Suggest a code fix when an attribute macro is incorrectly used as a derive macro

[LukeMathWalker]

Code

#[proc_macro_attribute]
pub fn attribute_macro(_metadata: TokenStream, input: TokenStream) -> TokenStream {
    input
}

Current output

error: expected derive macro, found attribute macro `my_macro::attribute_macro`
  |
1 | #[derive(my_macro::attribute_macro)]
  |          ^^^^^^^^^^^^^^^^^^^^^^^^^ not a derive macro

Desired output

(The actual desired output should have colours and minuses on the removed derive, but to give the idea)

error: expected derive macro, found attribute macro `my_macro::attribute_macro`
  |
1 | #[derive(my_macro::attribute_macro)]
  |          ^^^^^^^^^^^^^^^^^^^^^^^^^ not a derive macro
  = help: remove the "derive":

  #[my_macro::attribute_macro]

Rationale and extra context

Many users are not familiar with the terminology being used by the compiler error (i.e. the different flavours of procedural macro, derive vs attribute) and might be confused as to what they need to do in order to fix the error.
Since the fix is straight-forward (i.e. remove the derive), the compiler should show a code snippet that fixes the issue.

Other cases

No response

Anything else?

No response

[NotStirred]

@rustbot claim

[NotStirred]

I have a partially functional implementation of this, though I've run into a bit of trouble, some guidance would be appreciated.

Currently I'm implementing this next to the existing error in compiler/rustc_resolve/src/macros.rs in Resolver#smart_resolve_macro_path.

My trouble comes with knowing what the macro is invoked on, (function, struct), and sending the help message selectively based on that. Is there a way to get this information in smart_resolve_macro_path, or is my approach wrong and the error should be elsewhere?

As far as I can tell I am trying to implement this in a place before the AST is fully parsed, so this may be unviable