gistfile1.txt

// Instance coherence enforcement should forbid this situation

mod C1 {
    trait C1Trait { }
}

mod C2 {
    type C2Type = int;
}

mod C3 {
    import C1;
    import C2;
    
    // conflicts with potential other impls
    impl of C1Trait for C2Type { } 
}

// But this should be OK:

mod C3v2 {
    import C1;
    import C2;
    
    enum local_myType = myType;
    impl of C1Trait for local_myType { }
}

// As should this:

mod C1v2 {
    import C2;

    trait C1Trait { }
    impl of C1Trait for C2Type { }
}

mod C3v2 {
    import C1v2; // imports the trait as well as its impl
}

mod C4 {
    import C1v2; // imports the trait as well as its impl
}