Fix navigation in IDE to synthetic methods in compiled Kotlin

For some synthetic methods from compiled Kotlin classes, it is
not possible to find the PsiElement, when navigating to declaration
in the IDE.

For other methods it works like this:
1. There is a SourceElement with a psi inside
2. Or for K1, the element is searched in the decompiled text
   (see ByDescriptorIndexer),
3. Or for K2, the element is searched by Stub taken from metadata
   (see FirDeserializedDeclarationSourceProvider)

However, these approaches do not apply to synthetic methods which have
no SourceElement and are not written into decompiled text and metadata.

These are methods values, valueOf, entries from enum and
copy, equals, hashCode, toString from data classes.

Therefore, it was decided to handle their cases separately
at the resolve stage.

Tests (in idea repository):
- org.jetbrains.kotlin.idea.resolve.ReferenceResolveWithLibTestGenerated#testDataClassSyntheticMethods
- org.jetbrains.kotlin.idea.resolve.ReferenceResolveWithLibTestGenerated#testEnumSyntheticMethods
- org.jetbrains.kotlin.idea.fir.resolve.FirReferenceResolveWithLibTestGenerated#testDataClassSyntheticMethods
- org.jetbrains.kotlin.idea.fir.resolve.FirReferenceResolveWithLibTestGenerated#testEnumSyntheticMethods

^KTIJ-24413 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/FirDeserializedDeclarationSourceProvider.kt

@@ -12,10 +12,15 @@ import org.jetbrains.kotlin.analysis.low.level.api.fir.api.KtDeclarationAndFirDe
 import org.jetbrains.kotlin.analysis.low.level.api.fir.project.structure.llFirModuleData
 import org.jetbrains.kotlin.analysis.project.structure.KtBuiltinsModule
 import org.jetbrains.kotlin.analysis.providers.createDeclarationProvider
+import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.containingClassLookupTag
 import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.utils.isData
+import org.jetbrains.kotlin.fir.declarations.utils.isEnumClass
+import org.jetbrains.kotlin.fir.resolve.getContainingClass
 import org.jetbrains.kotlin.fir.scopes.impl.delegatedWrapperData
+import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.unwrapFakeOverrides
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
@@ -25,6 +30,7 @@ import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.KtFunction
 import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.util.OperatorNameConventions
 
 //todo introduce LibraryModificationTracker based cache?
 internal object FirDeserializedDeclarationSourceProvider {
@@ -40,6 +46,34 @@ internal object FirDeserializedDeclarationSourceProvider {
         }
     }
 
+    fun findClassPsiForGeneratedMembers(fir: FirElement, project: Project): PsiElement? {
+        if (fir !is FirCallableDeclaration) {
+            return null
+        }
+        val containingClass = fir.getContainingClass(fir.moduleData.session) ?: return null
+        if (isGeneratedMemberNotWrittenToMetadata(fir.symbol, containingClass)) {
+            return provideSourceForClass(containingClass, project)
+        }
+        return null
+    }
+
+    private fun isGeneratedMemberNotWrittenToMetadata(symbol: FirCallableSymbol<*>, containingClass: FirRegularClass): Boolean {
+        return when {
+            containingClass.isEnumClass -> symbol.name in setOf(
+                StandardNames.ENUM_VALUES,
+                StandardNames.ENUM_VALUE_OF,
+                StandardNames.ENUM_ENTRIES,
+            )
+            containingClass.isData -> symbol.name in setOf(
+                OperatorNameConventions.EQUALS,
+                OperatorNameConventions.TO_STRING,
+                StandardNames.HASHCODE_NAME,
+                StandardNames.DATA_CLASS_COPY,
+            )
+            else -> false
+        }
+    }
+
     private fun provideSourceForFunction(
         function: FirSimpleFunction,
         project: Project

