Compiler error message is confusing

[divinerapier]

I don't know what caused this error. Sorry, I can't provide simple code to reproduce it.

$ rustup show
Default host: x86_64-apple-darwin

installed toolchains
--------------------

stable-x86_64-apple-darwin
nightly-2019-09-13-x86_64-apple-darwin (default)

Thanks.

[csmoe]

Run rustc --explain E0308 as the error said, and you will benefit from reading the book first.

[divinerapier]

@csmoe thank you for your reply. I mean the error message is useless. It says the types mismatched, but there is no context in the error message, so how can I fix it. I know how to fix but I don't know where to fix.

[csmoe]

@divinerapier sorry, reopen.

[divinerapier]

@csmoe thank you very much

[Centril]

Unfortunately, this is report is not actionable without knowing more about the situation, which we will need to know about to fashion a more tailored error message.

[eddyb]

@Centril That's not the problem, the problem is there's no span at all.

@divinerapier Are you using any custom derives? That's the only thing I can think of that could be able to cause this. If you can provide a list of your (proc-macro) dependencies, that could help a lot.

If you want to try to reduce your code, you can start by taking various functions and replacing their bodies with unimplemented!(). If at any point the error goes away, that's the culprit. Otherwise, you can now try to remove various methods and types.

[estebank]

This is a problem that needs to be solved. I'm pretty sure it's a duplicate of #51635.

[divinerapier]

@eddyb When I reduce the code, I find when function_name::named is deleted, the error message will be correct. I hope this will help.

crate function_name