Destructor on ErrorVault — Developer Error Code Dictionary

Fix E0493: Destructor Cannot Be Called in Constant Function

Sat, 08 Aug 2026 22:20:04 +0800

1. Symptoms

When the Rust compiler encounters E0493, it produces an error message indicating that a destructor cannot be invoked during constant evaluation. The compiler provides context about which type’s destructor is problematic and where the invalid call occurs.

Typical compiler output looks like this:

error[E0493]: destructor of `MyStruct` cannot be called in constant function
  --> src/main.rs:10:5
   |
10 |     drop(value);
   |     ^^^^^^^^^^^ calling the destructor of `MyStruct` in constant function

The error manifests in several common scenarios. When using the drop function on a type that implements Drop inside a const fn, the compiler rejects the code. Similarly, when a constant initialization implicitly requires destructor execution, such as when a const value goes out of scope during const evaluation, the same error appears. Explicit calls to std::mem::drop within constant contexts also trigger this error when the dropped type has a custom destructor.

Fix E0714: Destructors Cannot Be Evaluated at Constant Expression Compilation

Fri, 07 Aug 2026 15:08:04 +0800

1. Symptoms

The Rust compiler emits error E0714 when you attempt to use a pattern involving types with destructors in a const or static item context where the destructor cannot be evaluated at compile time. The error manifests with a clear diagnostic message indicating that destructors are forbidden during constant evaluation.

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

error[E0714]: destructors cannot be evaluated at constant expression compilation
  --> src/main.rs:6:13
   |
6  | const VALUE: Option<Box<i32>> = Some(Box::new(42));
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error occurs in the expansion of static item initialization

The error points to the exact line where the problematic pattern appears, and the note clarifies that the issue occurs during static item initialization. In more complex scenarios involving tuple destructuring, you might see additional context about which part of the pattern triggered the evaluation:

Fix E0796: Destructor Names Must Not Be Used Outside of Their Trait

Tue, 28 Jul 2026 00:44:04 +0800

1. Symptoms

When the Rust compiler encounters error E0796, you will see a message similar to the following in your build output:

error[E0796]: destructor names must not be used outside of their trait
  --> src/main.rs:10:5
   |
10 |     SomeType::drop(some_instance);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot call a destructor by name
   |
   = note: this error occurs if you try to call a destructor directly.
     Use the `std::mem::drop` function or implement the `Drop` trait instead.

The compiler will reject the code and halt compilation at the point where you attempted to invoke the destructor. Common patterns that trigger this error include explicit calls to TypeName::drop(), attempting to manually run cleanup code through the destructor mechanism, or trying to access drop-related internals directly from user code. The error message explicitly guides developers toward the std::mem::drop function as the idiomatic alternative for explicitly dropping values.