Show warnings for Java methods with external annotations when they called from Kotlin code

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/structure/impl/JavaAnnotationImpl.java

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.load.java.structure.impl;
 
+import com.intellij.codeInsight.ExternalAnnotationsManager;
 import com.intellij.psi.PsiAnnotation;
 import com.intellij.psi.PsiClass;
 import com.intellij.psi.PsiElement;
@@ -86,4 +87,11 @@ public class JavaAnnotationImpl extends JavaElementImpl<PsiAnnotation> implement
         PsiElement resolved = referenceElement.resolve();
         return resolved instanceof PsiClass ? (PsiClass) resolved : null;
     }
+
+    @Override
+    public boolean isIdeExternalAnnotation() {
+        PsiAnnotation psi = getPsi();
+        ExternalAnnotationsManager externalAnnotationManager = ExternalAnnotationsManager.getInstance(psi.getProject());
+        return externalAnnotationManager.isExternalAnnotation(psi);
+    }
 }

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/structure/impl/JavaElementCollectionFromPsiArrayUtil.kt

@@ -20,6 +20,7 @@ package org.jetbrains.kotlin.load.java.structure.impl
 
 import com.intellij.psi.*
 import com.intellij.psi.search.GlobalSearchScope
+import org.jetbrains.kotlin.load.java.NULLABILITY_ANNOTATIONS
 import org.jetbrains.kotlin.load.java.structure.*
 import org.jetbrains.kotlin.name.Name
 
@@ -67,6 +68,14 @@ internal fun classifierTypes(classTypes: Array<PsiClassType>): Collection<JavaCl
 internal fun annotations(annotations: Array<out PsiAnnotation>): Collection<JavaAnnotation> =
         annotations.convert(::JavaAnnotationImpl)
 
+internal fun nullabilityAnnotations(annotations: Array<out PsiAnnotation>): Collection<JavaAnnotation> =
+        annotations.convert(::JavaAnnotationImpl)
+                .filter { annotation ->
+                    val fqName = annotation.classId?.asSingleFqName() ?: return@filter false
+                    fqName in NULLABILITY_ANNOTATIONS
+                }
+
+
 internal fun namedAnnotationArguments(nameValuePairs: Array<PsiNameValuePair>): Collection<JavaAnnotationArgument> =
         nameValuePairs.convert { psi ->
             val name = psi.name?.let(Name::identifier)

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/structure/impl/JavaElementUtil.java

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.load.java.structure.impl;
 
+import com.intellij.codeInsight.ExternalAnnotationsManager;
 import com.intellij.psi.*;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -25,10 +26,12 @@ import org.jetbrains.kotlin.load.java.JavaVisibilities;
 import org.jetbrains.kotlin.load.java.structure.JavaAnnotation;
 import org.jetbrains.kotlin.name.FqName;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 
 import static org.jetbrains.kotlin.load.java.structure.impl.JavaElementCollectionFromPsiArrayUtil.annotations;
+import static org.jetbrains.kotlin.load.java.structure.impl.JavaElementCollectionFromPsiArrayUtil.nullabilityAnnotations;
 
 /* package */ class JavaElementUtil {
     private JavaElementUtil() {
@@ -70,6 +73,27 @@ import static org.jetbrains.kotlin.load.java.structure.impl.JavaElementCollectio
         return Collections.emptyList();
     }
 
+    @Nullable
+    private static PsiAnnotation[] getExternalAnnotations(@NotNull JavaModifierListOwnerImpl modifierListOwner) {
+        PsiModifierListOwner psiModifierListOwner = modifierListOwner.getPsi();
+        ExternalAnnotationsManager externalAnnotationManager = ExternalAnnotationsManager
+                .getInstance(psiModifierListOwner.getProject());
+        return externalAnnotationManager.findExternalAnnotations(psiModifierListOwner);
+    }
+
+    @NotNull
+    static <T extends JavaAnnotationOwnerImpl & JavaModifierListOwnerImpl>
+    Collection<JavaAnnotation> getRegularAndExternalAnnotations(@NotNull T owner) {
+        PsiAnnotation[] externalAnnotations = getExternalAnnotations(owner);
+        if (externalAnnotations == null) {
+            return getAnnotations(owner);
+        }
+        Collection<JavaAnnotation> annotations = new ArrayList<>(getAnnotations(owner));
+        annotations.addAll(nullabilityAnnotations(externalAnnotations));
+        return annotations;
+    }
+
+
     @Nullable
     public static JavaAnnotation findAnnotation(@NotNull JavaAnnotationOwnerImpl owner, @NotNull FqName fqName) {
         PsiAnnotationOwner annotationOwnerPsi = owner.getAnnotationOwnerPsi();

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/structure/impl/JavaMemberImpl.java

@@ -83,7 +83,7 @@ public abstract class JavaMemberImpl<Psi extends PsiMember> extends JavaElementI
     @NotNull
     @Override
     public Collection<JavaAnnotation> getAnnotations() {
-        return JavaElementUtil.getAnnotations(this);
+        return JavaElementUtil.getRegularAndExternalAnnotations(this);
     }
 
     @Nullable

compiler/frontend.java/src/org/jetbrains/kotlin/load/java/structure/impl/JavaValueParameterImpl.java

@@ -67,7 +67,7 @@ public class JavaValueParameterImpl extends JavaElementImpl<PsiParameter>
     @NotNull
     @Override
     public Collection<JavaAnnotation> getAnnotations() {
-        return JavaElementUtil.getAnnotations(this);
+        return JavaElementUtil.getRegularAndExternalAnnotations(this);
     }
 
     @Nullable