You are working in a .net Core or .net Standard codebase and get the error „Missing compiler required member ‚Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create“. In my case it appears when I used the dynamic type. The solution is to load the nuget package Microsoft.CSharp. After you installed it and write a using to your code everything should work as expected.
SPFx Webpart – Gulp error | Primordials is not defined
If you get the error primordials is not defined while calling a gulp command in command line the following might be the solution.
Go to your package.json file and in the node resolutions add an element graceful-fs with the LTS version in my case it was ^4.2.4. If you have Yarn installed you can now call yarn install and the dependencies are updated. When you now run the gulp command again the error could be gone.