MultiIndex prefix and sub_prefix working incorrectly when using a triple element tuple as IK

[y-pakorn]

Current prefix and sub_prefix of MultiIndex don't correctly use Prefix and SubPrefix type bound, resulting in unexpected behavior when using struct that utilize all of prefix, sub prefix, suffix, super suffix. For example, triple element tuple.

let f: MultiIndex<(u32, u64, u128), (u32, u64, u128), u128> =
    MultiIndex::new(|e| (e.0, e.1, e.2), "pk", "idx");

f.prefix((1, 2)); // expected tuple `(u32, u64, u128)` found tuple `(u32, u64)`
f.sub_prefix(1u32); //  expected tuple `(u32, u64)` found type `u32`

Original interface

pub fn prefix(&self, p: IK) -> Prefix<PK, T, PK>;
pub fn sub_prefix(&self, p: IK::Prefix) -> Prefix<PK, T, (IK::Suffix, PK)>;

Correct Interface

pub fn prefix(&self, p: IK::Prefix) -> Prefix<PK, T, (IK::Suffix, PK)>;
pub fn sub_prefix(&self, p: IK::SubPrefix) -> Prefix<PK, T, (IK::SuperSuffix, PK)>;

[y-pakorn]

Sorry, misunderstanding, working as expected now.