unconstrained associated type in `param_env` results in ICE

trait MyFnOnce: FnOnce() -> Self::Ret {
    type Ret;
}
impl<F: FnOnce() -> R, R> MyFnOnce for F {
    type Ret = R;
}

trait FnOnceWhichOutputs<R>: MyFnOnce<Ret = R> {}
impl<R, F: FnOnce() -> R> FnOnceWhichOutputs<R> for F {}

fn ice_ice_baby<F: for<'any> FnOnceWhichOutputs<&'any str>>() {}

The following ICEs in fn normalize_param_env_or_error with

error: internal compiler error: `[Binder { value: TraitPredicate(<F as FnOnceWhichOutputs<&'any str>>, polarity:Positive), bound_vars: [Region(BrNamed(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)))] }, Binder { value: ProjectionPredicate(AliasTerm { args: [F/#0], def_id: DefId(0:4 ~ playground[dcd1]::MyFnOnce::Ret), .. }, Term::Ty(&'^0.Named(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)) str)), bound_vars: [Region(BrNamed(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)))] }, Binder { value: TraitPredicate(<F as MyFnOnce>, polarity:Positive), bound_vars: [Region(BrNamed(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)))] }, Binder { value: ProjectionPredicate(AliasTerm { args: [F/#0, ()], def_id: DefId(2:3993 ~ core[2e27]::ops::function::FnOnce::Output), .. }, Term::Ty(&'?0 str)), bound_vars: [Region(BrNamed(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)))] }, Binder { value: TraitPredicate(<F as std::ops::FnOnce<()>>, polarity:Positive), bound_vars: [Region(BrNamed(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)))] }, Binder { value: TraitPredicate(<F as std::marker::MetaSized>, polarity:Positive), bound_vars: [Region(BrNamed(DefId(0:16 ~ playground[dcd1]::ice_ice_baby::'any)))] }, Binder { value: TraitPredicate(<F as std::marker::Sized>, polarity:Positive), bound_vars: [] }]` is not fully resolved
  |
  = note: delayed at /rustc-dev/ded5c06cf21d2b93bffd5d884aa6e96934ee4234/compiler/rustc_infer/src/infer/mod.rs:1260:43 - disabled backtrace

Discovered by @danielhenrymantilla (https://github.com/rust-lang/rust/issues/141713#issuecomment-3769164441) and further minimized by @maxdexh (https://github.com/rust-lang/rust/issues/141713#issuecomment-3769230685). cc @theemathas

Start by reproducing the minimized Rust example and reading fn normalize_param_env_or_error in compiler/rustc_infer/src/infer/mod.rs around line 1260. Trace how the unconstrained associated type enters the param environment and verify that the reproducer no longer triggers an internal compiler error, with regression coverage for this case.