        val superTypeCaptured = superType.asCapturedType()
+        // superType might be a definitely notNull type (see KT-42824)
+        val superOriginalType = superType.asDefinitelyNotNullType()?.original() ?: superType
+        val superTypeCaptured = superOriginalType.asCapturedType()
         val lowerType = superTypeCaptured?.lowerType()
         if (superTypeCaptured != null && lowerType != null) {
             // If superType is nullable, e.g., to check if Foo? a subtype of Captured<in Foo>?, we check the LHS, Foo?,
             // against the nullable version of the lower type of RHS. See KT-42825
-            val nullableLowerType =
+            val nullableLowerType = if (superType.isMarkedNullable()) {
-                if (superType.isMarkedNullable())
+                lowerType.withNullability(true)
-                    lowerType.withNullability(true)
+            } else {
-                else lowerType
+                if (superType.isDefinitelyNotNullType()) lowerType.makeDefinitelyNotNullOrNotNull() else lowerType
+            }
             when (getLowerCapturedTypePolicy(subType, superTypeCaptured)) {
                 CHECK_ONLY_LOWER -> return isSubtypeOf(this, subType, nullableLowerType)
                 CHECK_SUBTYPE_AND_LOWER -> if (isSubtypeOf(this, subType, nullableLowerType)) return true

core/compiler.common/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.types.model
 
 import org.jetbrains.kotlin.types.AbstractTypeCheckerContext
 import org.jetbrains.kotlin.types.Variance
-import java.util.*
 import kotlin.collections.ArrayList
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.contract
@@ -144,9 +143,6 @@ interface TypeSystemInferenceExtensionContext : TypeSystemContext, TypeSystemBui
 
     fun KotlinTypeMarker.isBuiltinFunctionalTypeOrSubtype(): Boolean
 
-    fun KotlinTypeMarker.makeDefinitelyNotNullOrNotNull(): KotlinTypeMarker
-    fun SimpleTypeMarker.makeSimpleTypeDefinitelyNotNullOrNotNull(): SimpleTypeMarker
-
     fun createCapturedType(
         constructorProjection: TypeArgumentMarker,
         constructorSupertypes: List<KotlinTypeMarker>,
@@ -171,8 +167,6 @@ interface TypeSystemInferenceExtensionContext : TypeSystemContext, TypeSystemBui
     fun CapturedTypeMarker.typeParameter(): TypeParameterMarker?
     fun CapturedTypeMarker.withNotNullProjection(): KotlinTypeMarker
 
-    fun DefinitelyNotNullTypeMarker.original(): SimpleTypeMarker
-
     fun typeSubstitutorByTypeConstructor(map: Map<TypeConstructorMarker, KotlinTypeMarker>): TypeSubstitutorMarker
     fun createEmptySubstitutor(): TypeSubstitutorMarker
 
@@ -249,6 +243,9 @@ interface TypeSystemContext : TypeSystemOptimizationContext {
     fun KotlinTypeMarker.isCapturedType() = asSimpleType()?.asCapturedType() != null
 
     fun SimpleTypeMarker.asDefinitelyNotNullType(): DefinitelyNotNullTypeMarker?
+    fun DefinitelyNotNullTypeMarker.original(): SimpleTypeMarker
+    fun KotlinTypeMarker.makeDefinitelyNotNullOrNotNull(): KotlinTypeMarker
+    fun SimpleTypeMarker.makeSimpleTypeDefinitelyNotNullOrNotNull(): SimpleTypeMarker
     fun SimpleTypeMarker.isMarkedNullable(): Boolean
     fun KotlinTypeMarker.isMarkedNullable(): Boolean =
         this is SimpleTypeMarker && isMarkedNullable()

js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java

@@ -13896,6 +13896,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
                 KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/javaInterop/generics"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JS_IR_ES6, true);
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -13896,6 +13896,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/javaInterop/generics"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JS_IR, true);
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -13961,6 +13961,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/javaInterop/generics"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JS, true);
             }
 
+            @TestMetadata("kt42824.kt")
+            public void testKt42824() throws Exception {
+                runTest("compiler/testData/codegen/box/javaInterop/generics/kt42824.kt");
+            }
+
             @TestMetadata("kt42825.kt")
             public void testKt42825() throws Exception {
                 runTest("compiler/testData/codegen/box/javaInterop/generics/kt42825.kt");