Meaningless exceptions

[zorgoz]

Describe the bug
I am migrating my API from .net framework 4.6 to .net 9. I might have missed something, as I get an exception when trying to generate the API documentation. But the exception is terribly useless:

Expected behavior
I would love to see which HTTP method is that, and, at least, which controller and which action method, so I can go and fix it. Right now this exception doesn't provide any information whatsoever. A code analyzer could also be helpful.

Additional context
I am using controllers, not minimal API. I wanted to try the build time generator, but that failed on the msbuild task itself by missing some parameters. But that requires a separate issue.

[zorgoz]

I found it: in the old WebApi the [Route("path")] attribute on an action method defaulted to HttpGet. I have missed some. But that doesn't change the issue.