Make completion for overriding functions respect suspend modifier

Fixes #KT-22200

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt

@@ -524,12 +524,16 @@ internal class DescriptorRendererImpl(
                 functionDescriptor.isInfix && (functionDescriptor.overriddenDescriptors.none { it.isInfix } || alwaysRenderModifiers)
 
         renderModifier(builder, functionDescriptor.isTailrec, "tailrec")
-        renderModifier(builder, functionDescriptor.isSuspend, "suspend")
+        renderSuspendModifier(functionDescriptor, builder)
         renderModifier(builder, functionDescriptor.isInline, "inline")
         renderModifier(builder, isInfix, "infix")
         renderModifier(builder, isOperator, "operator")
     }
 
+    private fun renderSuspendModifier(functionDescriptor: FunctionDescriptor, builder: StringBuilder) {
+        renderModifier(builder, functionDescriptor.isSuspend, "suspend")
+    }
+
     override fun render(declarationDescriptor: DeclarationDescriptor): String {
         return buildString {
             declarationDescriptor.accept(RenderDeclarationDescriptorVisitor(), this)
@@ -630,6 +634,8 @@ internal class DescriptorRendererImpl(
 
                 if (includeAdditionalModifiers) {
                     renderAdditionalModifiers(function, builder)
+                } else {
+                    renderSuspendModifier(function, builder)
                 }
 
                 renderMemberKind(function, builder)

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

@@ -24,6 +24,7 @@ import com.intellij.icons.AllIcons
 import com.intellij.psi.PsiDocumentManager
 import com.intellij.psi.PsiElement
 import com.intellij.ui.RowIcon
+import org.jetbrains.kotlin.backend.common.descriptors.isSuspend
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.idea.KotlinDescriptorIconProvider
 import org.jetbrains.kotlin.idea.codeInsight.DescriptorToSourceUtilsIde
@@ -43,8 +44,8 @@ import org.jetbrains.kotlin.psi.psiUtil.getNonStrictParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 
 class OverridesCompletion(
-        private val collector: LookupElementsCollector,
+    private val collector: LookupElementsCollector,
-        private val lookupElementFactory: BasicLookupElementFactory
+    private val lookupElementFactory: BasicLookupElementFactory
 ) {
     private val PRESENTATION_RENDERER = IdeDescriptorRenderers.SOURCE_CODE_SHORT_NAMES_IN_TYPES.withOptions {
         modifiers = emptySet()
@@ -85,7 +86,9 @@ class OverridesCompletion(
             val baseClassIcon = KotlinDescriptorIconProvider.getIcon(baseClass, baseClassDeclaration, 0)
 
             lookupElement = object : LookupElementDecorator<LookupElement>(lookupElement) {
-                override fun getLookupString() = if (declaration == null) "override" else delegate.lookupString // don't use "override" as lookup string when already in the name of declaration
+                override fun getLookupString() =
+                    if (declaration == null) "override" else delegate.lookupString // don't use "override" as lookup string when already in the name of declaration
+
                 override fun getAllLookupStrings() = setOf(lookupString, delegate.lookupString)
 
                 override fun renderElement(presentation: LookupElementPresentation) {
@@ -122,6 +125,7 @@ class OverridesCompletion(
                     val prototype = memberObject.generateMember(classOrObject, false)
                     prototype.modifierList!!.replace(modifierList)
                     val insertedMember = dummyMember.replaced(prototype)
+                    if (memberObject.descriptor.isSuspend) insertedMember.addModifier(KtTokens.SUSPEND_KEYWORD)
 
                     ShortenReferences.DEFAULT.process(insertedMember)
 
@@ -135,8 +139,7 @@ class OverridesCompletion(
                         context.document.deleteString(offset, atCharOffset + 1)
 
                         context.editor.moveCaret(offset)
-                    }
+                    } else {
-                    else {
                         moveCaretIntoGeneratedElement(context.editor, insertedMember)
                     }
                 }
@@ -156,8 +159,7 @@ class OverridesCompletion(
                 if (descriptorToOverride !is PropertyDescriptor) return false
                 return if (declaration.valOrVarKeyword?.node?.elementType == KtTokens.VAL_KEYWORD) {
                     !descriptorToOverride.isVar
-                }
+                } else {
-                else {
                     true // var can override either var or val
                 }
             }

idea/idea-completion/testData/basic/common/override/Simple.kt

@@ -5,7 +5,7 @@ interface I {
 }
 
 class Base1 {
-    protected open fun bar(){}
+    protected open suspend fun bar(){}
 }
 
 open class Base2 : Base1() {
@@ -16,7 +16,7 @@ class A : Base2(), I {
 }
 
 // EXIST: { lookupString: "override", itemText: "override" }
-// EXIST: { itemText: "override fun bar() {...}", lookupString: "override", allLookupStrings: "bar, override", tailText: null, typeText: "Base1", attributes: "" }
+// EXIST: { itemText: "override suspend fun bar() {...}", lookupString: "override", allLookupStrings: "bar, override", tailText: null, typeText: "Base1", attributes: "" }
 // EXIST: { itemText: "override fun equals(other: Any?): Boolean {...}", lookupString: "override", allLookupStrings: "equals, override", tailText: null, typeText: "Any", attributes: "" }
 // EXIST: { itemText: "override fun foo(p: Int) {...}", lookupString: "override", allLookupStrings: "foo, override", tailText: null, typeText: "I", attributes: "bold" }
 // EXIST: { itemText: "override fun hashCode(): Int {...}", lookupString: "override", allLookupStrings: "hashCode, override", tailText: null, typeText: "Any", attributes: "" }

idea/idea-completion/testData/handlers/basic/override/Suspend.kt

@@ -0,0 +1,9 @@
+interface I {
+    suspend fun foo()
+}
+
+class A : I {
+    o<caret>
+}
+
+// ELEMENT_TEXT: "override suspend fun foo() {...}"

idea/idea-completion/testData/handlers/basic/override/Suspend.kt.after

@@ -0,0 +1,11 @@
+interface I {
+    suspend fun foo()
+}
+
+class A : I {
+    override suspend fun foo() {
+        <caret><selection>TODO("not implemented") //To change body of created functions use File | Settings | File Templates.</selection>
+    }
+}
+
+// ELEMENT_TEXT: "override suspend fun foo() {...}"

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/handlers/BasicCompletionHandlerTestGenerated.java

@@ -582,6 +582,12 @@ public class BasicCompletionHandlerTestGenerated extends AbstractBasicCompletion
             doTest(fileName);
         }
 
+        @TestMetadata("Suspend.kt")
+        public void testSuspend() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/handlers/basic/override/Suspend.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("TypeFunctionName.kt")
         public void testTypeFunctionName() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/handlers/basic/override/TypeFunctionName.kt");