Fix codegen for multifile class parts with type aliases only

#KT-20337 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/MultifileClassCodegen.kt

@@ -368,7 +368,7 @@ class MultifileClassCodegenImpl(
         }
 
         private fun KtFile.hasDeclarationsForPartClass() =
-                CodegenUtil.getActualDeclarations(this).any { it is KtProperty || it is KtFunction }
+                CodegenUtil.getActualDeclarations(this).any { it is KtProperty || it is KtFunction || it is KtTypeAlias }
 
         private fun getCompiledPackageFragment(
                 facadeFqName: FqName, state: GenerationState

compiler/backend/src/org/jetbrains/kotlin/codegen/MultifileClassPartCodegen.kt

@@ -19,7 +19,6 @@ package org.jetbrains.kotlin.codegen
 import com.intellij.util.ArrayUtil
 import org.jetbrains.kotlin.backend.common.CodegenUtil
 import org.jetbrains.kotlin.codegen.context.MultifileClassPartContext
-import org.jetbrains.kotlin.codegen.serialization.JvmSerializerExtension
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
@@ -29,16 +28,13 @@ import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtNamedFunction
 import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtTypeAlias
-import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.MultifileClass
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.OtherOrigin
-import org.jetbrains.kotlin.serialization.DescriptorSerializer
 import org.jetbrains.org.objectweb.asm.MethodVisitor
 import org.jetbrains.org.objectweb.asm.Opcodes
 import org.jetbrains.org.objectweb.asm.Type
 import org.jetbrains.org.objectweb.asm.tree.AbstractInsnNode
 import org.jetbrains.org.objectweb.asm.tree.MethodInsnNode
-import java.util.*
 
 class MultifileClassPartCodegen(
         v: ClassBuilder,
@@ -162,25 +158,7 @@ class MultifileClassPartCodegen(
     }
 
     override fun generateKotlinMetadataAnnotation() {
-        val members = ArrayList<DeclarationDescriptor>()
-        for (declaration in CodegenUtil.getActualDeclarations(element)) {
-            when (declaration) {
-                is KtNamedFunction -> {
-                    val functionDescriptor = bindingContext.get(BindingContext.FUNCTION, declaration)
-                    members.add(functionDescriptor ?: throw AssertionError("Function ${declaration.name} is not bound in ${element.name}"))
-                }
-                is KtProperty -> {
-                    val property = bindingContext.get(BindingContext.VARIABLE, declaration)
-                    members.add(property ?: throw AssertionError("Property ${declaration.name} is not bound in ${element.name}"))
-                }
-            }
-        }
-
-        val extension = JvmSerializerExtension(v.serializationBindings, state)
-        val serializer = DescriptorSerializer.createTopLevel(extension)
-        val builder = serializer.packagePartProto(packageFragment.fqName, members)
-        extension.serializeJvmPackage(builder, partType)
-        val packageProto = builder.build()
+        val (serializer, packageProto) = PackagePartCodegen.serializePackagePartMembers(this, partType)
 
         val extraFlags = if (shouldGeneratePartHierarchy) JvmAnnotationNames.METADATA_MULTIFILE_PARTS_INHERIT_FLAG else 0
 

compiler/backend/src/org/jetbrains/kotlin/codegen/PackagePartCodegen.java

@@ -17,7 +17,9 @@
 package org.jetbrains.kotlin.codegen;
 
 import com.intellij.util.ArrayUtil;
+import kotlin.Pair;
 import kotlin.Unit;
+import kotlin.collections.CollectionsKt;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.backend.common.CodegenUtil;
 import org.jetbrains.kotlin.codegen.annotation.AnnotatedSimple;
@@ -25,9 +27,6 @@ import org.jetbrains.kotlin.codegen.context.FieldOwnerContext;
 import org.jetbrains.kotlin.codegen.serialization.JvmSerializerExtension;
 import org.jetbrains.kotlin.codegen.state.GenerationState;
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
-import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor;
-import org.jetbrains.kotlin.descriptors.TypeAliasDescriptor;
-import org.jetbrains.kotlin.descriptors.VariableDescriptor;
 import org.jetbrains.kotlin.descriptors.annotations.Annotated;
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor;
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationsImpl;
@@ -101,34 +100,42 @@ public class PackagePartCodegen extends MemberCodegen<KtFile> {
 
