rustc type inference error

errors.txt

     Running `rustc --crate-name core src/lib.rs --crate-type lib --emit=dep-info,link -C debuginfo=2 -C metadata=dc98e8200778de86 -C extra-filename=-dc98e8200778de86 --out-dir /Users/tyler/code/rust/rust-core-template/target/debug/deps -C incremental=/Users/tyler/code/rust/rust-core-template/target/debug/incremental -L dependency=/Users/tyler/code/rust/rust-core-template/target/debug/deps`
error[E0282]: type annotations needed
  --> src/iterator.rs:25:16
   |
25 |         val == LoopState::Continue(())
   |                ^^^^^^^^^^^^^^^^^^^ cannot infer type for `B`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0282`.
error: Could not compile `core`.

iterator.rs

use cmp::*;

enum LoopState<C, B> {
    Continue(C),
    Break(B),
}

#[allow(dead_code)]
impl<C, B> LoopState<C, B> {
    fn my_eq(&self, _other: &Self) -> bool { true }
}

impl<C, B> PartialEq for LoopState<C, B> {
    fn eq(&self, _other: &Self) -> bool { true }
    fn ne(&self, _other: &Self) -> bool { false }
}

pub trait Iterator {
    type Item;

    fn all(&mut self) -> bool
    {
        let val = if false { LoopState::Continue(()) } else { LoopState::Break(()) };
        //val.my_eq(&LoopState::Continue(()))  // this works!
        val == LoopState::Continue(())         // doesn't work when `predicates_of` query is changed
    }
}