Report warnings or errors for violated type parameter's upper bounds from Java annotated with nullability annotations

^KT-43262 Fixed

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/checkers/EnhancedUpperBoundChecker.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve.jvm.checkers
+
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.config.LanguageVersionSettings
+import org.jetbrains.kotlin.diagnostics.Errors
+import org.jetbrains.kotlin.psi.KtTypeReference
+import org.jetbrains.kotlin.resolve.BindingTrace
+import org.jetbrains.kotlin.resolve.UpperBoundChecker
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
+import org.jetbrains.kotlin.types.*
+import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
+
+class EnhancedUpperBoundChecker(override val languageVersionSettings: LanguageVersionSettings) : UpperBoundChecker {
+    override fun checkBound(
+        bound: KotlinType,
+        substitutor: TypeSubstitutor,
+        trace: BindingTrace,
+        jetTypeArgument: KtTypeReference,
+        typeArgument: KotlinType
+    ): Boolean {
+        val isCheckPassed = super.checkBound(bound, substitutor, trace, jetTypeArgument, typeArgument)
+
+        // The error is already reported, it's unnecessary to do more checks
+        if (!isCheckPassed) return false
+
+        val enhancedBound = bound.getEnhancement() ?: return false
+
+        val isTypeEnhancementImprovementsEnabled =
+            languageVersionSettings.supportsFeature(LanguageFeature.ImprovementsAroundTypeEnhancement)
+        val substitutedBound = substitutor.safeSubstitute(enhancedBound, Variance.INVARIANT)
+        if (!KotlinTypeChecker.DEFAULT.isSubtypeOf(typeArgument, substitutedBound)) {
+            if (isTypeEnhancementImprovementsEnabled) {
+                trace.report(Errors.UPPER_BOUND_VIOLATED.on(jetTypeArgument, substitutedBound, typeArgument))
+            } else {
+                trace.report(ErrorsJvm.UPPER_BOUND_VIOLATED_BASED_ON_JAVA_ANNOTATIONS.on(jetTypeArgument, substitutedBound, typeArgument))
+            }
+            return false
+        }
+        return true
+    }
+}

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/DefaultErrorMessagesJvm.java

@@ -85,6 +85,7 @@ public class DefaultErrorMessagesJvm implements DefaultErrorMessages.Extension {
         MAP.put(SUBCLASS_CANT_CALL_COMPANION_PROTECTED_NON_STATIC, "Using non-JVM static members protected in the superclass companion is unsupported yet");
 
         MAP.put(NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS, "Type mismatch: inferred type is {1} but {0} was expected", RENDER_TYPE, RENDER_TYPE);
+        MAP.put(UPPER_BOUND_VIOLATED_BASED_ON_JAVA_ANNOTATIONS, "Type argument is not within its bounds: should be subtype of ''{0}''", RENDER_TYPE, RENDER_TYPE);
         MAP.put(NULLABLE_TYPE_PARAMETER_AGAINST_NOT_NULL_TYPE_PARAMETER,
                 "Type mismatch: value of a nullable type {0} is used where non-nullable type is expected. " +
                 "This warning will become an error soon. " +

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/ErrorsJvm.java

@@ -137,6 +137,9 @@ public interface ErrorsJvm {
     DiagnosticFactory2<KtElement, KotlinType, KotlinType> NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS
             = DiagnosticFactory2.create(WARNING);
 
+    DiagnosticFactory2<KtTypeReference, KotlinType, KotlinType> UPPER_BOUND_VIOLATED_BASED_ON_JAVA_ANNOTATIONS
+            = DiagnosticFactory2.create(WARNING);
+
     DiagnosticFactory1<KtElement, KotlinType> NULLABLE_TYPE_PARAMETER_AGAINST_NOT_NULL_TYPE_PARAMETER
             = DiagnosticFactory1.create(WARNING);
 

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/platform/JvmPlatformConfigurator.kt

@@ -97,6 +97,7 @@ object JvmPlatformConfigurator : PlatformConfiguratorBase(
 ) {
     override fun configureModuleComponents(container: StorageComponentContainer) {
         container.useImpl<JvmStaticChecker>()
+        container.useImpl<EnhancedUpperBoundChecker>()
         container.useImpl<JvmReflectionAPICallChecker>()
         container.useImpl<JavaSyntheticScopes>()
         container.useImpl<SamConversionResolverImpl>()