Const-Evaluation on ErrorVault — Developer Error Code Dictionary

Fix E0757: Invalid Reference to Generic Function Requiring Caller-Provided Type Parameters

Mon, 10 Aug 2026 19:56:04 +0800

Fix E0757: Invalid Reference to Generic Function Requiring Caller-Provided Type Parameters

Rust’s compiler employs a sophisticated type system that performs extensive validation during compilation. One of the more nuanced error codes you may encounter during development is E0757, which signals an invalid reference to a function that requires type parameters to be supplied by the caller. This error typically surfaces when the compiler cannot determine or infer the necessary generic parameters at the point where the function is referenced, leaving the function call in an ambiguous state.

Fix E0014: Conflicting Types in Const Context

Fri, 07 Aug 2026 03:08:04 +0800

Fix E0014: Conflicting Types in Const Context

Rust error E0014 is a compile-time error that indicates the compiler has detected a fundamental type conflict that prevents static evaluation of a constant. This error manifests during the const evaluation phase of compilation, where the compiler attempts to verify that all constant expressions can be resolved at compile time. The issue arises when the type of the value being assigned does not match the explicitly declared type annotation, or when the compiler cannot unify the types involved in a constant expression.

Fix E0669: Non-const function call in const context

Sun, 02 Aug 2026 12:44:04 +0800

1. Symptoms

When you encounter error E0669, the Rust compiler produces output similar to the following:

error[E0669]: calls in constants are limited to inherent functions, structs, variants, and trait methods
  --> src/main.rs:6:5
   |
6  |     do_something();
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The error message indicates that the function call cannot be evaluated at compile time because the called function lacks the const qualifier. The compiler explicitly states that constant evaluation contexts are restricted to inherent functions, struct constructors, enum variant constructors, and trait methods that have been marked as const.

Fix E0594: Attempted to Set a Constant with a Non-Constant Value

Fri, 10 Jul 2026 00:44:04 +0800

1. Symptoms

The Rust compiler produces error E0594 when a program attempts to assign a value to a constant that cannot be evaluated at compile time. The compiler emits a clear diagnostic message that identifies the offending assignment and explains the fundamental restriction.

Shell output from cargo build:

error[E0594]: cannot assign to an immutable constant
  --> src/main.rs:6:5
   |
6  |     X = 5;
   |     ^ cannot assign to an immutable constant

error: aborting due to 1 previous error

When the constant in question is initialized with a non-constant expression, the error message provides additional context about the nature of the expression that prevents compile-time evaluation:

Fix E0080: Evaluation of Constant Value Failed

Wed, 10 Jun 2026 00:44:04 +0800

1. Symptoms

The Rust compiler produces error E0080 when it encounters a constant expression that cannot be evaluated at compile time. This error manifests in several distinct ways that you should recognize.

Primary Error Message:

error[E0080]: evaluation of constant value failed –> src/main.rs:X:Y | X | const VALUE: Type = expression; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempt to compute value that was never initialized


**Common Variants:**

error[E0080]: evaluation of constant value failed –> src/main.rs:X:Y | X | const VALUE: u32 = 10 / 0; | ^ attempt to divide by zero