Crossgen2 does not work with PublishReadyToRunEmitSymbols

[AntonLapounov]

Specifying both PublishReadyToRunEmitSymbols and PublishReadyToRunUseCrossgen2 properties leads to PDB generation failures during the _CreateR2RSymbols target (composite mode only).

Repro steps:

dotnet new console
dotnet publish -r win-x64 /p:PublishReadyToRunEmitSymbols=true /p:PublishReadyToRun=true /p:PublishReadyToRunUseCrossgen2=true

Output:

error : Error generating PDB for 'obj\Debug\net5.0\win-x64\R2R\foo.dll': Index not found. (0x80131124)
error : Error: compilation failed for "obj\Debug\net5.0\win-x64\R2R\foo.dll" (0x80131124)
error : Error generating PDB for 'obj\Debug\net5.0\win-x64\R2R\Microsoft.CSharp.dll': Index not found. (0x80131124)
error : Error: compilation failed for "obj\Debug\net5.0\win-x64\R2R\Microsoft.CSharp.dll" (0x80131124)
error : Error generating PDB for 'obj\Debug\net5.0\win-x64\R2R\Microsoft.VisualBasic.Core.dll': Index not found. (0x80131124)
error : Error: compilation failed for "obj\Debug\net5.0\win-x64\R2R\Microsoft.VisualBasic.Core.dll" (0x80131124)
...

@davidwrighton @mangod9

[davidwrighton]

We won't be fixing this in .NET 5.

[trylek]

@davidwrighton - is this a deficiency of the PDB generator so that we should track fixing it for the .NET 6 release?

[trylek]

@AntonLapounov - I believe this should be now fixed with SDK Preview 2 including my change

dotnet/sdk#15529

where we newly use Crossgen2 to emit PDB directly during compilation, not during the separate _CreateR2RSymbols target. Do you think we can close this issue?

[AntonLapounov]

Verified as fixed in .NET 6 SDK. When targeting .NET 6, the PDB is successfully generated. When targeting .NET 5, the following error is reported:

error NETSDK1163: Cannot emit symbols when publishing for .NET 5 with Crossgen2 using composite mode.