Support naked files.

Implements https://github.com/wixtoolset/issues/issues/7696.

`File` elements can appear where `Component` elements do in WiX v4. The
compiler generates an appropriate per-file component. Naked files under
`Directory`, `DirectoryRef`, `Fragment`, `StandardDirectory`, or
`Package` elements are included in a package via the [default-feature
feature](https://github.com/wixtoolset/issues/issues/7581). Naked files
appearing under `ComponentGroup`, `Feature`, `FeatureRef`, and
`FeatureGroup` generate the component and the reference to the parent
element.

Components and naked Files default to being installed to INSTALLFOLDER
(including a default INSTALLFOLDER if one isn't otherwise authored).

27 files changed, 751 insertions, 120 deletions

diff --git a/src/api/wix/WixToolset.Data/ErrorMessages.cs b/src/api/wix/WixToolset.Data/ErrorMessages.cs
index e7c88613..79b835cd 100644
--- a/src/api/wix/WixToolset.Data/ErrorMessages.cs
+++ b/src/api/wix/WixToolset.Data/ErrorMessages.cs
@@ -2256,6 +2256,11 @@ namespace WixToolset.Data
             return Message(sourceLineNumbers, Ids.IllegalInnerText, "The {0} element contains inner text which is obsolete. Use the {1} attribute instead.", elementName, attributeName);
         }
 
+        public static Message IllegalAttributeWhenNested(SourceLineNumber sourceLineNumbers, string attributeName)
+        {
+            return Message(sourceLineNumbers, Ids.IllegalAttributeWhenNested, "The File element contains an attribute '{0}' that cannot be used in a File element that is a child of a Component element.", attributeName);
+        }
+
         private static Message Message(SourceLineNumber sourceLineNumber, Ids id, string format, params object[] args)
         {
             return new Message(sourceLineNumber, MessageLevel.Error, (int)id, format, args);
diff --git a/src/wix/WixToolset.Core/Compiler.cs b/src/wix/WixToolset.Core/Compiler.cs
index 7088cfba..bafe2c19 100644
--- a/src/wix/WixToolset.Core/Compiler.cs
+++ b/src/wix/WixToolset.Core/Compiler.cs
@@ -2252,9 +2252,11 @@ namespace WixToolset.Core
 
             if (String.IsNullOrEmpty(directoryId))
             {
-                this.Core.Write(ErrorMessages.ExpectedAttribute(sourceLineNumbers, node.Name.LocalName, "Directory"));
+                directoryId = "INSTALLFOLDER";
+                this.Core.CreateSimpleReference(sourceLineNumbers, SymbolDefinitions.Directory, directoryId);
             }
-            else if (!String.IsNullOrEmpty(subdirectory))
+
+            if (!String.IsNullOrEmpty(subdirectory))
             {
                 directoryId = this.Core.CreateDirectoryReferenceFromInlineSyntax(sourceLineNumbers, directoryId, subdirectory);
             }
@@ -2427,6 +2429,7 @@ namespace WixToolset.Core
                                     keyBit = ComponentKeyPathType.File;
                                     keyPossible = possibleKeyPath.Id;
                                     break;
+
                                 case PossibleKeyPathType.Directory:
                                     keyBit = ComponentKeyPathType.Directory;
                                     keyPossible = String.Empty;
@@ -2581,8 +2584,8 @@ namespace WixToolset.Core
         /// Parses a component group element.
         /// </summary>
         /// <param name="node">Element to parse.</param>
-        /// <param name="parentType"></param>
-        /// <param name="parentId"></param>
+        /// <param name="parentType">Type of complex reference parent. Will be Unknown if there is no parent.</param>
+        /// <param name="parentId">Optional identifier for primary parent.</param>
         private void ParseComponentGroupElement(XElement node, ComplexReferenceParentType parentType, string parentId)
         {
             var sourceLineNumbers = Preprocessor.GetSourceLineNumbers(node);
@@ -2649,6 +2652,9 @@ namespace WixToolset.Core
                     case "Component":
                         this.ParseComponentElement(child, ComplexReferenceParentType.ComponentGroup, id.Id, null, CompilerConstants.IntegerNotSet, directoryId, source);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.ComponentGroup, id.Id, directoryId, source);
+                        break;
                     default:
                         this.Core.UnexpectedElement(node, child);
                         break;
@@ -3872,6 +3878,9 @@ namespace WixToolset.Core
                     case "Directory":
                         this.ParseDirectoryElement(child, id.Id, diskId, fileSource);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.Unknown, null, id.Id, fileSource);
+                        break;
                     case "Merge":
                         this.ParseMergeElement(child, id.Id, diskId);
                         break;
@@ -3984,6 +3993,9 @@ namespace WixToolset.Core
                     case "Directory":
                         this.ParseDirectoryElement(child, id, diskId, fileSource);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.Unknown, null, id, fileSource);
+                        break;
                     case "Merge":
                         this.ParseMergeElement(child, id, diskId);
                         break;
@@ -4421,6 +4433,9 @@ namespace WixToolset.Core
                     case "FeatureRef":
                         this.ParseFeatureRefElement(child, ComplexReferenceParentType.Feature, id.Id);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.Feature, id.Id, null, null);
+                        break;
                     case "Level":
                         this.ParseLevelElement(child, id.Id);
                         break;
@@ -4561,6 +4576,9 @@ namespace WixToolset.Core
                     case "FeatureRef":
                         this.ParseFeatureRefElement(child, ComplexReferenceParentType.Feature, id);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.Feature, id, null, null);
+                        break;
                     case "MergeRef":
                         this.ParseMergeRefElement(child, ComplexReferenceParentType.Feature, id);
                         break;
@@ -4646,6 +4664,9 @@ namespace WixToolset.Core
                     case "FeatureRef":
                         this.ParseFeatureRefElement(child, ComplexReferenceParentType.FeatureGroup, id.Id);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.FeatureGroup, id.Id, null, null);
+                        break;
                     case "MergeRef":
                         this.ParseMergeRefElement(child, ComplexReferenceParentType.FeatureGroup, id.Id);
                         break;
@@ -5029,9 +5050,8 @@ namespace WixToolset.Core
             }
         }
 
