Cargo Features

solana-frozen-abi-macro has no features set by default.

[dependencies]
solana-frozen-abi-macro = { version = "2.1.1", features = ["frozen-abi"] }
frozen-abi

activate the frozen-abi feature when we actually want to do frozen-abi testing,
otherwise leave it off because it requires nightly Rust

Affects solana-frozen-abi-macro::derive_abi_sample, solana-frozen-abi-macro::derive_abi_enum_visitor, solana-frozen-abi-macro::frozen_abi