Invalid help message when traits in #[derive()] miss type annotation

[yshui]

#[derive(Serialize, Deserialize)]
struct Container<T: Serialize + Deserialize> {
	data: T
}

Which gives me this error message:

error[E0283]: type annotations needed
  --> src/main.rs:33:21
   |
33 | #[derive(Serialize, Deserialize)]
   |                     ^^^^^^^^^^^ cannot infer type for type parameter `T`
34 | struct Container<T: Serialize + Deserialize> {
   |                                 ----------- required by this bound in `Container`
   |
   = note: cannot satisfy `T: _::_serde::Deserialize<'static>`
   = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider specifying the type argument in the function call
   |
33 | #[derive(Serialize, Deserialize::<T>)]

Which suggests invalid modification.

rustc --version --verbose:

rustc 1.47.0-nightly (09f4c9f50 2020-08-07)
binary: rustc
commit-hash: 09f4c9f5082f78b0adcee83d3ab4337e000cd28e
commit-date: 2020-08-07
host: x86_64-unknown-linux-gnu
release: 1.47.0-nightly
LLVM version: 10.0

[eggyal]

This invalid error doesn't really have anything to do with #[derive()]—it also occurs in the expanded code.

MCVE:

trait Deserialize<'de> {
    fn deserialize();
}

struct Container<T: Deserialize> {
    data: T
}

impl <'de, T: Deserialize> Deserialize<'de> for Container<T> where T: Deserialize<'de> {
    fn deserialize() { 
        loop {}
    } 
}

includes the error

error[E0283]: type annotations needed
 --> src/main.rs:9:15
  |
1 | trait Deserialize<'de> {
  | ---------------------- required by this bound in `Deserialize`
...
9 | impl <'de, T: Deserialize> Deserialize<'de> for Container<T> where T: Deserialize<'de> {
  |               ^^^^^^^^^^^ cannot infer type for type parameter `T`
  |
  = note: cannot satisfy `T: Deserialize<'static>`
help: consider specifying the type arguments in the function call
  |
9 | impl <'de, T: Deserialize::<Self, 'de>> Deserialize<'de> for Container<T> where T: Deserialize<'de> {
  |                          ^^^^^^^^^^^^^

[yshui]

Right, but the suggested change is invalid because of derive()

[eggyal]

The suggested change in the expanded version is also invalid.