Compilation error when trying to use palette

[NeverGivinUp]

When adding any use statement from my local palette crate to my library -- I have not tried using the official version -- I get the following error:

error[E0275]: overflow evaluating the requirement `f64: std::ops::Div<palette::blend::PreAlpha<_>>`
  --> src\text.rs:35:50
   |
35 |         let centering_height_shift = self.height / 2.0;
   |                                                  ^
   |
   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`web_utils`)
   = note: required because of the requirements on the impl of `std::ops::Div<palette::blend::PreAlpha<palette::blend::PreAlpha<_>>>` for `f64`
   = note: 127 redundant requirements hidden
   = note: required because of the requirements on the impl of `std::ops::Div<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<palette::blend::PreAlpha<_>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` for `f64`

The error goes away, when I comment out the line
impl_scalar_binop!(Div::div, DivAssign::div_assign, [f32, f64]);

I believe is unrelated to my local changes and it certainly is unrelated to the code, where the error occurs. It may be related to a bug in the rust compiler.

[Ogeon]

I had similar errors that came and went away but I don't remember how I fixed it last time.

Which compiler version are you using? Does it change if you switch to another version?

[NeverGivinUp]

I updated to the current nightly during our conversation on the weekend. My code unfortunately requires associated type bounds and does not compile with the stable compiler. How do I use an older nightly compiler?

[Ogeon]

I see, then it's trickier to test with something stable unless it can be minimized into an example without them.

I'm not sure off the top of my head but you may be able to pick the nightly version with rustup.

[NeverGivinUp]

Using an old nightly (in this case the one from 2022-01-01) didn't help. Neither did replacing the division by 2 by a multiplication by 0.5. This was the only line, the compiler didn't like, though. And extreme disambiguation did help

let centering_height_shift = <f64 as Div>::div(self.height, 2.0);

[Ogeon]

What if you write self.height / 2.0f64? Does it still complain?

[Ogeon]

I'm reopening this because there may be something that can mitigate the issue.

[NeverGivinUp]

What if you write self.height / 2.0f64? Does it still complain?

Yes.
Also if I create a separate variable with explicit type

let h: f64 = self.height;
h/2.0_f64

Still does not work

[NeverGivinUp]

I'm reopening this because there may be something that can mitigate the issue.

There is an answer in the StackOverflow post, which I originally linked, which seems to contain 2 workarounds. But I didn't read them properly.

[Ogeon]

Ah, so something about how it transforms the division into a function call is getting stuck. It would be nice to have a small test case to keep here and also find out which implementation is the problematic one.

Would you mind sharing the full code or try to reduce it into a minimal test case?

[Ogeon]

I'll have a look at those workarounds later and see if they could help too. Thanks for pointing them out!

[NeverGivinUp]

https://github.com/NeverGivinUp/palette_compilation_rest.git

(was meant to be a compilation test, not a rest)

[Ogeon]

Perfect, thanks! 🙏

[TiemenSch]

This just started hitting my code today. Any multiplication with two f64's trips up one by one. I can't go change all these lines to the ::mul(self, rhs) format, since that would be silly. What would you recommend to do?