-
         /// <summary>
-        /// Parses a file element.
+        /// Parses a File element's attributes.
         /// </summary>
         /// <param name="node">File element to parse.</param>
         /// <param name="componentId">Parent's component id.</param>
@@ -5039,10 +5059,12 @@ namespace WixToolset.Core
         /// <param name="diskId">Disk id inherited from parent component.</param>
         /// <param name="sourcePath">Default source path of parent directory.</param>
         /// <param name="possibleKeyPath">This will be set with the possible keyPath for the parent component.</param>
-        /// <param name="win64Component">true if the component is 64-bit.</param>
-        /// <param name="componentGuid"></param>
+        /// <param name="componentGuid">Component GUID (including `*`).</param>
+        /// <param name="isNakedFile">Whether the File element being parsed is outside a Component element.</param>
+        /// <param name="fileSymbol">Outgoing file symbol containing parsed attributes.</param>
+        /// <param name="assemblySymbol">Outgoing assembly symbol containing parsed attributes.</param>
         /// <returns>Yes if this element was marked as the parent component's key path, No if explicitly marked as not being a key path, or NotSet otherwise.</returns>
-        private YesNoType ParseFileElement(XElement node, string componentId, string directoryId, int diskId, string sourcePath, out string possibleKeyPath, bool win64Component, string componentGuid)
+        private YesNoType ParseFileElementAttributes(XElement node, string componentId, string directoryId, int diskId, string sourcePath, out string possibleKeyPath, string componentGuid, bool isNakedFile, out FileSymbol fileSymbol, out AssemblySymbol assemblySymbol)
         {
             var sourceLineNumbers = Preprocessor.GetSourceLineNumbers(node);
             Identifier id = null;
@@ -5083,12 +5105,25 @@ namespace WixToolset.Core
             var source = sourcePath;   // assume we'll use the parents as the source for this file
             var sourceSet = false;
 
+            fileSymbol = null;
+            assemblySymbol = null;
+
             foreach (var attrib in node.Attributes())
             {
                 if (String.IsNullOrEmpty(attrib.Name.NamespaceName) || CompilerCore.WixNamespace == attrib.Name.Namespace)
                 {
                     switch (attrib.Name.LocalName)
                     {
+                    case "Bitness":
+                    case "Condition":
+                    case "Directory":
+                    case "Subdirectory":
+                        // Naked files handle their attributes in ParseNakedFileElement.
+                        if (!isNakedFile)
+                        {
+                            this.Messaging.Write(ErrorMessages.IllegalAttributeWhenNested(sourceLineNumbers, attrib.Name.LocalName));
+                        }
+                        break;
                     case "Id":
                         id = this.Core.GetAttributeIdentifier(sourceLineNumbers, attrib);
                         break;
@@ -5329,70 +5364,6 @@ namespace WixToolset.Core
                 }
             }
 
-            foreach (var child in node.Elements())
-            {
-                if (CompilerCore.WixNamespace == child.Name.Namespace)
-                {
-                    switch (child.Name.LocalName)
-                    {
-                    case "AppId":
-                        this.ParseAppIdElement(child, componentId, YesNoType.NotSet, id.Id, null, null);
-                        break;
-                    case "AssemblyName":
-                        this.ParseAssemblyName(child, componentId);
-                        break;
-                    case "Class":
-                        this.ParseClassElement(child, componentId, YesNoType.NotSet, id.Id, null, null, null);
-                        break;
-                    case "CopyFile":
-                        this.ParseCopyFileElement(child, componentId, id.Id);
-                        break;
-                    case "IgnoreRange":
-                        this.ParseRangeElement(child, ref ignoreOffsets, ref ignoreLengths);
-                        break;
-                    case "ODBCDriver":
-                        this.ParseODBCDriverOrTranslator(child, componentId, id.Id, SymbolDefinitionType.ODBCDriver);
-                        break;
-                    case "ODBCTranslator":
-                        this.ParseODBCDriverOrTranslator(child, componentId, id.Id, SymbolDefinitionType.ODBCTranslator);
-                        break;
-                    case "Permission":
-                        this.ParsePermissionElement(child, id.Id, "File");
-                        break;
-                    case "PermissionEx":
-                        this.ParsePermissionExElement(child, id.Id, "File");
-                        break;
-                    case "ProtectRange":
-                        this.ParseRangeElement(child, ref protectOffsets, ref protectLengths);
-                        break;
-                    case "Shortcut":
-                        this.ParseShortcutElement(child, componentId, node.Name.LocalName, id.Id, keyPath);
-                        break;
-                    case "SymbolPath":
-                        if (null != symbols)
-                        {
-                            symbols += ";" + this.ParseSymbolPathElement(child);
-                        }
-                        else
-                        {
-                            symbols = this.ParseSymbolPathElement(child);
-                        }
-                        break;
-                    case "TypeLib":
-                        this.ParseTypeLibElement(child, componentId, id.Id, win64Component);
-                        break;
-                    default:
-                        this.Core.UnexpectedElement(node, child);
-                        break;
-                    }
-                }
-                else
-                {
-                    var context = new Dictionary<string, string>() { { "FileId", id?.Id }, { "ComponentId", componentId }, { "DirectoryId", directoryId }, { "Win64", win64Component.ToString() } };
-                    this.Core.ParseExtensionElement(node, child, context);
-                }
-            }
-
             if (!this.Core.EncounteredError)
             {
                 var patchAttributes = PatchAttributeType.None;
@@ -5427,7 +5398,7 @@ namespace WixToolset.Core
                 attributes |= compressed.HasValue && compressed == true ? FileSymbolAttributes.Compressed : 0;
                 attributes |= compressed.HasValue && compressed == false ? FileSymbolAttributes.Uncompressed : 0;
 
