Fix: Unstable IDE navigation to expect/actual symbols in stdlib

Issue #KT-30790 Fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/navigation/SourceNavigationHelper.kt

@@ -35,7 +35,6 @@ import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.debugText.getDebugText
-import org.jetbrains.kotlin.resolve.TargetPlatform
 import org.jetbrains.kotlin.utils.addToStdlib.firstNotNullResult
 
 object SourceNavigationHelper {
@@ -191,8 +190,8 @@ object SourceNavigationHelper {
         index: StringStubIndexExtension<T>
     ): T? {
         val classFqName = entity.fqName ?: return null
-        return targetScopes(entity, navigationKind).firstNotNullResult {
+        return targetScopes(entity, navigationKind).firstNotNullResult { scope ->
-            index.get(classFqName.asString(), entity.project, it).firstOrNull()
+            index.get(classFqName.asString(), entity.project, scope).sortedBy { it.isExpectDeclaration() }.firstOrNull()
         }
     }
 

idea/tests/org/jetbrains/kotlin/idea/decompiler/navigation/LightNavigateToStdlibSourceTest.kt

@@ -5,9 +5,14 @@
 
 package org.jetbrains.kotlin.idea.decompiler.navigation
 
+import com.intellij.psi.PsiElement
 import junit.framework.TestCase
 import org.jetbrains.kotlin.idea.KotlinFileType
 import org.jetbrains.kotlin.idea.test.*
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtModifierListOwner
+import org.jetbrains.kotlin.psi.KtTypeAlias
+import org.jetbrains.kotlin.psi.psiUtil.hasActualModifier
 
 class LightNavigateToStdlibSourceTest : KotlinLightCodeInsightFixtureTestCase() {
     @ProjectDescriptorKind(JDK_AND_MULTIPLATFORM_STDLIB_WITH_SOURCES)
@@ -26,6 +31,35 @@ class LightNavigateToStdlibSourceTest : KotlinLightCodeInsightFixtureTestCase()
         )
     }
 
+    @ProjectDescriptorKind(KOTLIN_JVM_WITH_STDLIB_SOURCES)
+    fun testNavigateToJVMActualClassDeclarations() {
+        val checkedTypes = listOf(
+            // abstract actual classes in JVM:
+            "AbstractMutableCollection<String>",
+            "AbstractMutableList<String>",
+            "AbstractMutableSet<String>",
+            "AbstractMutableMap<String, String>",
+
+            // actual typealiases in JVM:
+            "ArrayList<String>",
+            "HashSet<String>"
+        )
+
+        for (type in checkedTypes) {
+            doTest("fun some() { val collection: <caret>$type? = null }") { navigationElement ->
+                TestCase.assertTrue(
+                    "$navigationElement is not instance of ${KtClassOrObject::class} or ${KtTypeAlias::class}",
+                    navigationElement is KtClassOrObject || navigationElement is KtTypeAlias
+                )
+
+                TestCase.assertTrue(
+                    "$navigationElement is not actual declaration",
+                    (navigationElement as KtModifierListOwner).hasActualModifier()
+                )
+            }
+        }
+    }
+
     @ProjectDescriptorKind(KOTLIN_JVM_WITH_STDLIB_SOURCES)
     fun testRefToPrintlnWithJVM() {
         doTest(
@@ -57,13 +91,19 @@ class LightNavigateToStdlibSourceTest : KotlinLightCodeInsightFixtureTestCase()
 
     override fun getProjectDescriptor() = getProjectDescriptorFromAnnotation()
 
-    private fun doTest(text: String, sourceFileName: String) {
+    private fun doTest(text: String, sourceFileName: String) = doTest(text) { navigationElement ->
+        // by default check by source file name
+        TestCase.assertEquals(sourceFileName, navigationElement.containingFile.name)
+    }
+
+    private fun doTest(text: String, checker: (PsiElement) -> Unit) {
         myFixture.configureByText(KotlinFileType.INSTANCE, text)
 
         val ref = file.findReferenceAt(editor.caretModel.offset)
         val resolve = ref!!.resolve()
         val navigationElement = resolve!!.navigationElement
 
-        TestCase.assertEquals(sourceFileName, navigationElement.containingFile.name)
+        checker(navigationElement)
     }
-}
+}
+