DioxusLabs/dioxus · error

const vec capacity exceeded

Error message

const vec capacity exceeded

What it means

ConstVec is backed by a fixed MAX_SIZE array. Pushing more elements than that capacity (commonly via extend in const contexts) exceeds the backing storage and triggers this panic, since const code cannot grow an allocation.

Source

Thrown at packages/dioxus-const-vec/src/lib.rs:152

        }
    }

    /// Push a value onto the end of the [`ConstVec`].
    ///
    /// # Example
    ///
    /// ```rust
    /// # use dioxus_const_vec::ConstVec;
    /// const ONE: ConstVec<u8> = {
    ///     let mut vec = ConstVec::new();
    ///     vec.push(1);
    ///     vec
    /// };
    /// assert_eq!(ONE.as_ref(), &[1]);
    /// ```
    pub const fn push(&mut self, value: T) {
        if self.len as usize >= MAX_SIZE {
            panic!("const vec capacity exceeded");
        }
        self.memory[self.len as usize] = MaybeUninit::new(value);
        self.len += 1;
    }

    /// Extend the [`ConstVec`] with the contents of a slice.
    ///
    /// # Example
    ///
    /// ```rust
    /// # use dioxus_const_vec::ConstVec;
    /// const ONE: ConstVec<u8> = {
    ///     let mut vec = ConstVec::new();
    ///     vec.extend(&[1, 2, 3]);
    ///     vec
    /// };
    /// assert_eq!(ONE.as_ref(), &[1, 2, 3]);
    /// ```

View on GitHub (pinned to 24f6a829df)

Solutions

1. The const vec is at its fixed capacity. Increase the capacity parameter or push fewer elements.

When it happens

Trigger: Thrown at packages/dioxus-const-vec/src/lib.rs:152 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of DioxusLabs/dioxus@24f6a829df (2026-08-23). Data as JSON: /api/errors/31409f8afcf340f5. Report an issue: GitHub.