-                this.Core.AddSymbol(new FileSymbol(sourceLineNumbers, id)
+                fileSymbol = new FileSymbol(sourceLineNumbers, id)
                 {
                     ComponentRef = componentId,
                     Name = name,
@@ -5454,11 +5425,11 @@ namespace WixToolset.Core
                     IgnoreLengths = ignoreLengths,
                     RetainOffsets = protectOffsets,
                     SymbolPaths = symbols,
-                });
+                };
 
                 if (AssemblyType.NotAnAssembly != assemblyType)
                 {
-                    this.Core.AddSymbol(new AssemblySymbol(sourceLineNumbers, id)
+                    assemblySymbol = new AssemblySymbol(sourceLineNumbers, id)
                     {
                         ComponentRef = componentId,
                         FeatureRef = Guid.Empty.ToString("B"),
@@ -5466,7 +5437,7 @@ namespace WixToolset.Core
                         ApplicationFileRef = assemblyApplication,
                         Type = assemblyType,
                         ProcessorArchitecture = procArch,
-                    });
+                    };
                 }
             }
 
@@ -5485,6 +5456,227 @@ namespace WixToolset.Core
             return keyPath;
         }
 
+        /// <param name="node">File element to parse.</param>
+        /// <param name="fileSymbol">The partially-parsed file symbol.</param>
+        /// <param name="keyPath">Whether the file is the keypath of its component.</param>
+        /// <param name="win64Component">true if the component is 64-bit.</param>
+        private void ParseFileElementChildren(XElement node, FileSymbol fileSymbol, YesNoType keyPath, bool win64Component)
+        {
+            var directoryId = fileSymbol.DirectoryRef;
+            var componentId = fileSymbol.ComponentRef;
+            var id = fileSymbol.Id;
+            var ignoreOffsets = fileSymbol.IgnoreOffsets;
+            var ignoreLengths = fileSymbol.IgnoreLengths;
+            var protectOffsets = fileSymbol.RetainOffsets;
+            var protectLengths = fileSymbol.RetainLengths;
+            var symbols = fileSymbol.SymbolPaths;
+
+            foreach (var child in node.Elements())
+            {
+                if (CompilerCore.WixNamespace == child.Name.Namespace)
+                {
+                    switch (child.Name.LocalName)
+                    {
+                    case "AppId":
+                        this.ParseAppIdElement(child, componentId, YesNoType.NotSet, id.Id, null, null);
+                        break;
+                    case "AssemblyName":
+                        this.ParseAssemblyName(child, componentId);
+                        break;
+                    case "Class":
+                        this.ParseClassElement(child, componentId, YesNoType.NotSet, id.Id, null, null, null);
+                        break;
+                    case "CopyFile":
+                        this.ParseCopyFileElement(child, componentId, id.Id);
+                        break;
+                    case "IgnoreRange":
+                        this.ParseRangeElement(child, ref ignoreOffsets, ref ignoreLengths);
+                        break;
+                    case "ODBCDriver":
+                        this.ParseODBCDriverOrTranslator(child, componentId, id.Id, SymbolDefinitionType.ODBCDriver);
+                        break;
+                    case "ODBCTranslator":
+                        this.ParseODBCDriverOrTranslator(child, componentId, id.Id, SymbolDefinitionType.ODBCTranslator);
+                        break;
+                    case "Permission":
+                        this.ParsePermissionElement(child, id.Id, "File");
+                        break;
+                    case "PermissionEx":
+                        this.ParsePermissionExElement(child, id.Id, "File");
+                        break;
+                    case "ProtectRange":
+                        this.ParseRangeElement(child, ref protectOffsets, ref protectLengths);
+                        break;
+                    case "Shortcut":
+                        this.ParseShortcutElement(child, componentId, node.Name.LocalName, id.Id, keyPath);
+                        break;
+                    case "SymbolPath":
+                        if (null != symbols)
+                        {
+                            symbols += ";" + this.ParseSymbolPathElement(child);
+                        }
+                        else
+                        {
+                            symbols = this.ParseSymbolPathElement(child);
+                        }
+                        break;
+                    case "TypeLib":
+                        this.ParseTypeLibElement(child, componentId, id.Id, win64Component);
+                        break;
+                    default:
+                        this.Core.UnexpectedElement(node, child);
+                        break;
+                    }
+                }
+                else
+                {
+                    var context = new Dictionary<string, string>() { { "FileId", id?.Id }, { "ComponentId", componentId }, { "DirectoryId", directoryId }, { "Win64", win64Component.ToString() } };
+                    this.Core.ParseExtensionElement(node, child, context);
+                }
+            }
+
+            fileSymbol.IgnoreOffsets = ignoreOffsets;
+            fileSymbol.IgnoreLengths = ignoreLengths;
+            fileSymbol.RetainOffsets = protectOffsets;
+            fileSymbol.RetainLengths = protectLengths;
+            fileSymbol.SymbolPaths = symbols;
