Conversion to Kotlin on paste: supported for annotation

idea/src/org/jetbrains/kotlin/idea/conversion/copy/DataForConversion.kt

@@ -22,6 +22,7 @@ import com.intellij.openapi.util.TextRange
 import com.intellij.psi.*
 import org.jetbrains.kotlin.name.FqNameUnsafe
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMap
+import org.jetbrains.kotlin.psi.psiUtil.allChildren
 import org.jetbrains.kotlin.psi.psiUtil.elementsInRange
 import org.jetbrains.kotlin.psi.psiUtil.parents
 import org.jetbrains.kotlin.psi.psiUtil.siblings
@@ -217,11 +218,16 @@ data class DataForConversion private(
             }
             else {
                 add(fileText.substring(range.start, elements.first().range.start))
-                addAll(elements)
+                elements.flatMapTo(this) {
+                    if (shouldExpandToChildren(it)) it.allChildren.toList() else listOf(it)
+                }
                 add(fileText.substring(elements.last().range.end, range.end))
             }
         }
 
+        // converting of PsiModifierList is not supported by converter, but converting of single annotations inside it is supported
+        private fun shouldExpandToChildren(element: PsiElement) = element is PsiModifierList
+
         private fun buildImportsAndPackage(sourceFile: PsiJavaFile): String {
             return StringBuilder {
                 val packageName = sourceFile.getPackageName()

idea/testData/copyPaste/conversion/CopyAnnotation.expected.kt

@@ -0,0 +1,2 @@
+Ann(String::class)
+class X

idea/testData/copyPaste/conversion/CopyAnnotation.java

@@ -0,0 +1,7 @@
+@interface Ann {
+    Class value();
+}
+
+<selection>@Ann(String.class)
+</selection>class C {
+}

idea/testData/copyPaste/conversion/CopyAnnotation.to.kt

@@ -0,0 +1 @@
+<caret>class X

idea/tests/org/jetbrains/kotlin/idea/conversion/copy/JavaToKotlinCopyPasteConversionTestGenerated.java

@@ -95,6 +95,12 @@ public class JavaToKotlinCopyPasteConversionTestGenerated extends AbstractJavaTo
         doTest(fileName);
     }
 
+    @TestMetadata("CopyAnnotation.java")
+    public void testCopyAnnotation() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/testData/copyPaste/conversion/CopyAnnotation.java");
+        doTest(fileName);
+    }
+
     @TestMetadata("FieldWithNoEndComment.java")
     public void testFieldWithNoEndComment() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("idea/testData/copyPaste/conversion/FieldWithNoEndComment.java");