Type inference failure when f64 ops are not explicitly stated

[attack68]

I tried this code:

use std::ops::Add;

fn some_op<T>(a: &f64, b: &T) -> T
where
    for <'a> &'a f64: Add<&'a T, Output = T>
    {
        let t = 2.5_f64;
        &(a + &t) + b
    }

#[derive(Debug)]
struct MyStruct {
    val: f64
}

impl Add<&MyStruct> for &f64 {
    type Output = MyStruct;
    fn add(self, other: &MyStruct) -> MyStruct {
        MyStruct {val: self + other.val}
    }
}

fn main() {
    let a = 1.5_f64;
    let b = MyStruct{val: 3.5_f64};
    println!("{:?}", some_op(&a, &b));
}

This code is valid due to the implementation of Add<&f64> for &f64 in the standard library.
The compiler reports this error:

error[E0308]: mismatched types
 --> src/main.rs:8:15
  |
3 | fn some_op<T>(a: &f64, b: &T) -> T
  |            - expected this type parameter
...
8 |         &(a + &t) + b
  |               ^^ expected `&T`, found `&f64`
  |
  = note: expected reference `&T`
             found reference `&f64`

error[E0369]: cannot add `&T` to `&T`
 --> src/main.rs:8:19
  |
8 |         &(a + &t) + b
  |         --------- ^ - &T
  |         |
  |         &T
  |
help: consider extending the `where` clause, but there might be an alternative better way to express this requirement
  |
5 |     for <'a> &'a f64: Add<&'a T, Output = T>, &T: Add<&T, Output = T>
  |                                             +++++++++++++++++++++++++

The expected type is not necessary and E0308 should not appear and finding f64 is correct.
If the following bound is added the code compiles without issue:

fn some_op<T>(a: &f64, b: &T) -> T
where
    for <'a> &'a f64: Add<&'a T, Output = T> + Add<&'a f64, Output = f64>

Meta

rustc --version --verbose:

1.76.0
Also tested nightly. 1.78.0

[veera-sivarajan]

@rustbot claim

[veera-sivarajan]

Looks like this is a duplicate of #24066.