+        }
+
+
+        /// <summary>
+        /// Parses a File element.
+        /// </summary>
+        /// <param name="node">File element to parse.</param>
+        /// <param name="componentId">Parent's component id.</param>
+        /// <param name="directoryId">Ancestor's directory id.</param>
+        /// <param name="diskId">Disk id inherited from parent component.</param>
+        /// <param name="sourcePath">Default source path of parent directory.</param>
+        /// <param name="possibleKeyPath">This will be set with the possible keyPath for the parent component.</param>
+        /// <param name="win64Component">true if the component is 64-bit.</param>
+        /// <param name="componentGuid">Component GUID (including `*`).</param>
+        /// <returns>Yes if this element was marked as the parent component's key path, No if explicitly marked as not being a key path, or NotSet otherwise.</returns>
+        private YesNoType ParseFileElement(XElement node, string componentId, string directoryId, int diskId, string sourcePath, out string possibleKeyPath, bool win64Component, string componentGuid)
+        {
+            var keyPath = this.ParseFileElementAttributes(node, componentId, directoryId, diskId, sourcePath, out possibleKeyPath, componentGuid, isNakedFile: false, out var fileSymbol, out var assemblySymbol);
+
+            if (!this.Core.EncounteredError)
+            {
+                this.Core.AddSymbol(fileSymbol);
+
+                if (assemblySymbol != null)
+                {
+                    this.Core.AddSymbol(assemblySymbol);
+                }
+
+                this.ParseFileElementChildren(node, fileSymbol, keyPath, win64Component);
+            }
+
+            return keyPath;
+        }
+
+        /// <summary>
+        /// Parses a file element outside a component.
+        /// </summary>
+        /// <param name="node">File element to parse.</param>
+        /// <param name="parentType">Type of complex reference parent. Will be Unknown if there is no parent.</param>
+        /// <param name="parentId">Optional identifier for primary parent.</param>
+        /// <param name="directoryId">Ancestor's directory id.</param>
+        /// <param name="sourcePath">Default source path of parent directory.</param>
+        /// <returns>Yes if this element was marked as the parent component's key path, No if explicitly marked as not being a key path, or NotSet otherwise.</returns>
+        private void ParseNakedFileElement(XElement node, ComplexReferenceParentType parentType, string parentId, string directoryId, string sourcePath)
+        {
+            var sourceLineNumbers = Preprocessor.GetSourceLineNumbers(node);
+            var win64 = this.Context.IsCurrentPlatform64Bit;
+            string condition = null;
+            string subdirectory = null;
+
+            var keyPath = this.ParseFileElementAttributes(node, "@WixTemporaryComponentId", directoryId, diskId: CompilerConstants.IntegerNotSet, sourcePath, out var _, componentGuid: "*", isNakedFile: true, out var fileSymbol, out var assemblySymbol);
+
+            if (!this.Core.EncounteredError)
+            {
+                // Naked files have additional attributes to handle common component attributes.
+                foreach (var attrib in node.Attributes())
+                {
+                    if (String.IsNullOrEmpty(attrib.Name.NamespaceName) || CompilerCore.WixNamespace == attrib.Name.Namespace)
+                    {
+                        switch (attrib.Name.LocalName)
+                        {
+                        case "Bitness":
+                            var bitnessValue = this.Core.GetAttributeValue(sourceLineNumbers, attrib);
+                            switch (bitnessValue)
+                            {
+                                case "always32":
+                                    win64 = false;
+                                    break;
+                                case "always64":
+                                    win64 = true;
+                                    break;
+                                case "default":
+                                case "":
+                                    break;
+                                default:
+                                    this.Core.Write(ErrorMessages.IllegalAttributeValue(sourceLineNumbers, node.Name.LocalName, attrib.Name.LocalName, bitnessValue, "default", "always32", "always64"));
+                                    break;
+                            }
+                            break;
+                        case "Condition":
+                            condition = this.Core.GetAttributeValue(sourceLineNumbers, attrib);
+                            break;
+                        case "Directory":
+                            directoryId = this.Core.GetAttributeIdentifierValue(sourceLineNumbers, attrib);
+                            this.Core.CreateSimpleReference(sourceLineNumbers, SymbolDefinitions.Directory, directoryId);
+                            break;
+                        case "Subdirectory":
+                            subdirectory = this.Core.GetAttributeLongFilename(sourceLineNumbers, attrib, allowRelative: true);
+                            break;
+                        }
+                    }
+                }
+
+                if (String.IsNullOrEmpty(directoryId))
+                {
+                    directoryId = "INSTALLFOLDER";
+                    this.Core.CreateSimpleReference(sourceLineNumbers, SymbolDefinitions.Directory, directoryId);
