[kotlin] KTIJ-35779 Fix Implement members when body has no braces

GitOrigin-RevId: bc8a0d005478d6bbdc86936718251ec2abe7473f

plugins/kotlin/code-insight/impl-base/src/org/jetbrains/kotlin/idea/core/generateUtils.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.psi.psiUtil.allChildren
 import org.jetbrains.kotlin.psi.psiUtil.endOffset
 import org.jetbrains.kotlin.psi.psiUtil.siblings
 import org.jetbrains.kotlin.psi.psiUtil.startOffset
+import org.jetbrains.kotlin.utils.KotlinExceptionWithAttachments
 import kotlin.math.min
 
 fun moveCaretIntoGeneratedElement(editor: Editor, element: PsiElement) {
@@ -222,11 +223,13 @@ fun <T : KtDeclaration> insertMembersAfter(
                     commentOrSpace.copy().also { commentOrSpace.delete() }
                 }
             }
-        val body = classOrObject.getOrCreateBody()
-        val lBrace = body.lBrace
-        if (lBrace != null) {
-            tailComments.reversed().map { body.addAfter(it, lBrace) }
+        val existedBody = classOrObject.body
+        val body = existedBody?.takeIf { it.lBrace != null } ?: run {
+            existedBody?.delete()
+            classOrObject.getOrCreateBody()
         }
+        val lBrace = body.lBrace ?: throw KotlinExceptionWithAttachments("no lBrace").withPsiAttachment("classOrObject", classOrObject)
+        tailComments.reversed().forEach { body.addAfter(it, lBrace) }
 
         var afterAnchor = anchor ?: findInsertAfterAnchor(editor, body) ?: return emptyList()
         otherMembers.mapTo(insertedMembers) {
@@ -242,7 +245,7 @@ fun <T : KtDeclaration> insertMembersAfter(
                         afterAnchor = bound
                     }
                 } else if (bound == null && body.declarations.isNotEmpty()) {
-                    afterAnchor = body.lBrace!!
+                    afterAnchor = lBrace
                 } else if (bound != null && afterAnchor.startOffset > bound.startOffset) {
                     afterAnchor = bound.prevSibling!!
                 }

plugins/kotlin/code-insight/override-implement-k2/src/org/jetbrains/kotlin/idea/core/overrideImplement/KtGenerateMembersHandler.kt

@@ -182,7 +182,7 @@ abstract class KtGenerateMembersHandler(
      * implementation for the chosen symbol.
      */
     context(_: KaSession)
-private fun getMembersOrderedByRelativePositionsInSuperTypes(
+    private fun getMembersOrderedByRelativePositionsInSuperTypes(
         currentClass: KtClassOrObject,
         newMemberSymbolsAndGeneratedPsi: Map<KaCallableSymbol, KtCallableDeclaration>
     ): List<MemberEntry> {

plugins/kotlin/fir/tests/test/org/jetbrains/kotlin/idea/fir/codeInsight/FirOverrideImplementTest.kt

@@ -144,6 +144,10 @@ internal class FirOverrideImplementTest : OverrideImplementTest<KtClassMember>()
         super.testOverrideFunctionProperty()
     }
 
+    override fun testOverrideFunctionPropertyWithoutBody() {
+        super.testOverrideFunctionPropertyWithoutBody()
+    }
+
     override fun testOverridePrimitiveProperty() {
         super.testOverridePrimitiveProperty()
     }

plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/codeInsight/OverrideImplementTest.kt

@@ -133,6 +133,10 @@ abstract class OverrideImplementTest<T : ClassMember> : AbstractOverrideImplemen
         doOverrideFileTest()
     }
 
+    open fun testOverrideFunctionPropertyWithoutBody() {
+        doOverrideFileTest()
+    }
+
     open fun testOverridePrimitiveProperty() {
         doMultiImplementFileTest()
     }

plugins/kotlin/idea/tests/testData/codeInsight/overrideImplement/overrideFunctionPropertyWithoutBody.kt

@@ -0,0 +1,15 @@
+// FIR_IDENTICAL
+open class A() {
+    open val method : () -> Unit? = {println("hello")}
+}
+
+fun some() : A {
+    return object : A()<caret>
+}
+
+// TODO: need better selection and caret
+
+// MEMBER: "method: () -> Unit?"
+// MEMBER: "equals(other: Any?): Boolean"
+// MEMBER: "hashCode(): Int"
+// MEMBER: "toString(): String"

plugins/kotlin/idea/tests/testData/codeInsight/overrideImplement/overrideFunctionPropertyWithoutBody.kt.after

@@ -0,0 +1,18 @@
+// FIR_IDENTICAL
+open class A() {
+    open val method : () -> Unit? = {println("hello")}
+}
+
+fun some() : A {
+    return object : A() {
+        override val method: () -> Unit?
+            get() = <selection><caret>super.method</selection>
+    }
+}
+
+// TODO: need better selection and caret
+
+// MEMBER: "method: () -> Unit?"
+// MEMBER: "equals(other: Any?): Boolean"
+// MEMBER: "hashCode(): Int"
+// MEMBER: "toString(): String"