Specialization impl does not specialize any associated items

Question

I'm fairly new to Rust and ink! itself.

I'm trying to compile and build an extremely basic PSP22 Contract.

I get the following error when I compile & build:

(running cargo +nightly contract build)

The following is my Contract (lib.rs) :

#![cfg_attr(not(feature = "std"), no_std)]
#![feature(min_specialization)]
        
#[openbrush::contract]
pub mod my_psp22 {
    
    // imports from openbrush
    use openbrush::contracts::psp22::*;
    use openbrush::traits::Storage;

    #[ink(storage)]
    #[derive(Default, Storage)]
    pub struct Ipsp22 {
        #[storage_field]
        psp22: psp22::Data,
    }
    
    // Section contains default implementation without any modifications
    impl PSP22 for Ipsp22 {}
     
    impl Ipsp22 {
        #[ink(constructor)]
        pub fn new(initial_supply: Balance) -> Self {
            let mut _instance = Self::default();
            _instance._mint_to(_instance.env().caller(), initial_supply).expect("Should mint"); 
            _instance
        }
    }
}

And here is my Cargo.toml :

[package]
name = "my_token"
version = "0.1.0"
authors = ["0xD1x0n"]
edition = "2021"
license = "Apache 2.0"

[dependencies]
ink = { version = "~4.0.0", default-features = false }
openbrush = { git = "https://github.com/727-Ventures/openbrush-contracts/", tag = "3.0.0", default-features = false, features = ["psp22", "ownable"] }

scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["derive"] }
scale-info = { version = "2.3", default-features = false, features = ["derive"], optional = true }

[lib]
name = "my_token"
path = "lib.rs"
crate-type = [
    "cdylib",
    "rlib",
]

[features]
default = ["std"]
std = [
    "ink/std",
    "scale/std",
    "scale-info/std",
    "openbrush/std",
]
ink-as-dependency = []

I am using the following versions of these tools:

• rustc 1.69.0 (84c898d65 2023-04-16)
• cargo-contract-contract 2.2.1-91b5a86-aarch64-apple-darwin
• rustup 1.26.0 (5af9b9484 2023-04-05)

I'm not quite sure why its happening, any help would be deeply appreciated

Answer 1

I made these changes to your code and it compiled successfully:

I was using these versions:

rustc 1.69.0 (84c898d65 2023-04-16)
cargo-contract-contract 3.0.1-unknown-x86_64-unknown-linux-gnu
rustup 1.26.0 (5af9b9484 2023-04-05)

I was running it in a Docker container running:

Debian GNU/Linux 11 (bullseye)

I ran it with the following and it worked:

cargo +nightly-2023-03-21-x86_64-unknown-linux-gnu contract build

Answer 2

Resolved by using this as my Cargo.toml :

[package]
name = "alephcontract"
version = "1.0.0"
edition = "2021"
authors = ["0xD1x0n"]

[dependencies]
ink = { version = "4.2.1", default-features = false }
scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["derive"] }
scale-info = { version = "2.3", default-features = false, features = ["derive"], optional = true }

openbrush = { git = "https://github.com/727-Ventures/openbrush-contracts", tag = "3.1.0", default-features = false, features = ["psp22","ownable",]}

[lib]
name = "alephcontract"
path = "lib.rs"
crate-type = [
    # Used for normal contract Wasm blobs.
    "cdylib",
    "rlib",
]

[features]
default = ["std"]
std = [
    "ink/std",
    "scale/std",
    "scale-info/std",
    "openbrush/std",
]

psp22 = ["openbrush/psp22"]
ink-as-dependency = []

I compiled the contract using toolchain +nightly-2023-01-01 by executing the following command :

cargo +nightly-2023-01-01 contract build --release