KotlinLanguageInjector: support for nested annotations (#KT-21753)

idea/idea-jvm/src/org/jetbrains/kotlin/idea/injection/KotlinLanguageInjector.kt

@@ -276,9 +276,14 @@ class KotlinLanguageInjector(
     private fun injectInAnnotationCall(host: KtElement): InjectionInfo? {
         if (!annotationInjectionsEnabled) return null
         val argument = host.parent as? KtValueArgument ?: return null
-        val annotationEntry = argument.parent.parent as? KtAnnotationEntry ?: return null
+        val annotationEntry = argument.parent.parent as? KtCallElement ?: return null
         if (!fastCheckInjectionsExists(annotationEntry)) return null
-        val calleeReference = annotationEntry.calleeExpression?.constructorReferenceExpression?.mainReference
+        val calleeExpression = annotationEntry.calleeExpression ?: return null
+        val calleeReference = when (calleeExpression) {
+            is KtConstructorCalleeExpression -> calleeExpression.constructorReferenceExpression?.mainReference // for top annotations
+            is KtNameReferenceExpression -> calleeExpression.mainReference // for nested annotations
+            else -> return null
+        }
         val callee = calleeReference?.resolve()
         when (callee) {
             is KtFunction -> return injectionForKotlinCall(argument, callee, calleeReference)
@@ -378,8 +383,13 @@ class KotlinLanguageInjector(
                                    }, configuration)
                                }, false)
 
-    private fun fastCheckInjectionsExists(annotationEntry: KtAnnotationEntry): Boolean {
-        val referencedName = (annotationEntry.typeReference?.typeElement as? KtUserType)?.referencedName ?: return false
+    private fun fastCheckInjectionsExists(annotationEntry: KtCallElement): Boolean {
+        val referencedName = when (annotationEntry) {
+            is KtAnnotationEntry -> // for top annotations
+                (annotationEntry.typeReference?.typeElement as? KtUserType)?.referencedName ?: return false
+            else -> // for nested annotations
+                (annotationEntry.calleeExpression as? KtNameReferenceExpression)?.getReferencedName() ?: return false
+        }
         val annotationShortName = annotationEntry.containingKtFile.aliasImportMap()[referencedName].singleOrNull() ?: referencedName
         return annotationShortName in injectableTargetClassShortNames.value
     }

idea/tests/org/jetbrains/kotlin/psi/KotlinInjectionTest.kt

@@ -519,6 +519,39 @@ class KotlinInjectionTest : AbstractInjectionTest() {
                                             """)
     }
 
+    fun testInjectionInJavaNestedAnnotation() {
+        myFixture.addClass(
+            """
+                            package myinjection;
+
+                            public @interface InHtml {
+                            String html();
+                            }
+                            """
+        )
+        myFixture.addClass(
+            """
+                            package myinjection;
+
+                            public @interface InHtmls {
+                            InHtml[] htmls();
+                            }
+                            """
+        )
+        doAnnotationInjectionTest(
+            injectedLanguage = HTMLLanguage.INSTANCE.id,
+            pattern = """psiMethod().withName("html").withParameters().definedInClass("myinjection.InHtml")""",
+            kotlinCode = """
+                                            import myinjection.InHtml
+                                            import myinjection.InHtmls
+
+                                            @InHtmls(htmls = [InHtml(html = "<htm<caret>l></html>")])
+                                            fun foo() {
+                                            }
+                                            """
+        )
+    }
+
     fun testInjectionInAliasedJavaAnnotation() {
         myFixture.addClass("""
                                 @interface InHtml {