KB171524 - FIX: Ambiguous Names Generate Incorrect Error Message

Article ID: 171524

Article Last Modified on 12/10/2003

Microsoft Visual Basic 5.0 Control Creation Edition
Microsoft Visual Basic 5.0 Learning Edition
Microsoft Visual Basic 5.0 Professional Edition
Microsoft Visual Basic 5.0 Enterprise Edition

This article was previously published under Q171524

SYMPTOMS

If Binary Compatibility is set, then writing a duplicate Implements statement in a Class Module can cause a compatibility error to occur when compiling a DLL, instead of the expected "Ambiguous name detected" error message.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in Visual Studio 97 Service Pack 2.

For more information on the Visual Studio 97 Service Pack 2, please see the following article in the Microsoft Knowledge Base:

170365 INFO: Visual Studio 97 Service Packs - What, Where,and Why

For a list of the Visual Basic 5.0 bugs that were fixed in the Visual Studio 97 Service Pack 2, please see the following article in the Microsoft Knowledge Base:

171554 INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2

MORE INFORMATION

Steps to Reproduce Behavior

NOTE: MSO97.DLL is required to duplicate this scenario.

Start a new ActiveX DLL project in Visual Basic 5.0. Class1 is created by default.
Select Project...References from the menu bar and add a reference to the Microsoft Office 8.0 Object Library.
Select Project...Add Module to add a new Module (Module1).
Add the following code to Module1:
```
      Sub Main()

      End Sub
						
```

Add the following code to Class1:

      Implements IFoundFiles

      Private Property Get IFoundFiles_Count() As Long

      End Property

      Private Property Get IFoundFiles_Item(ByVal Index As Long) As String


      End Property

Select Project...Properties and change the Startup Object to Sub Main.
Select File...Make Project1.dll and compile the project as Project1.DLL.
After compilation, select Project...Project1 Properties, and select Binary Compatibility on the Components tab.

Change the code in Class1 to the following:

      Implements IFoundFiles
      Implements IFoundFiles

      Private Property Get IFoundFiles_Count() As Long

      End Property

      Private Property Get IFoundFiles_Item(ByVal Index As Long) As String

      End Property

Select File...Make Project1.dll, and compile the project as Project2.DLL.

Result

The following Visual Basic dialog box appears:

"The Class1 class implemented an interface in the version-compatible component, but not in the current project.

If you choose Accept, the Class1 class module will no longer support client applications compiled against the version-compatible component. To avoid this incompatibility, add the interface declaration back into the class module, or clear the version compatibility setting in Project Options."

The correct error message that should display is:

"Compile error: Ambiguous name detected: IFoundFiles"

NOTE: This message does display after the initial dialog is dismissed.

NOTE: This behavior has also been reported when duplicate Enum names are used.

Keywords: kbbug kbfix kbvbp500sp2fix kbvs97sp2fix KB171524