Keyword completion: add "class/interface/object + filename" completion for top level (KT-28394)

#KT-28394 Fixed

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/KeywordCompletion.kt

@@ -21,6 +21,7 @@ import com.intellij.codeInsight.completion.InsertionContext
 import com.intellij.codeInsight.lookup.LookupElement
 import com.intellij.codeInsight.lookup.LookupElementBuilder
 import com.intellij.openapi.module.ModuleUtilCore
+import com.intellij.openapi.util.io.FileUtil
 import com.intellij.psi.*
 import com.intellij.psi.filters.*
 import com.intellij.psi.filters.position.LeftNeighbour
@@ -40,8 +41,10 @@ import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.lexer.KtTokens.*
+import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
+import org.jetbrains.kotlin.renderer.render
 import org.jetbrains.kotlin.resolve.ModifierCheckerCore
 import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 
@@ -124,29 +127,47 @@ object KeywordCompletion {
                 consumer(element)
             }
             else {
-                var element = LookupElementBuilder.create(KeywordLookupObject(), keyword).bold()
+                if (listOf(CLASS_KEYWORD, OBJECT_KEYWORD, INTERFACE_KEYWORD).any { keyword.endsWith(it.value) }) {
-
+                    val topLevelClassName = getTopLevelClassName(position)
-                val isUseSiteAnnotationTarget = position.prevLeaf()?.node?.elementType == KtTokens.AT
+                    if (topLevelClassName != null) {
-
+                        consumer(createLookupElementBuilder("$keyword $topLevelClassName", position))
-                val insertHandler = when {
+                    }
-                    isUseSiteAnnotationTarget -> UseSiteAnnotationTargetInsertHandler
-
-                    keyword in NO_SPACE_AFTER -> null
-
-                    else -> SpaceAfterInsertHandler
                 }
-
+                consumer(createLookupElementBuilder(keyword, position))
-                element = element.withInsertHandler(insertHandler)
-
-                if (isUseSiteAnnotationTarget) {
-                    element = element.withPresentableText(keyword + ":")
-                }
-
-                consumer(element)
             }
         }
     }
 
+    private fun createLookupElementBuilder(
+        keyword: String,
+        position: PsiElement
+    ): LookupElementBuilder {
+        val isUseSiteAnnotationTarget = position.prevLeaf()?.node?.elementType == AT
+        val insertHandler = when {
+            isUseSiteAnnotationTarget -> UseSiteAnnotationTargetInsertHandler
+            keyword in NO_SPACE_AFTER -> null
+            else -> SpaceAfterInsertHandler
+        }
+        val element = LookupElementBuilder.create(KeywordLookupObject(), keyword).bold().withInsertHandler(insertHandler)
+        return if (isUseSiteAnnotationTarget) {
+            element.withPresentableText("$keyword:")
+        } else {
+            element
+        }
+    }
+
+    private fun getTopLevelClassName(position: PsiElement): String? {
+        if (position.parents.any { it is KtDeclaration }) return null
+        val file = position.containingFile as? KtFile ?: return null
+        val name = FileUtil.getNameWithoutExtension(file.name)
+        if (!Name.isValidIdentifier(name)
+            || Name.identifier(name).render() != name
+            || !name[0].isUpperCase()
+            || file.declarations.any { it is KtClassOrObject && it.name == name }
+        ) return null
+        return name
+    }
+
     private object UseSiteAnnotationTargetInsertHandler : InsertHandler<LookupElement> {
         override fun handleInsert(context: InsertionContext, item: LookupElement) {
             WithTailInsertHandler(":", spaceBefore = false, spaceAfter = false).postHandleInsert(context, item)

idea/idea-completion/testData/keywords/AfterClasses.kt

@@ -10,6 +10,9 @@ class B {
     }
 }
 
+class AfterClasses {
+}
+
 <caret>
 
 // EXIST:  abstract

idea/idea-completion/testData/keywords/AfterClasses_LangLevel10.kt

@@ -14,24 +14,31 @@ class B {
 
 // EXIST:  abstract
 // EXIST:  class
+// EXIST:  class AfterClasses_LangLevel10
 // EXIST:  enum class
+// EXIST:  enum class AfterClasses_LangLevel10
 // EXIST:  final
 // EXIST:  fun
 // EXIST:  internal
 // EXIST:  object
+// EXIST:  object AfterClasses_LangLevel10
 // EXIST:  open
 // EXIST:  private
 // EXIST:  public
 // EXIST:  interface
+// EXIST:  interface AfterClasses_LangLevel10
 // EXIST:  val
 // EXIST:  var
 // EXIST:  operator
 // EXIST:  infix
 // EXIST:  sealed class
+// EXIST:  sealed class AfterClasses_LangLevel10
 // EXIST:  data class
+// EXIST:  data class AfterClasses_LangLevel10
 // EXIST:  inline
 // EXIST:  tailrec
 // EXIST:  external
 // EXIST:  annotation class
+// EXIST:  annotation class AfterClasses_LangLevel10
 // EXIST:  const val
 // NOTHING_ELSE

