Can't use transparent type in a postgres ANY array

[carols10cents]

What happened

I have a type that wraps a primitive type that is annotated with #[sqlx(transparent)], much like this one in the test suite:

#[sqlx(transparent)]
struct Transparent(i32);

I have a &[Transparent] that I want to be able to use in a query like SELECT ... WHERE something IN ($1) with $1 bound to my slice of Transparent values.

Per the relevant FAQ entry, I tried:

sqlx::query("SELECT ... WHERE something = ANY($1);")
    .bind(values) // values is &[Transparent]

but compiling this gives me the error the trait `PgHasArrayType` is not implemented for `Transparent`.

Interestingly, if I map out the inner primitive value by doing something like:

let primitive_values: Vec<_> = values.iter().map(|v| v.0).collect();
sqlx::query("SELECT ... WHERE something = ANY($1);")
    .bind(&primitive_values) // primitive_values is &[i32]

then I don't get the compiler error.

I expected both of these to compile and function in the same way.

I've tried to make a minimal test case in this PR I made to my own fork so that I could demonstrate the compiler error happens in CI.

I'm happy to submit that test case as a PR here if it's useful, but I wasn't sure enough that this use case is supported or that I'm doing what I'm supposed to be doing.

Thanks!

[jplatte]

This should work if you manually implement PgHasArrayType for Transparent in terms of i32s PgHasArrayType implementation.

I think there's another issue somewhere about basically the same thing for custom enum types. This is just a matter of nobody having put in the work to derive that trait yet.