Fix Show implementation to show inheritance through type-aliases

Show implementation(Ctrl-Hover) now should show classes which inherit such class through type-alias
 #KT-15200 fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/TargetPlatformDetector.java

@@ -51,10 +51,16 @@ public class TargetPlatformDetector {
             return contextFile instanceof KtFile ? getPlatform((KtFile) contextFile) : JvmPlatform.INSTANCE;
         }
 
+        return getPlatform((PsiFile) file);
+    }
+
+    public static TargetPlatform getPlatform(@NotNull PsiFile file) {
+
         VirtualFile virtualFile = file.getOriginalFile().getVirtualFile();
         if (virtualFile == null) {
             return getDefaultPlatform(file);
         }
+
         Module moduleForFile = ProjectFileIndex.SERVICE.getInstance(file.getProject()).getModuleForFile(virtualFile);
         if (moduleForFile == null) {
             return getDefaultPlatform(file);
@@ -69,7 +75,7 @@ public class TargetPlatformDetector {
     }
 
     @NotNull
-    private static TargetPlatform getDefaultPlatform(@NotNull KtFile file) {
+    private static TargetPlatform getDefaultPlatform(@NotNull PsiFile file) {
         LOG.info("Using default platform for file: " + file.getName());
         return JvmPlatform.INSTANCE;
     }

idea/src/org/jetbrains/kotlin/idea/search/ideaExtensions/KotlinDirectInheritorsSearcher.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.idea.search.ideaExtensions
 
 import com.intellij.openapi.application.QueryExecutorBase
+import com.intellij.openapi.progress.ProgressManager
 import com.intellij.psi.PsiClass
 import com.intellij.psi.search.GlobalSearchScope
 import com.intellij.psi.search.searches.DirectClassInheritorsSearch
@@ -25,6 +26,7 @@ import org.jetbrains.kotlin.idea.decompiler.navigation.SourceNavigationHelper
 import org.jetbrains.kotlin.idea.search.fileScope
 import org.jetbrains.kotlin.idea.stubindex.KotlinSourceFilterScope
 import org.jetbrains.kotlin.idea.stubindex.KotlinSuperClassIndex
+import org.jetbrains.kotlin.idea.stubindex.KotlinTypeAliasByExpansionShortNameIndex
 import org.jetbrains.kotlin.idea.util.application.runReadAction
 
 open class KotlinDirectInheritorsSearcher : QueryExecutorBase<PsiClass, DirectClassInheritorsSearch.SearchParameters>(true) {
@@ -36,13 +38,35 @@ open class KotlinDirectInheritorsSearcher : QueryExecutorBase<PsiClass, DirectCl
         val originalScope = queryParameters.scope
         val scope = originalScope as? GlobalSearchScope ?: baseClass.containingFile?.fileScope() ?: return
 
+        val file = baseClass.containingFile
+
+        val names = mutableSetOf(name)
+        val project = file.project
+
+        val typeAliasIndex = KotlinTypeAliasByExpansionShortNameIndex.getInstance()
+
+        fun searchForTypeAliasesRecursively(typeName: String) {
+            ProgressManager.checkCanceled()
+            typeAliasIndex[typeName, project, scope].asSequence()
+                    .map { it.name }
+                    .filterNotNull()
+                    .filter { it !in names }
+                    .onEach { names.add(it) }
+                    .forEach(::searchForTypeAliasesRecursively)
+        }
+
+        searchForTypeAliasesRecursively(name)
+
         runReadAction {
             val noLibrarySourceScope = KotlinSourceFilterScope.projectSourceAndClassFiles(scope, baseClass.project)
-            KotlinSuperClassIndex.getInstance()
+
-                    .get(name, baseClass.project, noLibrarySourceScope).asSequence()
+            names.forEach { name ->
-                    .mapNotNull { candidate -> SourceNavigationHelper.getOriginalPsiClassOrCreateLightClass(candidate) }
+                KotlinSuperClassIndex.getInstance()
-                    .filter { candidate -> candidate.isInheritor(baseClass, false) }
+                        .get(name, baseClass.project, noLibrarySourceScope).asSequence()
-                    .forEach { candidate -> consumer.process(candidate) }
+                        .mapNotNull { candidate -> SourceNavigationHelper.getOriginalPsiClassOrCreateLightClass(candidate) }
+                        .filter { candidate -> candidate.isInheritor(baseClass, false) }
+                        .forEach { candidate -> consumer.process(candidate) }
+            }
         }
     }
 }

