Fix false positive "Unused import" for type alias

#KT-29977 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/KotlinUnusedImportInspection.kt

@@ -41,6 +41,7 @@ import com.intellij.psi.PsiFile
 import com.intellij.psi.PsiWhiteSpace
 import com.intellij.psi.util.PsiUtilBase
 import com.intellij.util.DocumentUtil
+import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.idea.core.targetDescriptors
 import org.jetbrains.kotlin.idea.imports.KotlinImportOptimizer
 import org.jetbrains.kotlin.idea.imports.OptimizedImportsBuilder
@@ -91,6 +92,7 @@ class KotlinUnusedImportInspection : AbstractKotlinInspection() {
             val importPaths = HashSet<ImportPath>(directives.size)
             val unusedImports = ArrayList<KtImportDirective>()
 
+            val resolutionFacade = file.getResolutionFacade()
             for (directive in directives) {
                 val importPath = directive.importPath ?: continue
                 if (importPath.alias != null) continue // highlighting of unused alias imports not supported yet
@@ -98,11 +100,13 @@ class KotlinUnusedImportInspection : AbstractKotlinInspection() {
                 val isUsed = when {
                     !importPaths.add(importPath) -> false
                     importPath.isAllUnder -> importPath.fqName in parentFqNames
-                    else -> importPath.fqName in fqNames
+                    importPath.fqName in fqNames -> true
+                    // case for type alias
+                    else -> directive.targetDescriptors(resolutionFacade).firstOrNull()?.let { it.importableFqName in fqNames } ?: false
                 }
 
                 if (!isUsed) {
-                    if (directive.targetDescriptors().isEmpty()) continue // do not highlight unresolved imports as unused
+                    if (directive.targetDescriptors(resolutionFacade).isEmpty()) continue // do not highlight unresolved imports as unused
                     unusedImports += directive
                 }
             }

idea/testData/quickfix/optimizeImports/notRemoveImportsForTypeAliases2.before.Dependency.kt

@@ -0,0 +1,5 @@
+package test
+
+import MyEnum
+
+typealias Other = MyEnum

idea/testData/quickfix/optimizeImports/notRemoveImportsForTypeAliases2.before.Main.kt

@@ -0,0 +1,10 @@
+// "Optimize imports" "false"
+// ACTION: Introduce import alias
+
+import test.Other.HELLO<caret>
+
+val ONE = HELLO
+
+enum class MyEnum {
+    HELLO
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixMultiFileTestGenerated.java

@@ -3291,6 +3291,11 @@ public class QuickFixMultiFileTestGenerated extends AbstractQuickFixMultiFileTes
         public void testNotRemoveImportsForTypeAliases() throws Exception {
             runTest("idea/testData/quickfix/optimizeImports/notRemoveImportsForTypeAliases.before.Main.kt");
         }
+
+        @TestMetadata("notRemoveImportsForTypeAliases2.before.Main.kt")
+        public void testNotRemoveImportsForTypeAliases2() throws Exception {
+            runTest("idea/testData/quickfix/optimizeImports/notRemoveImportsForTypeAliases2.before.Main.kt");
+        }
     }
 
     @TestMetadata("idea/testData/quickfix/override")