It's used only as a dev dependency in 12 crates.

Depender (with downloads and own rev deps) smol-macros version
464K 300 smol dev ^0.1.0
18K 15 rustls-acme dev ^0.1.0
900 cast-sender dev ^0.1
180 iocraft dev ^0.1.1
crossmist dev ^0.1
async-nng dev ^0.1
smol-axum dev ^0.1.0
pdf2pwg dev ^0.1
viz-smol dev ^0.1
1 unicom-nres dev ^0.1
unicom-tcp dev ^0.1
vuot dev ^0.1