idea/testData/hierarchy/class/sub/MultiTypeAlias/MultiTypeAlias_verification.xml

@@ -0,0 +1,3 @@
+<node text="A ()" base="true">
+    <node text="B ()"/>
+</node>

idea/testData/hierarchy/class/sub/MultiTypeAlias/main.kt

@@ -0,0 +1,6 @@
+open class A<caret>
+
+typealias TA = A
+typealias TTA = A
+
+class B : TTA()

idea/testData/hierarchy/class/sub/TypeAlias/TypeAlias_verification.xml

@@ -0,0 +1,3 @@
+<node text="A ()" base="true">
+    <node text="B ()"/>
+</node>

idea/testData/hierarchy/class/sub/TypeAlias/main.kt

@@ -0,0 +1,5 @@
+open class A<caret>
+
+typealias TA = A
+
+class B : TA()

idea/testData/hierarchy/class/super/MultiTypeAlias/MultiTypeAlias_verification.xml

@@ -0,0 +1,5 @@
+<node text="B ()" base="true">
+    <node text="A ()">
+        <node text="Object (java.lang)"/>
+    </node>
+</node>

idea/testData/hierarchy/class/super/MultiTypeAlias/main.kt

@@ -0,0 +1,6 @@
+open class A
+
+typealias TA = A
+typealias TTA = A
+
+class B<caret> : TTA()

idea/testData/hierarchy/class/super/TypeAlias/TypeAlias_verification.xml

@@ -0,0 +1,5 @@
+<node text="B ()" base="true">
+    <node text="A ()">
+        <node text="Object (java.lang)"/>
+    </node>
+</node>

idea/testData/hierarchy/class/super/TypeAlias/main.kt

@@ -0,0 +1,5 @@
+open class A
+
+typealias TA = A
+
+class B<caret> : TA()

idea/tests/org/jetbrains/kotlin/idea/hierarchy/HierarchyTestGenerated.java

@@ -227,11 +227,23 @@ public class HierarchyTestGenerated extends AbstractHierarchyTest {
             doSuperClassHierarchyTest(fileName);
         }
 
+        @TestMetadata("MultiTypeAlias")
+        public void testMultiTypeAlias() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/super/MultiTypeAlias/");
+            doSuperClassHierarchyTest(fileName);
+        }
+
         @TestMetadata("TwoTraits")
         public void testTwoTraits() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/super/TwoTraits/");
             doSuperClassHierarchyTest(fileName);
         }
+
+        @TestMetadata("TypeAlias")
+        public void testTypeAlias() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/super/TypeAlias/");
+            doSuperClassHierarchyTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/hierarchy/class/sub")
@@ -266,6 +278,12 @@ public class HierarchyTestGenerated extends AbstractHierarchyTest {
             doSubClassHierarchyTest(fileName);
         }
 
+        @TestMetadata("MultiTypeAlias")
+        public void testMultiTypeAlias() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/sub/MultiTypeAlias/");
+            doSubClassHierarchyTest(fileName);
+        }
+
         @TestMetadata("ObjectFromClass")
         public void testObjectFromClass() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/sub/ObjectFromClass/");
@@ -289,6 +307,12 @@ public class HierarchyTestGenerated extends AbstractHierarchyTest {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/sub/TraitFromTrait/");
             doSubClassHierarchyTest(fileName);
         }
+
+        @TestMetadata("TypeAlias")
+        public void testTypeAlias() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/hierarchy/class/sub/TypeAlias/");
+            doSubClassHierarchyTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/hierarchy/calls/callers")