I cloned fresh https://github.com/substrate-developer-hub/substrate-node-template repository (sometime ago it was working fine) I have executed:
cargo build --release
and got:
And many, many more errors while compiling. How to cope with that? Any ideas?
I (thanks to Dan) solved it by execution:
rustup update nightly
rustup update stable
// and then
cargo build --release
And works!