Error code E0536
The not cfg-predicate was malformed.
Erroneous code example:
#[cfg(not())] // error: expected 1 cfg-pattern pub fn something() {} pub fn main() {}
The not predicate expects one cfg-pattern. Example:
#[cfg(not(target_os = "linux"))] // ok! pub fn something() {} pub fn main() {}
For more information about the cfg attribute, read the section on
Conditional Compilation in the Reference.