+                }
+
+                directoryId = this.HandleSubdirectory(sourceLineNumbers, node, directoryId, subdirectory, "Directory", "Subdirectory");
+
+                this.Core.AddSymbol(new ComponentSymbol(sourceLineNumbers, fileSymbol.Id)
+                {
+                    ComponentId = "*",
+                    DirectoryRef = directoryId,
+                    Location = ComponentLocation.LocalOnly,
+                    Condition = condition,
+                    KeyPath = fileSymbol.Id.Id,
+                    KeyPathType = ComponentKeyPathType.File,
+                    DisableRegistryReflection = false,
+                    NeverOverwrite = false,
+                    Permanent = false,
+                    SharedDllRefCount = false,
+                    Shared = false,
+                    Transitive = false,
+                    UninstallWhenSuperseded = false,
+                    Win64 = win64,
+                });
+
+                fileSymbol.ComponentRef = fileSymbol.Id.Id;
+                this.Core.AddSymbol(fileSymbol);
+
+                if (assemblySymbol != null)
+                {
+                    this.Core.AddSymbol(assemblySymbol);
+                }
+
+                this.ParseFileElementChildren(node, fileSymbol, keyPath, win64);
+
+                if (ComplexReferenceParentType.Unknown != parentType && null != parentId) // if parent was provided, add a complex reference to that.
+                {
+                    // If the naked file's component is defined directly under a feature, then mark the complex reference primary.
+                    this.Core.CreateComplexReference(sourceLineNumbers, parentType, parentId, null, ComplexReferenceChildType.Component, fileSymbol.Id.Id, ComplexReferenceParentType.Feature == parentType);
+                }
+            }
+        }
+
         /// <summary>
         /// Parses a file search element.
         /// </summary>
@@ -5802,6 +5994,9 @@ namespace WixToolset.Core
                     case "FeatureRef":
                         this.ParseFeatureRefElement(child, ComplexReferenceParentType.Unknown, null);
                         break;
+                    case "File":
+                        this.ParseNakedFileElement(child, ComplexReferenceParentType.Unknown, null, null, null);
+                        break;
                     case "Icon":
                         this.ParseIconElement(child);
                         break;
@@ -7149,6 +7344,9 @@ namespace WixToolset.Core
                         case "Directory":
                             this.ParseDirectoryElement(child, id, diskId: CompilerConstants.IntegerNotSet, fileSource: String.Empty);
                             break;
+                        case "File":
+                            this.ParseNakedFileElement(child, ComplexReferenceParentType.Unknown, null, id, null);
+                            break;
                         case "Merge":
                             this.ParseMergeElement(child, id, diskId: CompilerConstants.IntegerNotSet);
                             break;
@@ -7300,7 +7498,7 @@ namespace WixToolset.Core
         /// Parses a merge reference element.
         /// </summary>
         /// <param name="node">Element to parse.</param>
-        /// <param name="parentType">Parents complex reference type.</param>
+        /// <param name="parentType">Parent's complex reference type.</param>
         /// <param name="parentId">Identifier for parent feature or feature group.</param>
         private void ParseMergeRefElement(XElement node, ComplexReferenceParentType parentType, string parentId)
         {
diff --git a/src/wix/WixToolset.Core/Compiler_Module.cs b/src/wix/WixToolset.Core/Compiler_Module.cs
index 092f3473..19f57773 100644
--- a/src/wix/WixToolset.Core/Compiler_Module.cs
+++ b/src/wix/WixToolset.Core/Compiler_Module.cs
@@ -175,6 +175,9 @@ namespace WixToolset.Core
                         case "Exclusion":
                             this.ParseExclusionElement(child);
                             break;
+                        case "File":
+                            this.ParseNakedFileElement(child, ComplexReferenceParentType.Module, this.activeName, null, null);
+                            break;
                         case "Icon":
                             this.ParseIconElement(child);
                             break;
diff --git a/src/wix/WixToolset.Core/Compiler_Package.cs b/src/wix/WixToolset.Core/Compiler_Package.cs
index 31b8e81c..220a2a76 100644
--- a/src/wix/WixToolset.Core/Compiler_Package.cs
+++ b/src/wix/WixToolset.Core/Compiler_Package.cs
@@ -303,6 +303,9 @@ namespace WixToolset.Core
                         case "FeatureGroupRef":
                             this.ParseFeatureGroupRefElement(child, ComplexReferenceParentType.Product, productCode);
                             break;
+                        case "File":
+                            this.ParseNakedFileElement(child, ComplexReferenceParentType.Product, productCode, null, null);
+                            break;
                         case "Icon":
                             this.ParseIconElement(child);
                             break;
diff --git a/src/wix/WixToolset.Core/Link/AddDefaultSymbolsCommand.cs b/src/wix/WixToolset.Core/Link/AddDefaultSymbolsCommand.cs
index 8d9f7cab..28ad9351 100644
--- a/src/wix/WixToolset.Core/Link/AddDefaultSymbolsCommand.cs
+++ b/src/wix/WixToolset.Core/Link/AddDefaultSymbolsCommand.cs
@@ -32,6 +32,7 @@ namespace WixToolset.Core.Link
                 return;
             }
 