idea/idea-completion/testData/keywords/AfterClasses_LangLevel11.kt

@@ -14,25 +14,32 @@ class B {
 
 // EXIST:  abstract
 // EXIST:  class
+// EXIST:  class AfterClasses_LangLevel11
 // EXIST:  enum class
+// EXIST:  enum class AfterClasses_LangLevel11
 // EXIST:  final
 // EXIST:  fun
 // EXIST:  internal
 // EXIST:  object
+// EXIST:  object AfterClasses_LangLevel11
 // EXIST:  open
 // EXIST:  private
 // EXIST:  public
 // EXIST:  interface
+// EXIST:  interface AfterClasses_LangLevel11
 // EXIST:  val
 // EXIST:  var
 // EXIST:  operator
 // EXIST:  infix
 // EXIST:  sealed class
+// EXIST:  sealed class AfterClasses_LangLevel11
 // EXIST:  data class
+// EXIST:  data class AfterClasses_LangLevel11
 // EXIST:  inline
 // EXIST:  tailrec
 // EXIST:  external
 // EXIST:  annotation class
+// EXIST:  annotation class AfterClasses_LangLevel11
 // EXIST:  const val
 // EXIST:  suspend
 // EXIST:  typealias

idea/idea-completion/testData/keywords/GlobalPropertyAccessors.kt

@@ -12,7 +12,9 @@ var a : Int
 // EXIST:  abstract
 // EXIST: by
 // EXIST:  class
+// EXIST:  class GlobalPropertyAccessors
 // EXIST:  enum class
+// EXIST:  enum class GlobalPropertyAccessors
 // EXIST:  final
 // EXIST:  fun
 // EXIST: { itemText: "get", tailText: null }
@@ -20,6 +22,7 @@ var a : Int
 // EXIST: { itemText: "get", tailText: "() {...}" }
 // EXIST:  internal
 // EXIST:  object
+// EXIST:  object GlobalPropertyAccessors
 // EXIST:  open
 // EXIST:  private
 // EXIST:  public
@@ -27,16 +30,20 @@ var a : Int
 // EXIST: { itemText: "set", tailText: "(value) = ..." }
 // EXIST: { itemText: "set", tailText: "(value) {...}" }
 // EXIST:  interface
+// EXIST:  interface GlobalPropertyAccessors
 // EXIST:  val
 // EXIST:  var
 // EXIST:  operator
 // EXIST:  infix
 // EXIST:  sealed class
+// EXIST:  sealed class GlobalPropertyAccessors
 // EXIST:  data class
+// EXIST:  data class GlobalPropertyAccessors
 // EXIST:  inline
 // EXIST:  tailrec
 // EXIST:  external
 // EXIST:  annotation class
+// EXIST:  annotation class GlobalPropertyAccessors
 // EXIST:  const val
 // EXIST:  suspend
 // EXIST:  typealias

idea/idea-completion/testData/keywords/InTopScopeAfterPackage.kt

@@ -4,26 +4,33 @@ package Test
 
 // EXIST:  abstract
 // EXIST:  class
+// EXIST:  class InTopScopeAfterPackage
 // EXIST:  enum class
+// EXIST:  enum class InTopScopeAfterPackage
 // EXIST:  final
 // EXIST:  fun
 // EXIST:  import
 // EXIST:  internal
 // EXIST:  object
+// EXIST:  object InTopScopeAfterPackage
 // EXIST:  open
 // EXIST:  private
 // EXIST:  public
 // EXIST:  interface
+// EXIST:  interface InTopScopeAfterPackage
 // EXIST:  val
 // EXIST:  var
 // EXIST:  operator
 // EXIST:  infix
 // EXIST:  sealed class
+// EXIST:  sealed class InTopScopeAfterPackage
 // EXIST:  data class
+// EXIST:  data class InTopScopeAfterPackage
 // EXIST:  inline
 // EXIST:  tailrec
 // EXIST:  external
 // EXIST:  annotation class
+// EXIST:  annotation class InTopScopeAfterPackage
 // EXIST:  const val
 // EXIST:  suspend
 // EXIST:  typealias