     @Override
     protected void generateKotlinMetadataAnnotation() {
-        List<DeclarationDescriptor> members = new ArrayList<>();
-        for (KtDeclaration declaration : CodegenUtil.getActualDeclarations(element)) {
-            if (declaration instanceof KtNamedFunction) {
-                SimpleFunctionDescriptor functionDescriptor = bindingContext.get(BindingContext.FUNCTION, declaration);
-                members.add(functionDescriptor);
-            }
-            else if (declaration instanceof KtProperty) {
-                VariableDescriptor property = bindingContext.get(BindingContext.VARIABLE, declaration);
-                members.add(property);
-            }
-            else if (declaration instanceof KtTypeAlias) {
-                TypeAliasDescriptor typeAlias = bindingContext.get(BindingContext.TYPE_ALIAS, declaration);
-                members.add(typeAlias);
-            }
-        }
-
-        JvmSerializerExtension extension = new JvmSerializerExtension(v.getSerializationBindings(), state);
-        DescriptorSerializer serializer = DescriptorSerializer.createTopLevel(extension);
-        ProtoBuf.Package.Builder builder = serializer.packagePartProto(element.getPackageFqName(), members);
-        extension.serializeJvmPackage(builder, packagePartType);
-        ProtoBuf.Package packageProto = builder.build();
+        Pair<DescriptorSerializer, ProtoBuf.Package> serializedPart = serializePackagePartMembers(this, packagePartType);
 
         WriteAnnotationUtilKt.writeKotlinMetadata(v, state, KotlinClassHeader.Kind.FILE_FACADE, 0, av -> {
-            writeAnnotationData(av, serializer, packageProto);
+            writeAnnotationData(av, serializedPart.getFirst(), serializedPart.getSecond());
             return Unit.INSTANCE;
         });
     }
 
+    @NotNull
+    protected static Pair<DescriptorSerializer, ProtoBuf.Package> serializePackagePartMembers(
+            @NotNull MemberCodegen<? extends KtFile> codegen,
+            @NotNull Type packagePartType
+    ) {
+        BindingContext bindingContext = codegen.bindingContext;
+        List<DeclarationDescriptor> members = CollectionsKt.mapNotNull(CodegenUtil.getActualDeclarations(codegen.element), declaration -> {
+            if (declaration instanceof KtNamedFunction) {
+                return bindingContext.get(BindingContext.FUNCTION, declaration);
+            }
+            else if (declaration instanceof KtProperty) {
+                return bindingContext.get(BindingContext.VARIABLE, declaration);
+            }
+            else if (declaration instanceof KtTypeAlias) {
+                return bindingContext.get(BindingContext.TYPE_ALIAS, declaration);
+            }
+
+            return null;
+        });
+
+        JvmSerializerExtension extension = new JvmSerializerExtension(codegen.v.getSerializationBindings(), codegen.state);
+        DescriptorSerializer serializer = DescriptorSerializer.createTopLevel(extension);
+        ProtoBuf.Package.Builder builder = serializer.packagePartProto(codegen.element.getPackageFqName(), members);
+        extension.serializeJvmPackage(builder, packagePartType);
+
+        return new Pair<>(serializer, builder.build());
+    }
+
     @Override
     protected void generateSyntheticPartsAfterBody() {
         generateSyntheticAccessors();

compiler/testData/compileKotlinAgainstKotlin/multifileClassWithTypealias.kt

@@ -0,0 +1,16 @@
+// IGNORE_BACKEND: NATIVE
+// FILE: A.kt
+
+@file:[JvmName("Test") JvmMultifileClass]
+
+typealias S = String
+typealias LS = List<S>
+
+// FILE: B.kt
+
+import java.util.Arrays
+
+fun box(): S {
+    val l: LS = Arrays.asList("OK")
+    return l[0]
+}

compiler/tests/org/jetbrains/kotlin/codegen/CompileKotlinAgainstKotlinTestGenerated.java

@@ -168,6 +168,12 @@ public class CompileKotlinAgainstKotlinTestGenerated extends AbstractCompileKotl
         doTest(fileName);
     }
 
+    @TestMetadata("multifileClassWithTypealias.kt")
+    public void testMultifileClassWithTypealias() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/compileKotlinAgainstKotlin/multifileClassWithTypealias.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("nestedClass.kt")
     public void testNestedClass() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/compileKotlinAgainstKotlin/nestedClass.kt");