+            // If a directory with id INSTALLFOLDER hasn't been authored, provide a default one.
             if (!this.Find.SymbolsByName.ContainsKey(WixStandardInstallFolderReference))
             {
                 var sourceLineNumber = new SourceLineNumber("DefaultInstallFolder");
@@ -51,6 +52,9 @@ namespace WixToolset.Core.Link
                 );
             }
 
+            // If an upgrade hasn't been authored and the upgrade strategy is MajorUpgrade,
+            // conjure a default major upgrade with the stdlib localization string for the
+            // downgrade error message.
             var symbols = this.Sections.SelectMany(section => section.Symbols);
             var upgradeSymbols = symbols.OfType<UpgradeSymbol>();
             if (!upgradeSymbols.Any())
diff --git a/src/wix/WixToolset.Core/Link/SymbolWithSection.cs b/src/wix/WixToolset.Core/Link/SymbolWithSection.cs
index 5bdf8360..c00cce40 100644
--- a/src/wix/WixToolset.Core/Link/SymbolWithSection.cs
+++ b/src/wix/WixToolset.Core/Link/SymbolWithSection.cs
@@ -4,6 +4,7 @@ namespace WixToolset.Core.Link
 {
     using System;
     using System.Collections.Generic;
+    using System.Diagnostics;
     using System.Linq;
     using WixToolset.Data;
     using WixToolset.Data.Symbols;
@@ -11,6 +12,7 @@ namespace WixToolset.Core.Link
     /// <summary>
     /// Symbol with section representing a single unique symbol.
     /// </summary>
+    [DebuggerDisplay("{Symbol.DebuggerDisplay}")]
     internal class SymbolWithSection
     {
         private List<WixSimpleReferenceSymbol> directReferences;
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/ComponentFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/ComponentFixture.cs
index 9348afa5..71b80783 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/ComponentFixture.cs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/ComponentFixture.cs
@@ -41,34 +41,5 @@ namespace WixToolsetTest.CoreIntegration
                 }, errors.Select(e => e.Id).ToArray());
             }
         }
-
-        [Fact]
-        public void CannotBuildMissingDirectoryAttributeWithSubdirectory()
-        {
-            var folder = TestData.Get(@"TestData");
-
-            using (var fs = new DisposableFileSystem())
-            {
-                var baseFolder = fs.GetFolder();
-                var intermediateFolder = Path.Combine(baseFolder, "obj");
-                var msiPath = Path.Combine(baseFolder, "bin", "test.msi");
-
-                var result = WixRunner.Execute(new[]
-                {
-                    "build",
-                    Path.Combine(folder, "Component", "MissingDirectoryWithSubdirectory.wxs"),
-                    Path.Combine(folder, "ProductWithComponentGroupRef", "Product.wxs"),
-                    "-bindpath", Path.Combine(folder, "SingleFile", "data"),
-                    "-intermediateFolder", intermediateFolder,
-                    "-o", msiPath
-                });
-
-                var errors = result.Messages.Select(m => m.ToString()).ToArray();
-                WixAssert.CompareLineByLine(new[]
-                {
-                    "The Component/@Directory attribute was not found; it is required."
-                }, errors);
-            }
-        }
     }
 }
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/NakedFileFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/NakedFileFixture.cs
new file mode 100644
index 00000000..6d874ff0
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/NakedFileFixture.cs
@@ -0,0 +1,247 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolsetTest.CoreIntegration
+{
+    using System.Data;
+    using System.IO;
+    using System.Linq;
+    using WixInternal.Core.TestPackage;
+    using WixInternal.TestSupport;
+    using WixToolset.Data.WindowsInstaller;
+    using Xunit;
+
+    public class NakedFileFixture
+    {
+        [Fact]
+        public void CanBuildNakedFilesInComponentGroup()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("ComponentGroup.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInFeature()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("Feature.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInDirectory()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("Directory.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInDirectoryRef()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("DirectoryRef.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInFeatureRef()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("FeatureRef.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInFeatureGroup()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("FeatureGroup.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInFragments()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("Fragment.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInStandardDirectory()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("StandardDirectory.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesInModule()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("Module.wxs", isPackage: false);
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesWithConditions()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("Condition.wxs");
+            var componentRows = rows.Where(row => row.StartsWith("Component:")).ToArray();
+
+            // Coincidentally, the files' ids are the same as the component conditions.
+            foreach (var componentRow in componentRows)
+            {
+                var columns = componentRow.Split(':', '\t');
+                Assert.Equal(columns[1], columns[5]);
+            }
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesUnderPackage()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("Package.wxs");
+            AssertFileComponentIds(4, rows);
+        }
+
+        [Fact]
+        public void CanBuildNakedFilesUnderPackageWithDefaultInstallFolder()
+        {
+            var rows = BuildAndQueryComponentAndFileTables("PackageWithDefaultInstallFolder.wxs");
+            AssertFileComponentIds(4, rows);
+        }
+
+        [Fact]
+        public void NakedFilesUnderPackageWithAuthoredFeatureAreOrphaned()
+        {
+            var messages = BuildAndQueryComponentAndFileTables("PackageWithoutDefaultFeature.wxs", isPackage: true, 267);
+            Assert.Equal(new[]
+            {
+                "267",
+                "267",
+            }, messages);
+        }
+
+        [Fact]
+        public void IllegalAttributesWhenNonNakedFailTheBuild()
+        {
+            var messages = BuildAndQueryComponentAndFileTables("BadAttributes.wxs", isPackage: true, 62);
+            Assert.Equal(new[]
+            {
+                "62",
+                "62",
+                "62",
+                "62",
+            }, messages);
+        }
+
+        [Fact]
+        public void CanBuildNakedFileFromWixlibComponentGroup()
+        {
+            var rows = BuildPackageWithWixlib("WixlibComponentGroup.wxs", "WixlibComponentGroupPackage.wxs");
+
+            AssertFileComponentIds(2, rows);
+        }
+
+        private static string[] BuildPackageWithWixlib(string wixlibSourcePath, string msiSourcePath)
+        {
+            var folder = TestData.Get("TestData", "NakedFile");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var intermediateFolder = Path.Combine(baseFolder, "obj");
+                var binFolder = Path.Combine(baseFolder, "bin");
+                var wixlibPath = Path.Combine(binFolder, Path.ChangeExtension(wixlibSourcePath, ".wixlib"));
+
+                var result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, wixlibSourcePath),
+                    "-intermediateFolder", intermediateFolder,
+                    "-bindpath", folder,
+                    "-o", wixlibPath,
+                });
+
+                result.AssertSuccess();
+
+                var msiPath = Path.Combine(binFolder, "test.msi");
+
