Cargo Features

[dependencies]
core2 = { version = "0.4.0", default-features = false, features = ["std", "alloc", "nightly"] }
default = std

The std feature is set by default whenever core2 is added without default-features = false somewhere in the dependency tree.

std default = alloc
alloc std

Affects traits::Read.read_to_end

nightly

Affects util::copy