Lint suggestion: Unnecessary Debug bound

Hi,

for some reason I believed that #[derive(Debug)] requires all fields of a struct to implement Debug. Thus, I wrote code like the following:

#[derive(Debug)]
pub struct Example<T: Debug> {
    inner: T
}

However, since then I learned that #[derive(Debug)] generates the appropriate code that Example<T> only implements Debug when T: Debug. Thus, my Debug bound was completely unnecessary.

I am not sure if this is worth turning into a new lint. If you think not, then feel free to just close this issue.

Thanks for clippy!

The issue names no implementation files or tests. Start by locating Clippy's existing lints for redundant generic trait bounds and their test coverage, then verify how a bound such as T: Debug interacts with a derived Debug implementation. Done means the unnecessary-bound pattern is detected without flagging required bounds, with regression coverage added.