Repository: rust
Issue: Recursive rustc error not solved by #89576  - error[E0275]: overflow evaluating the requirement `&HashSet<_, _>: std::ops::Sub`
Labels: A-diagnostics,T-compiler,D-confusing,D-newcomer-roadblock

Im still getting a recursion error even after #89576.
Maybe related: #77291, #89576, #75397.

I tried this code:

```rust
pub async fn products( params: Query<QueryParams>, Extension(pool): Extension<Pool<Postgres>>)
                       -> impl IntoResponse {
    async move {
        let mut connection=pool.acquire().await.unwrap();

        connection.transaction(|conn| async move {
            let products: Pin<Box<dyn futures::Stream<Item=Result<Bytes, sqlx::Error>> + Send>> = query_as!(
        Product,
        "select * from products order by product_name")
                .map(|p| {
                    let json = format!("{}\n", serde_json::to_string(&p).unwrap());
                    Bytes::from(json)
                })
                .fetch(&mut connection);
            Ok(StreamBody::new(products))
        })
    }.await
}

#[derive(Debug,Serialize, Deserialize, ormx::Table, sqlx::FromRow)]
#[ormx(table = "Products", id = product_id, insertable, deletable)]
struct Product {
    product_id: i16,
    product_name: String,
    supplier_id: i16,
    category_id: i16,
    quantity_per_unit: String,
    unit_price: f32,
    units_in_stock: i16,
    units_on_order: i16,
    reorder_level: i16,
    discontinued: i32,
}
```
I know there is an error in the code I meant to put `conn` where it is presently `.fetch(&mut connection)`.

I expected to see this happen: A non-recursive compiler error.

Instead, this happened (`cargo +nightly build`):

```
error[E0275]: overflow evaluating the requirement `&HashSet<_, _>: std::ops::Sub`
   --> src/northwind.rs:92:39
    |
92  |           connection.transaction(|conn| async move {
    |  _______________________________________^
93  | |             let products: Pin<Box<dyn futures::Stream<Item=Result<Bytes, sqlx::Error>> + Send>> = query_as!(
94  | |         Product,
95  | |         "select * from products order by product_name")
...   |
101 | |             Ok(StreamBody::new(products))
102 | |         })
    | |_________^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`server`)
    = note: required because of the requirements on the impl of `std::ops::Sub` for `&ordered_float::OrderedFloat<HashSet<_, _>>`
    = note: 126 redundant requirements hidden
    = note: required because of the requirements on the impl of `std::ops::Sub<&ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::OrderedFloat<ordered_float::....etc
```

`rustc --version --verbose`:

```
rustc 1.58.0-nightly (547a6ffee 2021-10-21)
binary: rustc
commit-hash: 547a6ffee0cf4da9929a9e3d49546dc87d607735
commit-date: 2021-10-21
host: x86_64-unknown-linux-gnu
release: 1.58.0-nightly
LLVM version: 13.0.0

cargo --version --verbose
cargo 1.57.0-nightly (7fbbf4e8f 2021-10-19)
release: 1.57.0
commit-hash: 7fbbf4e8f23e3c24b8afff541dcb17e53eb5ff88
commit-date: 2021-10-19
host: x86_64-unknown-linux-gnu
libgit2: 1.3.0 (sys:0.13.23 vendored)
libcurl: 7.79.1-DEV (sys:0.4.49+curl-7.79.1 vendored ssl:OpenSSL/1.1.1l)
os: Ubuntu 20.04 (focal) [64-bit]
```

Another version of the code compiles and works fine 

```rust
pub async fn products_via_vec( params: Query<QueryParams>, Extension(pool): Extension<Pool<Postgres>>)
    -> impl IntoResponse {

    let products:Vec<Result<_, std::io::Error>>=query_as!(
        Product,
        "select * from products order by product_name")
            .map(|p| {
                let json=format!("{}\n",serde_json::to_string(&p).unwrap());
                Ok(Bytes::from(json)) })
            .fetch_all(&pool).await.unwrap();

    let stream = stream::iter(products);
    StreamBody::new(stream)
}
```

Im not sure how to create a minimal test case of what is occurring.
I can provide the cargo toml if required