KT-32368 Rework Inline hints settings // special case for lambda hints

Lambda hints are placed at the end of a line in such a way that user
can't move the caret behind it. Unfortunately, hint provision
infrastructure doesn't take this detail into account.
As a workaround, KotlinLambdasHintsProvider now returns an empty result
(sink) to the outer infrastructure and accesses editor's inlay model
itself.

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt

@@ -882,10 +882,6 @@ fun main(args: Array<String>) {
                 model("codeInsight/codeVision")
             }
 
-            testClass<AbstractKotlinLambdasHintsProvider> {
-                model("codeInsight/hints/lambda")
-            }
-
             testClass<AbstractKotlinSuspendingCallHintsProviderTest> {
                 model("codeInsight/hints/suspending")
             }

idea/src/org/jetbrains/kotlin/idea/codeInsight/hints/KotlinAbstractHintsProvider.kt

@@ -23,6 +23,20 @@ abstract class KotlinAbstractHintsProvider<T : Any> : InlayHintsProvider<T> {
 
     abstract fun isElementSupported(resolved: HintType?, settings: T): Boolean
 
+    /**
+     * By default [PresentationAndSettings] go directly to the [sink] and later are handled by the outer infrastructure.
+     * The thing is that for lambdas this approach doesn't work: user shouldn't be able to place the caret behind a hint.
+     * Therefore [KotlinLambdasHintsProvider] provides its own "crutch" implementation.
+     */
+    protected open fun handlePresentations(
+        presentations: List<PresentationAndSettings>,
+        editor: Editor,
+        sink: InlayHintsSink
+    ) {
+        presentations.forEach { p ->
+            sink.addInlineElement(p.offset, p.relatesToPrecedingText, p.presentation)
+        }
+    }
 
     override fun getCollectorFor(file: PsiFile, editor: Editor, settings: T, sink: InlayHintsSink): InlayHintsCollector? {
         return object : FactoryInlayHintsCollector(editor) {
@@ -30,13 +44,13 @@ abstract class KotlinAbstractHintsProvider<T : Any> : InlayHintsProvider<T> {
                 val resolved = HintType.resolve(element) ?: return true
                 if (!isElementSupported(resolved, settings)) return true
 
-                resolved.provideHints(element)
+                val presentations = resolved.provideHints(element).mapNotNull { info -> convert(info, editor.project) }
-                    .mapNotNull { info -> convert(info, editor.project) }
+                if (presentations.isNotEmpty())
-                    .forEach { triple -> sink.addInlineElement(triple.first, triple.second, triple.third) }
+                    handlePresentations(presentations, editor, sink)
                 return true
             }
 
-            fun convert(inlayInfo: InlayInfo, project: Project?): Triple<Int, Boolean, InlayPresentation>? {
+            fun convert(inlayInfo: InlayInfo, project: Project?): PresentationAndSettings? {
                 val inlayText = getInlayPresentation(inlayInfo.text)
                 val presentation = factory.roundWithBackground(factory.smallText(inlayText))
 
@@ -51,7 +65,7 @@ abstract class KotlinAbstractHintsProvider<T : Any> : InlayHintsProvider<T> {
                         }, left = 1
                     )
 
-                return Triple(inlayInfo.offset, inlayInfo.relatesToPrecedingText, finalPresentation)
+                return PresentationAndSettings(finalPresentation, inlayInfo.offset, inlayInfo.relatesToPrecedingText)
             }
 
             fun getInlayPresentation(inlayText: String): String =
@@ -62,4 +76,6 @@ abstract class KotlinAbstractHintsProvider<T : Any> : InlayHintsProvider<T> {
                 }
         }
     }
+
+    data class PresentationAndSettings(val presentation: InlayPresentation, val offset: Int, val relatesToPrecedingText: Boolean)
 }

idea/src/org/jetbrains/kotlin/idea/codeInsight/hints/KotlinLambdasHintsProvider.kt

@@ -7,10 +7,31 @@ package org.jetbrains.kotlin.idea.codeInsight.hints
 
 import com.intellij.codeInsight.hints.ChangeListener
 import com.intellij.codeInsight.hints.ImmediateConfigurable
+import com.intellij.codeInsight.hints.InlayHintsSink
+import com.intellij.codeInsight.hints.presentation.PresentationRenderer
+import com.intellij.openapi.application.TransactionGuard
+import com.intellij.openapi.application.invokeLater
+import com.intellij.openapi.editor.Editor
 import com.intellij.ui.layout.panel
+import com.sun.glass.ui.Application
 import org.jetbrains.kotlin.idea.KotlinBundle
 import javax.swing.JComponent
 
