GROOVY-7814: Support Arrays of arbitrary annotations as the return ty…

src/main/org/codehaus/groovy/classgen/AnnotationVisitor.java

@@ -194,6 +194,12 @@ private static boolean isValidAnnotationClass(ClassNode node) {
         return node.implementsInterface(ClassHelper.Annotation_TYPE);
     }
 
+    private boolean isValidAnnotationClassOrAnnotationInterface(ClassNode node) {
+        // the java.lang.annotation.Annotation interface (ClassHelper.Annotation_TYPE)
+        // can be used to indicate that any annotation is allowed
+        return isValidAnnotationClass(node) || ClassHelper.Annotation_TYPE.equals(node);
+    }
+
     protected void visitExpression(String attrName, Expression attrExp, ClassNode attrType) {
         if (attrType.isArray()) {
             // check needed as @Test(attr = {"elem"}) passes through the parser
@@ -225,7 +231,7 @@ protected void visitExpression(String attrName, Expression attrExp, ClassNode at
             } else {
                 addError("Expected enum value for attribute " + attrName, attrExp);
             }
-        } else if (isValidAnnotationClass(attrType)) {
+        } else if (isValidAnnotationClassOrAnnotationInterface(attrType)) {
             if (attrExp instanceof AnnotationConstantExpression) {
                 visitAnnotationExpression(attrName, (AnnotationConstantExpression) attrExp, attrType);
             } else {
@@ -247,7 +253,7 @@ public void checkReturnType(ClassNode attrType, ASTNode node) {
             return;
         } else if (attrType.isDerivedFrom(ClassHelper.Enum_Type)) {
             return;
-        } else if (isValidAnnotationClass(attrType)) {
+        } else if (isValidAnnotationClassOrAnnotationInterface(attrType)) {
             return;
         } else {
             addError("Unexpected return type " + attrType.getName(), node);

src/test/gls/annotations/AnnotationTest.groovy

@@ -678,6 +678,22 @@ class AnnotationTest extends CompilableTestSupport {
         '''
     }
 
+    // GROOVY-7814
+    void testAnyAnnotations() {
+        assertScript '''
+        @gls.annotations.AnyAnnotationCollection([
+            @Grab('foo:bar:1.0'),
+            @gls.annotations.AnyAnnotationCollection([
+                @Deprecated
+            ])
+        ])
+        class Dummy{}
+
+        assert Dummy.annotations[0].value().size() == 2
+        assert Dummy.annotations[0].value()[1].value()[0].annotationType().simpleName == 'Deprecated'
+        '''
+    }
+
     //Parametrized tests in Spock would allow to make it much more readable
     private static String codeWithMetaAnnotationWithTarget(String targetElementTypeName) {
         """

src/test/gls/annotations/AnyAnnotationCollection.groovy

@@ -0,0 +1,32 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package gls.annotations
+
+import java.lang.annotation.Annotation
+import java.lang.annotation.Retention
+import java.lang.annotation.Target
+
+import static java.lang.annotation.ElementType.TYPE
+import static java.lang.annotation.RetentionPolicy.RUNTIME
+
+@Retention(RUNTIME)
+@Target([TYPE])
+@interface AnyAnnotationCollection {
+    Annotation[] value()
+}