+                result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, msiSourcePath),
+                    wixlibPath,
+                    "-intermediateFolder", intermediateFolder,
+                    "-bindpath", folder,
+                    "-o", msiPath,
+                });
+                result.AssertSuccess();
+
+                return Query.QueryDatabase(msiPath, new[] { "Component", "File" })
+                    .OrderBy(s => s)
+                    .ToArray();
+            }
+        }
+
+        private static string[] BuildAndQueryComponentAndFileTables(string file, bool isPackage = true, int? exitCode = null)
+        {
+            var folder = TestData.Get("TestData", "NakedFile");
+
+            using (var fs = new DisposableFileSystem())
+            {
+                var baseFolder = fs.GetFolder();
+                var intermediateFolder = Path.Combine(baseFolder, "obj");
+                var binFolder = Path.Combine(baseFolder, "bin");
+                var msiPath = Path.Combine(binFolder, isPackage ? "test.msi" : "test.msm");
+
+                var result = WixRunner.Execute(new[]
+                {
+                    "build",
+                    Path.Combine(folder, file),
+                    "-intermediateFolder", intermediateFolder,
+                    "-bindpath", folder,
+                    "-o", msiPath,
+                });
+
+                if (exitCode.HasValue)
+                {
+                    Assert.Equal(exitCode.Value, result.ExitCode);
+
+                    return result.Messages.Select(m => m.Id.ToString()).ToArray();
+                }
+                else
+                {
+                    result.AssertSuccess();
+
+                    return Query.QueryDatabase(msiPath, new[] { "Component", "File" })
+                        .OrderBy(s => s)
+                        .ToArray();
+                }
+            }
+        }
+
+        private static void AssertFileComponentIds(int fileCount, string[] rows)
+        {
+            var componentRows = rows.Where(row => row.StartsWith("Component:")).ToArray();
+            var fileRows = rows.Where(row => row.StartsWith("File:")).ToArray();
+
+            Assert.Equal(fileCount, componentRows.Length);
+            Assert.Equal(componentRows.Length, fileRows.Length);
+
+            // Component id == Component keypath == File id
+            foreach (var componentRow in componentRows)
+            {
+                var columns = componentRow.Split(':', '\t');
+                Assert.Equal(columns[1], columns[6]);
+            }
+
+            foreach (var fileRow in fileRows)
+            {
+                var columns = fileRow.Split(':', '\t');
+                Assert.Equal(columns[1], columns[2]);
+            }
+        }
+    }
+}
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Component/MissingDirectoryWithSubdirectory.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Component/MissingDirectoryWithSubdirectory.wxs
deleted file mode 100644
index cefa9abc..00000000
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/Component/MissingDirectoryWithSubdirectory.wxs
+++ /dev/null
@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
-    <Fragment>
-        <ComponentGroup Id="ProductComponents">
-            <Component Subdirectory="fails\without\Directory\attribute">
-                <File Source="test.txt" />
-            </Component>
-        </ComponentGroup>
-    </Fragment>
-</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/BadAttributes.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/BadAttributes.wxs
new file mode 100644
index 00000000..269db3c0
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/BadAttributes.wxs
@@ -0,0 +1,11 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <Feature Id="ProductFeature">
+      <Component Directory="ProgramFilesFolder" Subdirectory="MsiPackage">
+        <File Source="test.txt" Bitness="always64" Condition="BLAHBLAHBLAH" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" />
+      </Component>
+    </Feature>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/ComponentGroup.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/ComponentGroup.wxs
new file mode 100644
index 00000000..69a539a9
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/ComponentGroup.wxs
@@ -0,0 +1,14 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <Feature Id="ProductFeature">
+      <ComponentGroupRef Id="Files" />
+    </Feature>
+    
+    <ComponentGroup Id="Files" Directory="ProgramFilesFolder" Subdirectory="MsiPackage">
+      <File Source="test.txt" />
+      <File Source="test.txt" Name="test2.txt" />
+    </ComponentGroup>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Condition.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Condition.wxs
new file mode 100644
index 00000000..3b5dae22
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Condition.wxs
@@ -0,0 +1,10 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <Feature Id="ProductFeature">
+      <File Id="FILE1" Condition="FILE1" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" />
+      <File Id="FILE2" Condition="FILE2" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" Name="test2.txt" />
+    </Feature>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Directory.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Directory.wxs
new file mode 100644
index 00000000..85cdb029
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Directory.wxs
@@ -0,0 +1,13 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <StandardDirectory Id="ProgramFilesFolder">
+      <Directory Id="INSTALLFOLDER" Name="MsiPackage">
+        <!-- Relies on default-feature feature to include naked files in package. -->
+        <File Id="test.txt" Source="test.txt" />
+        <File Id="test2.txt" Source="test.txt" Name="test2.txt" />
+      </Directory>
+    </StandardDirectory>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/DirectoryRef.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/DirectoryRef.wxs
new file mode 100644
index 00000000..6de50ac4
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/DirectoryRef.wxs
@@ -0,0 +1,17 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <DirectoryRef Id="INSTALLFOLDER">
+      <!-- Relies on default-feature feature to include naked files in package. -->
+      <File Id="test.txt" Source="test.txt" />
+      <File Id="test2.txt" Source="test.txt" Name="test2.txt" />
+    </DirectoryRef>
+  </Package>
+  
+  <Fragment>
+    <StandardDirectory Id="ProgramFilesFolder">
+      <Directory Id="INSTALLFOLDER" Name="MsiPackage" />
+    </StandardDirectory>
+  </Fragment>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Feature.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Feature.wxs
new file mode 100644
index 00000000..d4c2daa9
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Feature.wxs
@@ -0,0 +1,10 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <Feature Id="ProductFeature">
+      <File Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" />
+      <File Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" Name="test2.txt" />
+    </Feature>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/FeatureGroup.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/FeatureGroup.wxs
new file mode 100644
index 00000000..94fdd0de
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/FeatureGroup.wxs
@@ -0,0 +1,22 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <Feature Id="ProductFeature">
+      <FeatureGroupRef Id="ProductFeatureGroup" />
+    </Feature>
+  </Package>
+  
+  <Fragment>
+    <StandardDirectory Id="ProgramFilesFolder">
+      <Directory Id="INSTALLFOLDER" Name="MsiPackage" />
+    </StandardDirectory>
+  </Fragment>
+  
+  <Fragment>
+    <FeatureGroup Id="ProductFeatureGroup">
+      <File Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" />
+      <File Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" Name="test2.txt" />