idea/idea-completion/testData/keywords/TopScope.kt

@@ -2,27 +2,34 @@
 
 // EXIST:  abstract
 // EXIST:  class
+// EXIST:  class TopScope
 // EXIST:  enum class
+// EXIST:  enum class TopScope
 // EXIST:  final
 // EXIST:  fun
 // EXIST:  import
 // EXIST:  internal
 // EXIST:  object
+// EXIST:  object TopScope
 // EXIST:  open
 // EXIST:  package
 // EXIST:  private
 // EXIST:  public
 // EXIST:  interface
+// EXIST:  interface TopScope
 // EXIST:  val
 // EXIST:  var
 // EXIST:  operator
 // EXIST:  infix
 // EXIST:  sealed class
+// EXIST:  sealed class TopScope
 // EXIST:  data class
+// EXIST:  data class TopScope
 // EXIST:  inline
 // EXIST:  tailrec
 // EXIST:  external
 // EXIST:  annotation class
+// EXIST:  annotation class TopScope
 // EXIST:  const val
 // EXIST:  suspend
 // EXIST:  typealias

idea/idea-completion/testData/keywords/TopScope3-.kt

@@ -0,0 +1,32 @@
+<caret>
+
+// EXIST:  abstract
+// EXIST:  class
+// EXIST:  enum class
+// EXIST:  final
+// EXIST:  fun
+// EXIST:  import
+// EXIST:  internal
+// EXIST:  object
+// EXIST:  open
+// EXIST:  package
+// EXIST:  private
+// EXIST:  public
+// EXIST:  interface
+// EXIST:  val
+// EXIST:  var
+// EXIST:  operator
+// EXIST:  infix
+// EXIST:  sealed class
+// EXIST:  data class
+// EXIST:  inline
+// EXIST:  tailrec
+// EXIST:  external
+// EXIST:  annotation class
+// EXIST:  const val
+// EXIST:  suspend
+// EXIST:  typealias
+// EXIST:  expect
+// EXIST:  actual
+// EXIST:  lateinit var
+// NOTHING_ELSE

idea/idea-completion/testData/keywords/topScope2.kt

@@ -0,0 +1,32 @@
+<caret>
+
+// EXIST:  abstract
+// EXIST:  class
+// EXIST:  enum class
+// EXIST:  final
+// EXIST:  fun
+// EXIST:  import
+// EXIST:  internal
+// EXIST:  object
+// EXIST:  open
+// EXIST:  package
+// EXIST:  private
+// EXIST:  public
+// EXIST:  interface
+// EXIST:  val
+// EXIST:  var
+// EXIST:  operator
+// EXIST:  infix
+// EXIST:  sealed class
+// EXIST:  data class
+// EXIST:  inline
+// EXIST:  tailrec
+// EXIST:  external
+// EXIST:  annotation class
+// EXIST:  const val
+// EXIST:  suspend
+// EXIST:  typealias
+// EXIST:  expect
+// EXIST:  actual
+// EXIST:  lateinit var
+// NOTHING_ELSE

idea/idea-completion/testData/weighers/basic/TopLevelKeywordWithClassName.kt

@@ -0,0 +1,4 @@
+cla<caret>
+
+// ORDER: class
+// ORDER: class TopLevelKeyword

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/KeywordCompletionTestGenerated.java

@@ -519,6 +519,16 @@ public class KeywordCompletionTestGenerated extends AbstractKeywordCompletionTes
         runTest("idea/idea-completion/testData/keywords/TopScope.kt");
     }
 
+    @TestMetadata("topScope2.kt")
+    public void testTopScope2() throws Exception {
+        runTest("idea/idea-completion/testData/keywords/topScope2.kt");
+    }
+
+    @TestMetadata("TopScope3-.kt")
+    public void testTopScope3_() throws Exception {
+        runTest("idea/idea-completion/testData/keywords/TopScope3-.kt");
+    }
+
     @TestMetadata("UseSiteTargetForPrimaryConstructorParameter.kt")
     public void testUseSiteTargetForPrimaryConstructorParameter() throws Exception {
         runTest("idea/idea-completion/testData/keywords/UseSiteTargetForPrimaryConstructorParameter.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/weighers/BasicCompletionWeigherTestGenerated.java

@@ -204,6 +204,11 @@ public class BasicCompletionWeigherTestGenerated extends AbstractBasicCompletion
         runTest("idea/idea-completion/testData/weighers/basic/SuperMembers.kt");
     }
 
+    @TestMetadata("TopLevelKeywordWithClassName.kt")
+    public void testTopLevelKeywordWithClassName() throws Exception {
+        runTest("idea/idea-completion/testData/weighers/basic/TopLevelKeywordWithClassName.kt");
+    }
+
     @TestMetadata("UnavailableDslReceiver.kt")
     public void testUnavailableDslReceiver() throws Exception {
         runTest("idea/idea-completion/testData/weighers/basic/UnavailableDslReceiver.kt");