4.22.0 release fails to build project with Fulma dependency

[skir]

Description

Hello, I have a project that uses Fable and depends on Fulma for UI rendering.
After I upgraded my Fable version to 4.22.0, my builds started to fail with this error:

.\src\fable_modules\Fulma.3.0.0\Elements\Button.fs(1,1): (1,1) error FSHARP: The module/namespace 'System' from compilation unit 'netstandard' did not contain the namespace, module or type 'ReadOnlySpan`1' (code 193)
.\src\fable_modules\Fulma.3.0.0\Elements\Tag.fs(1,1): (1,1) error FSHARP: The module/namespace 'System' from compilation unit 'netstandard' did not contain the namespace, module or type 'ReadOnlySpan`1' (code 193)

Previously I used 4.19.3 release with no issues. I also tried to build with 4.20.0 and 4.21.0 and got no errors.

Related information

• Fable version: 4.22.0
• Operating system: Windows 10, 22H2

[ncave]

@skir Yes, that seems to be the case when targeting netstandard2.0, not sure why.
As a workaround, you can try targeting net8.0 (or some other TFM), seems to help.