Upgraded to Dotnet Core 3.1 from 2.2, EF core kept complaining EF1001: internal ef core api usage by putting an Exclamation Mark in my project.
But no error / warning shown during compilation. I do not know which line of code is causing the trouble.
May I know how can I find out which API / Method that I am not suppose to use?
The warnings from these analyzers can be really confusing. If I understand this correctly, the issue is not what it seems.
The message with the gray warning icon inside the analyzer is normal and indicates what the analyzer is checking. See the Analyzers in Solution Explorer documentation for an explanation.
If you are experiencing yellow icons on the parent node ("Analyzers") try to unload/reload the project, or maybe open Visual Studio in admin mode. See the answer to "Analyzers warnings in ASP.NET Core 2.2 project in VS2019 " for details.
If you don't see a warning in the error list then I advise you to ignore that.
The GitHub issue "Confusing analyzer warnings in solution explorer with no way to see any details" provides additional information on this.