Fix E0713: Borrowed data escapes beyond mutable reference

Mon, 06 Jul 2026 15:08:04 +0800

1. Symptoms

When you encounter Rust compiler error E0713, the compiler produces output similar to the following:

error[E0713]: borrowed data escapes beyond mutable reference
  --> src/main.rs:12:9
   |
12 |     let value = do_something(&mut x);
   |                 ^^^^^^^^^^^^^^^^^ borrowed data escapes beyond mutable reference
   |
   = note: this is a special case of borrowed pointer being returned where the lifetime of the pointer is tied to the mutable reference. This typically happens when a closure captures a reference that must outlive the containing function.
help: consider changing the return type to capture the data with a higher lifetime
   |
   = note: the lifetime from the mutable reference is only valid within the containing function. To fix this, ensure that the lifetime is tied to the output of the function, not the input.

The error message indicates that a borrowed value is escaping the scope of a mutable reference, which violates Rust’s ownership and borrowing rules. You may see this error when working with closures, higher-order functions, or custom data structures that manage references across different lifetimes.

Fix E0384: Cannot Borrow as Mutable Because `self` is Also Borrowed as Immutable

Sun, 14 Jun 2026 19:56:04 +0800

1. Symptoms

When attempting to compile Rust code that returns a mutable reference to self from a method that takes an immutable &self parameter, the compiler emits error E0384.

Typical error messages you’ll encounter:

error[E0384]: cannot borrow `self` as mutable because it is also borrowed as immutable
  --> src/main.rs:10:9
   |
9  |     fn get_mut(&self) -> &mut Self {
   |                      ----- first immutable borrow occurs here
10 |         &mut *self
   |         ^^^^^^^^^ second borrow occurs here due to use of `self` in the return type
   |
   = note: this error occurs in the generation of the v-table for trait implementation
   = note: the old error code E0501 has been superseded
---

```text
error[E0384]: cannot borrow `self` as mutable because it is also borrowed as immutable
  --> src/lib.rs:15:13
   |
14 |     fn push(&mut self, elem: T) -> &mut T {
   |             --------- first borrow occurs due to use of `self` in the return type
15 |         let elem_ref = &mut self.data[self.len];
   |                        ^^^^^^^^^^^^^^^^^^^^^ second borrow occurs here

The error specifically states that you cannot borrow self as mutable because it is already borrowed as immutable. This is a fundamental violation of Rust’s borrowing rules, which enforce that you cannot have both an immutable and mutable reference to the same data at the same time.

Mutable-Reference on ErrorVault — Developer Error Code Dictionary

Fix E0713: Borrowed data escapes beyond mutable reference

1. Symptoms

Fix E0384: Cannot Borrow as Mutable Because `self` is Also Borrowed as Immutable

1. Symptoms