Proposal: Add switch for treating nullable-related warnings as errors

[hez2010]

Version Used: .NET 5 Preview 4

If I want to treat all nullable-related warnings as errors, I have to treat CS8597 to CS8714 which declared in

roslyn/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

Line 1639 in 3c1c0fc

WRN_ThrowPossibleNull = 8597,

as error in .csproj file manually, and it's really inconvenient.

I hope that there can have a switch to treat all nullable-related warnings as errors.

For example:

<PropertyGroup>
  <TreatNullableWarningAsError>true</TreatNullableWarningAsError>
</PropertyGroup>

[jcouv]

There is already a compiler option to do this: -warnaserror: nullable from the command-line.
It should also work by passing "nullable" (in place of a specific diagnostic ID) to the "TreatWarningsAsErrors" "WarningsAsErrors" msbuild option.
<WarningsAsErrors>nullable</WarningsAsErrors>

I'll go ahead and close this issue as fixed. Thanks

[hez2010]

It works while building the project, but Visual Studio doesn't respect it and still produce warnings.

[jcouv]

@hez2010 Indeed. Filed #52407 an issue (WarningsAsErrors should be honored in IDE too).

[hez2010]

Thanks!