Java: load annotations methods as properties

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/lazy/descriptors/LazyJavaClassMemberScope.kt

@@ -21,22 +21,23 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.load.java.structure.*
 import org.jetbrains.kotlin.load.java.lazy.LazyJavaResolverContext
-import org.jetbrains.kotlin.descriptors.impl.ValueParameterDescriptorImpl
 import org.jetbrains.kotlin.load.java.components.TypeUsage
-import org.jetbrains.kotlin.descriptors.impl.ConstructorDescriptorImpl
 import java.util.Collections
 import org.jetbrains.kotlin.utils.*
 import java.util.ArrayList
 import org.jetbrains.kotlin.load.java.lazy.types.toAttributes
 import org.jetbrains.kotlin.resolve.DescriptorUtils
-import org.jetbrains.kotlin.descriptors.impl.EnumEntrySyntheticClassDescriptor
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.descriptors.impl.*
 import org.jetbrains.kotlin.load.java.lazy.resolveAnnotations
 import org.jetbrains.kotlin.load.java.JavaVisibilities
 import org.jetbrains.kotlin.load.java.JvmAnnotationNames
 import org.jetbrains.kotlin.load.java.descriptors.JavaConstructorDescriptor
 import org.jetbrains.kotlin.load.java.components.DescriptorResolverUtils
+import org.jetbrains.kotlin.load.java.descriptors.JavaPropertyDescriptor
+import org.jetbrains.kotlin.load.java.lazy.child
+import org.jetbrains.kotlin.resolve.DescriptorFactory
 import org.jetbrains.kotlin.types.JetType
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import java.util.LinkedHashSet
@@ -78,12 +79,36 @@ public class LazyJavaClassMemberScope(
       }
 
     override fun computeNonDeclaredProperties(name: Name, result: MutableCollection<PropertyDescriptor>) {
+        if (jClass.isAnnotationType()) {
+            computeAnnotationProperties(name, result)
+        }
+
         val propertiesFromSupertypes = getPropertiesFromSupertypes(name, getContainingDeclaration())
 
         result.addAll(DescriptorResolverUtils.resolveOverrides(name, propertiesFromSupertypes, result, getContainingDeclaration(),
                                                                    c.errorReporter))
     }
 
+    private fun computeAnnotationProperties(name: Name, result: MutableCollection<PropertyDescriptor>) {
+        val method = memberIndex().findMethodsByName(name).singleOrNull() ?: return
+        val annotations = c.resolveAnnotations(method)
+
+        val propertyDescriptor = JavaPropertyDescriptor(
+                getContainingDeclaration(), annotations, method.getVisibility(),
+                /* isVar = */ false, method.getName(), c.sourceElementFactory.source(method)
+        )
+
+        // default getter is necessary because there is no real field in annotation
+        val getter = DescriptorFactory.createDefaultGetter(propertyDescriptor)
+        propertyDescriptor.initialize(getter, null)
+
+        val returnType = computeMethodReturnType(method, annotations, c.child(propertyDescriptor, method))
+        propertyDescriptor.setType(returnType, listOf(), getDispatchReceiverParameter(), null : JetType?)
+        getter.initialize(returnType)
+
+        result.add(propertyDescriptor)
+    }
+
     private fun getPropertiesFromSupertypes(name: Name, descriptor: ClassDescriptor): Set<PropertyDescriptor> {
         return descriptor.getTypeConstructor().getSupertypes().flatMap {
             it.getMemberScope().getProperties(name).map { p -> p as PropertyDescriptor }
@@ -295,13 +320,16 @@ public class LazyJavaClassMemberScope(
     override fun getClassNames(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<Name>
             = nestedClassIndex().keySet() + enumEntryIndex().keySet()
 
-    override fun getPropertyNames(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<Name> =
-            memberIndex().getAllFieldNames() +
-            getContainingDeclaration().getTypeConstructor().getSupertypes().flatMapTo(LinkedHashSet<Name>()) { supertype ->
-                supertype.getMemberScope().getDescriptors(kindFilter, nameFilter).map { variable ->
-                    variable.getName()
-                }
+    override fun getPropertyNames(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<Name> {
+        if (jClass.isAnnotationType()) return memberIndex().getMethodNames(nameFilter)
+
+        return memberIndex().getAllFieldNames() +
+        getContainingDeclaration().getTypeConstructor().getSupertypes().flatMapTo(LinkedHashSet<Name>()) { supertype ->
+            supertype.getMemberScope().getDescriptors(kindFilter, nameFilter).map { variable ->
+                variable.getName()
             }
+        }
+    }
 
     // TODO
     override fun getImplicitReceiversHierarchy(): List<ReceiverParameterDescriptor> = listOf()

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/lazy/descriptors/LazyJavaMemberScope.kt

@@ -119,17 +119,7 @@ public abstract class LazyJavaMemberScope(
         val methodTypeParameters = method.getTypeParameters().map { p -> c.typeParameterResolver.resolveTypeParameter(p)!! }
         val valueParameters = resolveValueParameters(c, functionDescriptorImpl, method.getValueParameters())
 
-        val annotationMethod = method.getContainingClass().isAnnotationType()
-        val returnTypeAttrs = LazyJavaTypeAttributes(
-                c, method, TypeUsage.MEMBER_SIGNATURE_COVARIANT, annotations,
-                allowFlexible = !annotationMethod,
-                isForAnnotationParameter = annotationMethod
-        )
-        val returnJavaType = method.getReturnType() ?: throw IllegalStateException("Constructor passed as method: $method")
-        // Annotation arguments are never null in Java
-        val returnType = c.typeResolver.transformJavaType(returnJavaType, returnTypeAttrs).let {
-            if (annotationMethod) TypeUtils.makeNotNullable(it) else it
-        }
+        val returnType = computeMethodReturnType(method, annotations, c)
 
         val (effectiveSignature, superFunctions, signatureErrors) = resolveMethodSignature(method, methodTypeParameters, returnType, valueParameters)
 
@@ -155,6 +145,20 @@ public abstract class LazyJavaMemberScope(
         return functionDescriptorImpl
     }
 
+    protected fun computeMethodReturnType(method: JavaMethod, annotations: Annotations, c: LazyJavaResolverContext): JetType {
+        val annotationMethod = method.getContainingClass().isAnnotationType()
+        val returnTypeAttrs = LazyJavaTypeAttributes(
+                c, method, TypeUsage.MEMBER_SIGNATURE_COVARIANT, annotations,
+                allowFlexible = !annotationMethod,
+                isForAnnotationParameter = annotationMethod
+        )
+        val returnJavaType = method.getReturnType() ?: throw IllegalStateException("Constructor passed as method: $method")
+        // Annotation arguments are never null in Java
+        return c.typeResolver.transformJavaType(returnJavaType, returnTypeAttrs).let {
+            if (annotationMethod) TypeUtils.makeNotNullable(it) else it
+        }
+    }
+
     protected class ResolvedValueParameters(val descriptors: List<ValueParameterDescriptor>, val hasSynthesizedNames: Boolean)
 
     protected fun resolveValueParameters(