Lint Hunter: Dictionary of Pain

E0502: Cannot borrow x as mutable because it is also borrowed as immutable

• Cause: You have a reference &x active (an "immutable loan") and you try to do &mut x or modify x.
• Fix 1 (Re-scoping): Use a block {} to force the immutable borrow to drop before the mutation.
• Fix 2 (Cloning): If you need the value for the mutation, clone() the data before taking the mutable borrow.
• Example: let val = x[0].clone(); x.push(val);

E0382: Use of moved value

• Cause: You passed x (by value) to a function or loop, and then tried to use it again.
• Fix 1 (Reference): Pass &x if ownership transfer isn't needed.
• Fix 2 (Clone): If the consumer needs ownership, x.clone().
• Fix 3 (Derive Copy): If the type is trivial (primitive), ensure it derives Copy.

E0597: x does not live long enough

• Cause: You are returning a reference to a local variable that is about to be dropped.
• Fix 1 (Ownership): Return the String (owned), not &str (borrowed).
• Fix 2 (Lifetime Lifting): Declare the storage variable outside the scope where the reference is taken.