+    </FeatureGroup>
+  </Fragment>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/FeatureRef.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/FeatureRef.wxs
new file mode 100644
index 00000000..c92db44b
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/FeatureRef.wxs
@@ -0,0 +1,20 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <FeatureRef Id="ProductFeature">
+      <File Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" />
+      <File Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" Name="test2.txt" />
+    </FeatureRef>
+  </Package>
+  
+  <Fragment>
+    <StandardDirectory Id="ProgramFilesFolder">
+      <Directory Id="INSTALLFOLDER" Name="MsiPackage" />
+    </StandardDirectory>
+  </Fragment>
+  
+  <Fragment>
+    <Feature Id="ProductFeature" />
+  </Fragment>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Fragment.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Fragment.wxs
new file mode 100644
index 00000000..6393bbc4
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Fragment.wxs
@@ -0,0 +1,24 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+    <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+        <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+        <FeatureGroupRef Id="FeatureGroup1" />
+        <PropertyRef Id="Property2" />
+    </Package>
+
+    <Fragment>
+        <StandardDirectory Id="ProgramFilesFolder">
+            <Directory Id="INSTALLFOLDER" Name="MsiPackage" />
+        </StandardDirectory>
+    </Fragment>
+
+    <Fragment>
+        <FeatureGroup Id="FeatureGroup1" />
+        <File Id="test.txt" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" />
+    </Fragment>
+
+    <Fragment>
+        <Property Id="Property2" Hidden="yes" />
+        <File Id="test2.txt" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" Name="test2.txt" />
+    </Fragment>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Module.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Module.wxs
new file mode 100644
index 00000000..c94f3720
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Module.wxs
@@ -0,0 +1,6 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Module Id="MergeModule" Guid="e535b765-1019-4a4f-b3ea-ae28870e6d73" Language="1033" Version="1.0.0.0">
+    <File Id="FILE1" Condition="FILE1" Directory="ProgramFilesFolder" Subdirectory="MergeModule" Source="test.txt" />
+    <File Id="FILE2" Condition="FILE2" Directory="ProgramFilesFolder" Subdirectory="MergeModule" Source="test.txt" Name="test2.txt" />
+  </Module>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Package.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Package.wxs
new file mode 100644
index 00000000..e5dd94e0
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/Package.wxs
@@ -0,0 +1,10 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+    <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+        <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+        <File Directory="INSTALLFOLDER" Source="test.txt" />
+        <File Directory="INSTALLFOLDER" Source="test.txt" Name="test2.txt" />
+        <File Directory="INSTALLFOLDER" Source="test.txt" Name="test3.txt" />
+        <File Directory="INSTALLFOLDER" Source="test.txt" Name="test4.txt" />
+    </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/PackageWithDefaultInstallFolder.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/PackageWithDefaultInstallFolder.wxs
new file mode 100644
index 00000000..824f3501
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/PackageWithDefaultInstallFolder.wxs
@@ -0,0 +1,10 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+    <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+        <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+        <File Source="test.txt" />
+        <File Source="test.txt" Name="test2.txt" />
+        <File Source="test.txt" Name="test3.txt" />
+        <File Source="test.txt" Name="test4.txt" />
+    </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/PackageWithoutDefaultFeature.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/PackageWithoutDefaultFeature.wxs
new file mode 100644
index 00000000..0dbf2045
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/PackageWithoutDefaultFeature.wxs
@@ -0,0 +1,17 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+    <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+        <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+        <File Source="test.txt" Name="test3.txt" />
+        <File Source="test.txt" Name="test4.txt" />
+
+        <Feature Id="ProductFeature">
+            <ComponentGroupRef Id="Files" />
+        </Feature>
+
+        <ComponentGroup Id="Files" Directory="ProgramFilesFolder" Subdirectory="MsiPackage">
+            <File Source="test.txt" />
+            <File Source="test.txt" Name="test2.txt" />
+        </ComponentGroup>
+    </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/StandardDirectory.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/StandardDirectory.wxs
new file mode 100644
index 00000000..5b6bdf2f
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/StandardDirectory.wxs
@@ -0,0 +1,11 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <MajorUpgrade DowngradeErrorMessage="Downgrade error message." />
+
+    <StandardDirectory Id="ProgramFilesFolder">
+      <!-- Relies on default-feature feature to include naked files in package. -->
+      <File Id="test.txt" Source="test.txt" />
+      <File Id="test2.txt" Source="test.txt" Name="test2.txt" />
+    </StandardDirectory>
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/WixlibComponentGroup.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/WixlibComponentGroup.wxs
new file mode 100644
index 00000000..90ce0dc9
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/WixlibComponentGroup.wxs
@@ -0,0 +1,8 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+    <Fragment>
+        <ComponentGroup Id="WixlibFiles">
+            <File Id="test.txt" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" />
+            <File Id="test2.txt" Directory="ProgramFilesFolder" Subdirectory="MsiPackage" Source="test.txt" Name="test2.txt" />
+        </ComponentGroup>
+    </Fragment>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/WixlibComponentGroupPackage.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/WixlibComponentGroupPackage.wxs
new file mode 100644
index 00000000..69b92038
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/WixlibComponentGroupPackage.wxs
@@ -0,0 +1,5 @@
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+  <Package Name="MsiPackage" Version="1.0.0.0" Manufacturer="Example Corporation" UpgradeCode="047730a5-30fe-4a62-a520-da9381b8226a">
+    <ComponentGroupRef Id="WixlibFiles" />
+  </Package>
+</Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/test.txt b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/test.txt
new file mode 100644
index 00000000..d32727e0
--- /dev/null
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/NakedFile/test.txt
@@ -0,0 +1 @@
+This is test.txt.
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SingleFile/PackageComponents.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SingleFile/PackageComponents.wxs
index b8e9f59c..488e230f 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SingleFile/PackageComponents.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/SingleFile/PackageComponents.wxs
@@ -2,9 +2,8 @@
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <Fragment>
         <ComponentGroup Id="ProductComponents" Directory="INSTALLFOLDER">
-            <Component>
-                <File Source="test.txt" />
-            </Component>
+            <File Source="test.txt" />
+            
             <Component Id="Shared.dll" Shared="yes">
                 <File Name="Shared.dll" Source="test.txt" />
             </Component>