Fix for KT-7995 Quick doc should show deprecation info and ReplaceWith

compiler/frontend/src/org/jetbrains/kotlin/resolve/deprecationUtil.kt

@@ -36,13 +36,21 @@ private val JAVA_DEPRECATED = FqName("java.lang.Deprecated")
 
 interface Deprecation {
     val deprecationLevel: DeprecationLevelValue
-    val message: String
+    val message: String?
     val target: DeclarationDescriptor
 }
 
 fun Deprecation.deprecatedByOverriddenMessage(): String? = (this as? DeprecatedByOverridden)?.additionalMessage()
 
-private data class DeprecatedByAnnotation(private val annotation: AnnotationDescriptor, override val target: DeclarationDescriptor) : Deprecation {
+fun Deprecation.deprecatedByAnnotationReplaceWithExpression(): String? {
+    val annotation = (this as? DeprecatedByAnnotation)?.annotation ?: return null
+    val replaceWithAnnotation = annotation.argumentValue(kotlin.Deprecated::replaceWith.name)
+                                        as? AnnotationDescriptor ?: return null
+
+    return replaceWithAnnotation.argumentValue(kotlin.ReplaceWith::expression.name) as String
+}
+
+private data class DeprecatedByAnnotation(val annotation: AnnotationDescriptor, override val target: DeclarationDescriptor) : Deprecation {
     override val deprecationLevel: DeprecationLevelValue
         get() {
             val level = annotation.argumentValue("level") as? ClassDescriptor
@@ -55,8 +63,8 @@ private data class DeprecatedByAnnotation(private val annotation: AnnotationDesc
             }
         }
 
-    override val message: String
-        get() = annotation.argumentValue("message") as? String ?: ""
+    override val message: String?
+        get() = annotation.argumentValue("message") as? String
 }
 
 private data class DeprecatedByOverridden(private val deprecations: Collection<Deprecation>) : Deprecation {
@@ -184,7 +192,7 @@ internal fun createDeprecationDiagnostic(element: PsiElement, deprecation: Depre
         ERROR -> Errors.DEPRECATION_ERROR
         HIDDEN -> Errors.DEPRECATION_ERROR
     }
-    return diagnosticFactory.on(element, targetOriginal, deprecation.message)
+    return diagnosticFactory.on(element, targetOriginal, deprecation.message ?: "")
 }
 
 // values from kotlin.DeprecationLevel

idea/src/org/jetbrains/kotlin/idea/KotlinQuickDocumentationProvider.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.idea
 
+import com.google.common.html.HtmlEscapers
 import com.intellij.codeInsight.documentation.DocumentationManagerUtil
 import com.intellij.lang.documentation.AbstractDocumentationProvider
 import com.intellij.lang.java.JavaDocumentationProvider
@@ -41,7 +42,9 @@ import org.jetbrains.kotlin.psi.psiUtil.getNonStrictParentOfType
 import org.jetbrains.kotlin.renderer.ClassifierNamePolicy
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.deprecatedByAnnotationReplaceWithExpression
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
+import org.jetbrains.kotlin.resolve.getDeprecation
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 import org.jetbrains.kotlin.utils.addToStdlib.constant
 
@@ -153,6 +156,9 @@ class KotlinQuickDocumentationProvider : AbstractDocumentationProvider() {
             if (!quickNavigation) {
                 renderedDecl = "<pre>$renderedDecl</pre>"
             }
+
+            renderedDecl += renderDeprecationInfo(declarationDescriptor)
+
             val comment = declarationDescriptor.findKDoc()
             if (comment != null) {
                 val renderedComment = KDocRenderer.renderKDoc(comment)
@@ -167,6 +173,39 @@ class KotlinQuickDocumentationProvider : AbstractDocumentationProvider() {
             return renderedDecl
         }
 
+        private fun renderDeprecationInfo(declarationDescriptor: DeclarationDescriptor): String {
+            val deprecation = declarationDescriptor.getDeprecation() ?: return ""
+
+            return buildString {
+                wrapTag("DL") {
+                    deprecation.message?.let { message ->
+                        wrapTag("DT") { wrapTag("b") { append("Deprecated:") } }
+                        wrapTag("DD") {
+                            append(message.htmlEscape())
+                        }
+                    }
+                    deprecation.deprecatedByAnnotationReplaceWithExpression()?.let { replaceWith ->
+                        wrapTag("DT") { wrapTag("b") { append("Replace with:") } }
+                        wrapTag("DD") {
+                            wrapTag("code") { append(replaceWith.htmlEscape()) }
+                        }
+                    }
+                }
+            }
+        }
+
+        fun String.htmlEscape(): String = HtmlEscapers.htmlEscaper().escape(this)
+
+        private inline fun StringBuilder.wrap(prefix: String, postfix: String, crossinline body: () -> Unit) {
+            this.append(prefix)
+            body()
+            this.append(postfix)
+        }
+
+        private inline fun StringBuilder.wrapTag(tag: String, crossinline body: () -> Unit) {
+            wrap("<$tag>", "</$tag>", body)
+        }
+
         private fun mixKotlinToJava(declarationDescriptor: DeclarationDescriptor, element: PsiElement, originalElement: PsiElement?): String? {
             val originalInfo = JavaDocumentationProvider().getQuickNavigateInfo(element, originalElement)
             if (originalInfo != null) {

idea/testData/editor/quickDoc/DeprecationWithReplaceInfo.kt

@@ -0,0 +1,6 @@
+@Deprecated("lol no more mainstream", replaceWith = ReplaceWith(expression = "kek()"))
+fun <caret>lol() {
+    println("lol")
+}
+
+//INFO: @<a href="psi_element://kotlin.Deprecated">Deprecated</a> <b>public</b> <b>fun</b> lol(): Unit <i>defined in</i> root package<DL><DT><b>Deprecated:</b></DT><DD>lol no more mainstream</DD><DT><b>Replace with:</b></DT><DD><code>kek()</code></DD></DL>

idea/tests/org/jetbrains/kotlin/idea/editor/quickDoc/QuickDocProviderTestGenerated.java

@@ -72,6 +72,12 @@ public class QuickDocProviderTestGenerated extends AbstractQuickDocProviderTest
         doTest(fileName);
     }
 
+    @TestMetadata("DeprecationWithReplaceInfo.kt")
+    public void testDeprecationWithReplaceInfo() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/quickDoc/DeprecationWithReplaceInfo.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("EscapeHtmlInsideCodeBlocks.kt")
     public void testEscapeHtmlInsideCodeBlocks() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/quickDoc/EscapeHtmlInsideCodeBlocks.kt");