Edited Issue: Designer: Assert throwing when opening the attached edmx as xml [1484]

Following assert is being thrown when I open the edmx as xml

```
---------------------------
Assertion Failed: Abort=Quit, Retry=Debug, Ignore=Continue
---------------------------
Empty span on node



at Microsoft.Data.Tools.XmlDesignerBase.Model.XmlModel.GetXObject(Int32 line, Int32 col)

at Microsoft.Data.Entity.Design.Model.EFArtifact.FindXObjectForLineAndColumn(Int32 lineNumber, Int32 columnNumber)

at Microsoft.Data.Entity.Design.Model.EFArtifact.FindEFObjectForLineAndColumn(Int32 lineNumber, Int32 columnNumber)

at Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.EdmSchemaError2EFObject(EdmSchemaError error, EFArtifact defaultArtifactForError)

at Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ProcessErrors(IEnumerable`1 errors, EntityDesignArtifact defaultArtifactForError, ErrorClass errorClass)

at Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ValidateWithViewGen(StorageMappingItemCollection mappingItemCollection, EntityDesignArtifact designArtifact)

at Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ValidateArtifactSet(EFArtifactSet artifactSet, Boolean force......

<truncated>
---------------------------
Abort Retry Ignore
---------------------------

```


Stack trace:
```
> Microsoft.Data.Tools.Design.XmlCore.dll!Microsoft.Data.Tools.XmlDesignerBase.Model.XmlModel.GetXObject(int line, int col) Line 224 C#
Microsoft.Data.Tools.Design.XmlCore.dll!Microsoft.Data.Entity.Design.Model.EFArtifact.FindXObjectForLineAndColumn(int lineNumber, int columnNumber) Line 911 C#
Microsoft.Data.Tools.Design.XmlCore.dll!Microsoft.Data.Entity.Design.Model.EFArtifact.FindEFObjectForLineAndColumn(int lineNumber, int columnNumber) Line 917 C#
Microsoft.Data.Entity.Design.Model.dll!Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.EdmSchemaError2EFObject(System.Data.Entity.Core.Metadata.Edm.EdmSchemaError error, Microsoft.Data.Entity.Design.Model.EFArtifact defaultArtifactForError) Line 340 C#
Microsoft.Data.Entity.Design.Model.dll!Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ProcessErrors(System.Collections.Generic.IEnumerable<System.Data.Entity.Core.Metadata.Edm.EdmSchemaError> errors, Microsoft.Data.Entity.Design.Model.EntityDesignArtifact defaultArtifactForError, Microsoft.Data.Entity.Design.Model.Validation.ErrorClass errorClass) Line 264 C#
Microsoft.Data.Entity.Design.Model.dll!Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ValidateWithViewGen(System.Data.Entity.Core.Mapping.StorageMappingItemCollection mappingItemCollection, Microsoft.Data.Entity.Design.Model.EntityDesignArtifact designArtifact) Line 251 C#
Microsoft.Data.Entity.Design.Model.dll!Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ValidateArtifactSet(Microsoft.Data.Entity.Design.Model.EFArtifactSet artifactSet, bool forceValidation, bool validateMsl, bool runViewGen) Line 90 C#
Microsoft.Data.Entity.Design.Model.dll!Microsoft.Data.Entity.Design.Model.Validation.RuntimeMetadataValidator.ValidateAndCompileMappings(Microsoft.Data.Entity.Design.Model.EFArtifactSet artifactSet, bool validateMapping) Line 54 C#
Microsoft.Data.Entity.Design.Model.dll!Microsoft.Data.Entity.Design.Model.EntityDesignModelManager.ValidateAndCompileMappings(Microsoft.Data.Entity.Design.Model.EntityDesignArtifactSet artifactSet, bool doEscherValidation) Line 96 C#
Microsoft.Data.Entity.Design.dll!Microsoft.Data.Entity.Design.VisualStudio.VisualStudioEdmxValidator.ValidateArtifactAndWriteErrors(Microsoft.Data.Entity.Design.Model.EFArtifact artifact, Microsoft.VisualStudio.Shell.Interop.IVsHierarchy hierarchy, uint itemId, bool doEscherValidation) Line 127 C#
Microsoft.Data.Entity.Design.dll!Microsoft.Data.Entity.Design.VisualStudio.VisualStudioEdmxValidator.ValidateArtifactAndWriteErrors(Microsoft.Data.Entity.Design.Model.EFArtifact artifact, Microsoft.Data.Entity.Design.VisualStudio.VSFileFinder.VSFileInfo vsFileInfo, bool doEscherValidation) Line 107 C#
Microsoft.Data.Entity.Design.dll!Microsoft.Data.Entity.Design.VisualStudio.VisualStudioEdmxValidator.LoadAndValidateFiles(System.Collections.Generic.IEnumerable<Microsoft.Data.Entity.Design.VisualStudio.VSFileFinder.VSFileInfo> edmxFilesToValidate, bool doEscherValidation, System.Func<Microsoft.Data.Entity.Design.Model.EFArtifact,bool> shouldValidateArtifact) Line 80 C#
Microsoft.Data.Entity.Design.dll!Microsoft.Data.Entity.Design.VisualStudio.VisualStudioEdmxValidator.LoadAndValidateFiles(System.Uri[] uris) Line 60 C#
Microsoft.Data.Entity.Design.dll!Microsoft.Data.Entity.Design.VisualStudio.Package.EntityDesignDocumentFrameMgr.OnBeforeDocumentWindowShow(uint docCookie, int fFirstShow, Microsoft.VisualStudio.Shell.Interop.IVsWindowFrame pFrame) Line 124 C#

```

After ignoring the assert when the edmx finally opens, this error msg is shown.

```
Error 1 Error 3004: Problem in mapping fragments starting at line -1:No mapping specified for properties Entity2.ComplexProperty1 in Set Entity2.
An Entity with Key (PK) will not round-trip when:
Entity is type [Model1.Entity2]
c:\users\mugdhak\documents\visual studio 2013\Projects\ConsoleApplication26\ConsoleApplication26\Model1.edmx 1 1 ConsoleApplication26

```