Generator 'SourceGenerator' failed to generate source.

[L00pZBreak3r]

Actual behavior

Generator 'SourceGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'An item with the same key has already been added.'

Expected behavior

Successful compilation.

Repro steps

1. NativeMethods.txt content:

CLSCTX
CoCreateInstance
CoTaskMemFree
ISpellChecker
ISpellCheckerFactory
S_FALSE
S_OK
SpellCheckerFactory

2. NativeMethods.json content (if present):

{
  "$schema": "..\\..\\src\\Microsoft.Windows.CsWin32\\settings.schema.json"
}

3. Any of your own code that should be shared?

Context

• CsWin32 version: 0.2.206-beta
• Win32Metadata version (if explicitly set by project): 49.0.21-preview
• Target Framework: netstandard2.0
• LangVersion (if explicitly set by project): [e.g. 9]

[Marlax0]

I had the same problem when I added the Microsoft.Windows.SDK.Win32Metadata package (49.0.21-preview) to my project.
Removing it allowed the source generator to work again.

Not sure what the issue is.

[AArnott]

Each major version update of metadata carries with it the potential to break the source generator. We need a source generator update to get you to the latest metadata, evidently.