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/psiUtils.kt

@@ -51,6 +51,9 @@ fun FirElement.findPsi(session: FirSession): PsiElement? =
  * For data classes & enums generated members like `copy` `componentN`, `values` it will return corresponding enum/data class
  * Otherwise, behaves the same way as [findPsi] returns exact PSI declaration corresponding to passed [FirDeclaration]
  */
-fun FirDeclaration.findReferencePsi(): PsiElement? =
-    psi
-        ?: FirDeserializedDeclarationSourceProvider.findPsi(this, (moduleData.session as LLFirSession).project)
+fun FirDeclaration.findReferencePsi(): PsiElement? {
+    psi?.let { return it }
+    val project = (moduleData.session as LLFirSession).project
+    return FirDeserializedDeclarationSourceProvider.findPsi(this, project)
+        ?: FirDeserializedDeclarationSourceProvider.findClassPsiForGeneratedMembers(this, project)
+}

analysis/decompiled/decompiler-to-psi/src/org/jetbrains/kotlin/analysis/decompiler/psi/text/ByDescriptorIndexer.kt

@@ -52,6 +52,12 @@ object ByDescriptorIndexer : DecompiledTextIndexer<String> {
             return classOrObject?.primaryConstructor ?: classOrObject
         }
 
+        if ((original as? CallableMemberDescriptor)?.mustNotBeWrittenToDecompiledText() == true &&
+            original.containingDeclaration is ClassDescriptor
+        ) {
+            return getDeclarationForDescriptor(original.containingDeclaration, file)
+        }
+
         val descriptorKey = original.toStringKey()
 
         if (!file.isContentsLoaded && original is MemberDescriptor) {

analysis/decompiled/decompiler-to-psi/src/org/jetbrains/kotlin/analysis/decompiler/psi/text/buildDecompiledText.kt

@@ -34,6 +34,20 @@ fun DescriptorRendererOptions.defaultDecompilerRendererOptions() {
     parameterNamesInFunctionalTypes = false // to support parameters names in decompiled text we need to load annotation arguments
 }
 
+internal fun CallableMemberDescriptor.mustNotBeWrittenToDecompiledText(): Boolean {
+    return when (kind) {
+        CallableMemberDescriptor.Kind.DECLARATION -> false
+
+        CallableMemberDescriptor.Kind.FAKE_OVERRIDE,
+        CallableMemberDescriptor.Kind.DELEGATION -> true
+
+        CallableMemberDescriptor.Kind.SYNTHESIZED -> {
+            // Of all synthesized functions, only `component*` functions are rendered (for historical reasons)
+            !DataClassDescriptorResolver.isComponentLike(name)
+        }
+    }
+}
+
 fun buildDecompiledText(
     packageFqName: FqName,
     descriptors: List<DeclarationDescriptor>,
@@ -56,20 +70,6 @@ fun buildDecompiledText(
         textIndex.addToIndex(descriptor, TextRange(startOffset, endOffset))
     }
 
-    fun CallableMemberDescriptor.isConsideredSynthetic(): Boolean {
-        return when (kind) {
-            CallableMemberDescriptor.Kind.DECLARATION -> false
-
-            CallableMemberDescriptor.Kind.FAKE_OVERRIDE,
-            CallableMemberDescriptor.Kind.DELEGATION -> true
-
-            CallableMemberDescriptor.Kind.SYNTHESIZED -> {
-                // Of all synthesized functions, only `component*` functions are rendered (for historical reasons)
-                !DataClassDescriptorResolver.isComponentLike(name)
-            }
-        }
-    }
-
     fun appendDescriptor(descriptor: DeclarationDescriptor, indent: String, lastEnumEntry: Boolean? = null) {
         val startOffset = builder.length
         if (isEnumEntry(descriptor)) {
@@ -144,7 +144,7 @@ fun buildDecompiledText(
                 if (member == companionObject) {
                     continue
                 }
-                if (member is CallableMemberDescriptor && member.isConsideredSynthetic()) {
+                if (member is CallableMemberDescriptor && member.mustNotBeWrittenToDecompiledText()) {
                     continue
                 }
                 newlineExceptFirst()