Spurious E0034 for trait methods coming from blanket impl on functions which already have other errors

I tried this code:

#![recursion_limit = "1"]
trait ArgA {}
impl<T> ArgA for (T,) {}
impl ArgA for i32 {}

trait ArgB {}
impl<T> ArgB for (T,) {}
impl ArgB for u8 {}
trait AmbiguousA<Args> {
    fn foo(&self) {}
}
trait AmbiguousB<Args> {
    fn foo(&self) {}
}
impl<Args, F> AmbiguousA<Args> for F
where
    F: Fn(Args),
    Args: ArgA,
{
}
impl<Args, F> AmbiguousB<Args> for F
where
    F: Fn(Args),
    Args: ArgB,
{
}

// broken functions
fn thing(a: ((((((((((i32,),),),),),),),),),)) {}
fn thingb(a: DoesNotExist) {}
fn main() {
    thing.foo();
    thingb.foo();
}

I expected to see this happen: I expected to see recursion depth and E0425 as the sole errors.

Instead, this happened: I got recursion depth, E0425, and E0034 for thing.foo() and thingb.foo() on nightly (next-solver). On stable, thingb throws E0599 instead, but the E0034 for thing is still there.

Note: This was originally noticed in https://github.com/bevyengine/bevy/issues/25511
where there is an additional complication: Its caused by the recursion depth, and when depending on bevy as a library, the recursion depth warnings were hidden, making the E0034 the only visible error.

Meta

rustc --version --verbose:

rustc 1.100.0-nightly (c656540d6 2026-08-21)
binary: rustc
commit-hash: c656540d6467dee1381f0cbd882412d6bd1cd5ae
commit-date: 2026-08-21
host: x86_64-unknown-linux-gnu
release: 1.100.0-nightly
LLVM version: 23.1.0

Start by compiling the supplied reproducer with nightly and the next-solver enabled, comparing the recursion-depth, unresolved-name, and method-call diagnostics. Trace rustc's trait-method lookup and error-reporting path for the two broken functions; done means the spurious E0034 diagnostics are no longer emitted while the expected errors remain.