Macro qf 

qf!() { /* proc-macro */ }

Qualifies common unqualified standard-library types inside one Rust type.

Nested common types are qualified recursively, while an already qualified path is preserved deliberately.

use these_macros_should_be_illegal::qf;

let value: qf!(Option<Vec<String>>) = Some(vec![String::from("less punctuation")]);
assert!(value.is_some());