FIR IDE: fix resolving of inner type aliases

idea/idea-analysis/src/org/jetbrains/kotlin/idea/stubindex/IdeStubIndexService.java

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.fileClasses.JvmFileClassInfo;
 import org.jetbrains.kotlin.fileClasses.JvmFileClassUtil;
 import org.jetbrains.kotlin.lexer.KtTokens;
 import org.jetbrains.kotlin.load.java.JvmAbi;
+import org.jetbrains.kotlin.name.ClassId;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.psi.KtClassOrObject;
@@ -174,13 +175,18 @@ public class IdeStubIndexService extends StubIndexService {
 
         IndexUtilsKt.indexTypeAliasExpansion(stub, sink);
 
-        if (stub.isTopLevel()) {
-            FqName fqName = stub.getFqName();
-            if (fqName != null) {
+        FqName fqName = stub.getFqName();
+        if (fqName != null) {
+            if (stub.isTopLevel()) {
                 sink.occurrence(KotlinTopLevelTypeAliasFqNameIndex.getInstance().getKey(), fqName.asString());
                 sink.occurrence(KotlinTopLevelTypeAliasByPackageIndex.getInstance().getKey(), fqName.parent().asString());
             }
         }
+
+        ClassId classId = stub.getClassId();
+        if (classId != null && !stub.isTopLevel()) {
+            sink.occurrence(KotlinInnerTypeAliasClassIdIndex.getInstance().getKey(), classId.asString());
+        }
     }
 
     @Override

idea/idea-analysis/src/org/jetbrains/kotlin/idea/stubindex/KotlinInnerTypeAliasClassIdIndex.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2019 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.stubindex
+
+import com.intellij.openapi.project.Project
+import com.intellij.psi.search.GlobalSearchScope
+import com.intellij.psi.stubs.StringStubIndexExtension
+import com.intellij.psi.stubs.StubIndex
+import com.intellij.psi.stubs.StubIndexKey
+import org.jetbrains.kotlin.psi.KtTypeAlias
+
+/**
+ * Index of non-top-level type aliases (members of classes)
+ * The key is stringified [org.jetbrains.kotlin.name.ClassId] by the rules described in [org.jetbrains.kotlin.name.ClassId.asString]:
+ * packages are delimited by '/' and classes by '.', e.g. "kotlin/Map.Entry"
+ */
+class KotlinInnerTypeAliasClassIdIndex : StringStubIndexExtension<KtTypeAlias>() {
+    override fun getKey(): StubIndexKey<String, KtTypeAlias> = KEY
+
+    override fun get(s: String, project: Project, scope: GlobalSearchScope): Collection<KtTypeAlias> =
+        StubIndex.getElements(KEY, s, project, scope, KtTypeAlias::class.java)
+
+    companion object {
+        val KEY = KotlinIndexUtil.createIndexKey(KotlinInnerTypeAliasClassIdIndex::class.java)
+        val INSTANCE = KotlinInnerTypeAliasClassIdIndex()
+
+        @JvmStatic
+        fun getInstance() = INSTANCE
+    }
+}
+

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/IndexHelper.kt

@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.utils.addToStdlib.firstNotNullResult
 
 /*
 * Move to another module
@@ -28,7 +29,7 @@ public class IndexHelper(val project: Project, private val scope: GlobalSearchSc
     private inline fun <INDEX_KEY : Any, reified PSI : PsiElement> firstMatchingOrNull(
         stubKey: StubIndexKey<INDEX_KEY, PSI>,
         key: INDEX_KEY,
-        crossinline filter: (PSI) -> Boolean
+        crossinline filter: (PSI) -> Boolean = { true }
     ): PSI? {
         var result: PSI? = null
         stubIndex.processElements(
@@ -48,10 +49,14 @@ public class IndexHelper(val project: Project, private val scope: GlobalSearchSc
         classId.asStringForIndexes(),
     ) { candidate -> candidate.containingKtFile.packageFqName == classId.packageFqName }
 
-    fun typeAliasFromIndexByClassId(classId: ClassId) = firstMatchingOrNull(
+    fun typeAliasFromIndexByClassId(classId: ClassId): KtTypeAlias? = firstMatchingOrNull<String, KtTypeAlias>(
         KotlinTopLevelTypeAliasFqNameIndex.KEY,
-        classId.asStringForIndexes(),
+        key = classId.asStringForIndexes(),
     ) { candidate -> candidate.containingKtFile.packageFqName == classId.packageFqName }
+        ?: firstMatchingOrNull<String, KtTypeAlias>(
+            KotlinInnerTypeAliasClassIdIndex.KEY,
+            key = classId.asString(),
+        )
 
 
     fun getTopLevelProperties(callableId: CallableId): Collection<KtProperty> =

idea/resources/META-INF/indexes.xml

@@ -15,6 +15,7 @@
     <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinTopLevelFunctionFqnNameIndex"/>
     <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinTopLevelPropertyFqnNameIndex"/>
     <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinTopLevelTypeAliasFqNameIndex"/>
+    <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinInnerTypeAliasClassIdIndex"/>
     <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinTopLevelExtensionsByReceiverTypeIndex"/>
     <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinAnnotationsIndex"/>
     <stubIndex implementation="org.jetbrains.kotlin.idea.stubindex.KotlinProbablyNothingFunctionShortNameIndex"/>