Optimize Imports shouldn't delete imports with unresolved parts

#KT-10512 Fixed

idea/ide-common/src/org/jetbrains/kotlin/idea/util/ImportsUtils.kt

@@ -20,7 +20,10 @@ package org.jetbrains.kotlin.idea.imports
 
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.psi.KtImportDirective
+import org.jetbrains.kotlin.psi.KtNameReferenceExpression
 import org.jetbrains.kotlin.psi.KtReferenceExpression
+import org.jetbrains.kotlin.psi.psiUtil.getQualifiedElementSelector
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.ImportPath
@@ -28,7 +31,6 @@ import org.jetbrains.kotlin.resolve.bindingContextUtil.getReferenceTargets
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.getImportableDescriptor
 import org.jetbrains.kotlin.types.KotlinType
-import java.util.*
 
 object ImportPathComparator : Comparator<ImportPath> {
     override fun compare(import1: ImportPath, import2: ImportPath): Int {
@@ -92,3 +94,5 @@ fun KtReferenceExpression.getImportableTargets(bindingContext: BindingContext):
     return targets.map { it.getImportableDescriptor() }.toSet()
 }
 
+fun KtImportDirective.canResolve(): Boolean = (importedReference?.getQualifiedElementSelector() as? KtNameReferenceExpression)
+    ?.reference?.resolve() != null ?: false

idea/ide-common/src/org/jetbrains/kotlin/idea/util/OptimizedImportsBuilder.kt

@@ -87,6 +87,11 @@ class OptimizedImportsBuilder(
     private val importRules = HashSet<ImportRule>()
 
     fun buildOptimizedImports(): List<ImportPath>? {
+        file.importDirectives
+            .filterNot(KtImportDirective::canResolve)
+            .mapNotNull(KtImportDirective::getImportPath)
+            .mapTo(importRules) { ImportRule.Add(it) }
+
         while (true) {
             val importRulesBefore = importRules.size
             val result = tryBuildOptimizedImports()