What causes "Indices for UInt4 run from 0 to 3, inclusive." in stride3d/stride?

Clamp or validate the index to 0..3 before indexing.

stride3d/stride · error · ArgumentOutOfRangeException

Indices for UInt4 run from 0 to 3, inclusive.

Error message

Indices for UInt4 run from 0 to 3, inclusive.

What it means

Indexer bounds guard on UInt4 this[index]: the requested component index is outside [0,3]; none of the switch cases matched, so there is no X/Y/Z/W component to return. The faulting input is the index argument to the indexer.

Solutions

Clamp or validate the index to 0..3 before indexing.
Fix loop bounds to i < 4 when iterating UInt4 components.
Use component properties (X, Y, Z, W) directly when the index is known statically.

Example fix

// before
for (int i = 0; i < 5; i++) sum += v[i];
// after
for (int i = 0; i < 4; i++) sum += v[i];

Defensive patterns

Strategy: validation

Validate before calling

if (index < 0 || index > 3)
    throw new ArgumentOutOfRangeException(nameof(index), "UInt4 index must be 0..3.");
var component = v[index];

Type guard

bool IsValidUInt4Index(int i) => i >= 0 && i <= 3;

Try / catch

try
{
    component = v[index];
}
catch (ArgumentOutOfRangeException)
{
    component = 0; // or rethrow with context about the bad index
}

Prevention

Use compile-time constants or named properties (X/Y/Z/W) instead of runtime indices.
Bound component loops with the vector's component count (4 for UInt4).
Never reuse loop bounds from other vector types when indexing.

When it happens

Trigger: Reading v[i] on a UInt4 with i outside 0..3, e.g. looping to i < 5 for a 4-component type, or using a negative index computed from an off-by-one expression.

Common situations: Generic component-copy loops sized from a different vector type; iterating both a Vector4-sized buffer and UInt4 values with a shared loop bound; computed index from bad data.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/0613eb133c661701. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Mathematics/UInt4.cs:161

    /// <returns>The value of the component at the specified index.</returns>
    /// <exception cref = "System.ArgumentOutOfRangeException">Thrown when the <paramref name = "index" /> is out of the range [0, 3].</exception>
    public uint this[uint index]
    {
        get
        {
            switch (index)
            {
                case 0:
                    return X;
                case 1:
                    return Y;
                case 2:
                    return Z;
                case 3:
                    return W;
            }

            throw new ArgumentOutOfRangeException(nameof(index), "Indices for UInt4 run from 0 to 3, inclusive.");
        }

        set
        {
            switch (index)
            {
                case 0:
                    X = value;
                    break;
                case 1:
                    Y = value;
                    break;
                case 2:
                    Z = value;
                    break;
                case 3:
                    W = value;
                    break;

View on GitHub (pinned to 96fad776d2)