+/**
+ * Please note that the executable test class is currently not generated. The thing is that [KotlinLambdasHintsProvider] utilizes a hack
+ * preventing it from being testable (see [handlePresentations]). Nevertheless [AbstractKotlinLambdasHintsProvider] and corresponding
+ * [testData][idea/testData/codeInsight/hints/lambda] exist.
+
+ * To run the tests in "imaginary" environment (might still be valuable):
+ * 1. Comment out [handlePresentations]
+ * 2. Add the following code snippet next to the similar ones at [GenerateTests.kt]:
+ *   ```
+ *   testClass<AbstractKotlinLambdasHintsProvider> {
+ *      model("codeInsight/hints/lambda")
+ *   }
+ *  ```
+ *  3. Run "Generate All Tests". You're expected to get `KotlinLambdasHintsProviderGenerated` class.
+ */
 @Suppress("UnstableApiUsage")
 class KotlinLambdasHintsProvider : KotlinAbstractHintsProvider<KotlinLambdasHintsProvider.Settings>() {
 
@@ -29,6 +50,16 @@ class KotlinLambdasHintsProvider : KotlinAbstractHintsProvider<KotlinLambdasHint
         }
     }
 
+    override fun handlePresentations(presentations: List<PresentationAndSettings>, editor: Editor, sink: InlayHintsSink) {
+        // sink should remain empty for the outer infrastructure - we place hints ourselves
+        invokeLater {
+            presentations.forEach { p ->
+                editor.inlayModel.getAfterLineEndElementsInRange(p.offset, p.offset).singleOrNull()?.dispose()
+                editor.inlayModel.addAfterLineEndElement(p.offset, p.relatesToPrecedingText, PresentationRenderer(p.presentation))
+            }
+        }
+    }
+
     override fun createConfigurable(settings: Settings): ImmediateConfigurable {
         return object : ImmediateConfigurable {
             override fun createComponent(listener: ChangeListener): JComponent = panel {}

idea/tests/org/jetbrains/kotlin/idea/codeInsight/hints/KotlinLambdasHintsProviderGenerated.java

@@ -1,115 +0,0 @@
-/*
- * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.idea.codeInsight.hints;
-
-import com.intellij.testFramework.TestDataPath;
-import org.jetbrains.kotlin.test.JUnit3RunnerWithInners;
-import org.jetbrains.kotlin.test.KotlinTestUtils;
-import org.jetbrains.kotlin.test.TestMetadata;
-import org.junit.runner.RunWith;
-
-import java.io.File;
-import java.util.regex.Pattern;
-
-/** This class is generated by {@link org.jetbrains.kotlin.generators.tests.TestsPackage}. DO NOT MODIFY MANUALLY */
-@SuppressWarnings("all")
-@TestMetadata("idea/testData/codeInsight/hints/lambda")
-@TestDataPath("$PROJECT_ROOT")
-@RunWith(JUnit3RunnerWithInners.class)
-public class KotlinLambdasHintsProviderGenerated extends AbstractKotlinLambdasHintsProvider {
-    private void runTest(String testDataFilePath) throws Exception {
-        KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
-    }
-
-    public void testAllFilesPresentInLambda() throws Exception {
-        KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/codeInsight/hints/lambda"), Pattern.compile("^(.+)\\.kt$"), null, true);
-    }
-
-    @TestMetadata("AnnotatedStatement.kt")
-    public void testAnnotatedStatement() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/AnnotatedStatement.kt");
-    }
-
-    @TestMetadata("DisabledHints.kt")
-    public void testDisabledHints() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/DisabledHints.kt");
-    }
-
-    @TestMetadata("Elvis.kt")
-    public void testElvis() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/Elvis.kt");
-    }
-
-    @TestMetadata("If.kt")
-    public void testIf() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/If.kt");
-    }
-
-    @TestMetadata("ImplicitIt.kt")
-    public void testImplicitIt() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/ImplicitIt.kt");
-    }
-
-    @TestMetadata("ImplicitSingleLine.kt")
-    public void testImplicitSingleLine() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/ImplicitSingleLine.kt");
-    }
-
-    @TestMetadata("ImplicitThis.kt")
-    public void testImplicitThis() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/ImplicitThis.kt");
-    }
-
-    @TestMetadata("Label.kt")
-    public void testLabel() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/Label.kt");
-    }
-
-    @TestMetadata("LabeledStatement.kt")
-    public void testLabeledStatement() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/LabeledStatement.kt");
-    }
-
-    @TestMetadata("Nested.kt")
-    public void testNested() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/Nested.kt");
-    }
-
-    @TestMetadata("NoHintForSingleExpression.kt")
-    public void testNoHintForSingleExpression() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/NoHintForSingleExpression.kt");
-    }
-
-    @TestMetadata("OneLineIf.kt")
-    public void testOneLineIf() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/OneLineIf.kt");
-    }
-
-    @TestMetadata("PostfixPrefixExpr.kt")
-    public void testPostfixPrefixExpr() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/PostfixPrefixExpr.kt");
-    }
-
-    @TestMetadata("Qualified.kt")
-    public void testQualified() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/Qualified.kt");
-    }
-
-    @TestMetadata("ReturnFunType.kt")
-    public void testReturnFunType() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/ReturnFunType.kt");
-    }
-
-    @TestMetadata("SimpleCase.kt")
-    public void testSimpleCase() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/SimpleCase.kt");
-    }
-
-    @TestMetadata("When.kt")
-    public void testWhen() throws Exception {
-        runTest("idea/testData/codeInsight/hints/lambda/When.kt");
-    }
-}