Mastering Implicit Span Conversions in C# 14 — Performance with Safety

Mastering Implicit Span Conversions in C# 14 — Performance with Safety C# 14 introduces first-class support for Span and ReadOnlySpan — powerful stack-allocated types for safe, high-performance memory access. One of the most important improvements is implicit span conversions, which enable smoother and safer manipulation of contiguous data structures like arrays, strings, and buffers. In this post, you'll learn: What Span and ReadOnlySpan are What implicit conversions C# 14 introduces Why they matter for performance and safety Real-world examples Best practices for using spans like a pro What Are Span and ReadOnlySpan? Span is a ref struct that provides a safe and efficient view over contiguous memory (like arrays, stackalloc blocks, or slices of buffers). ReadOnlySpan is its immutable counterpart. They are stack-only, avoiding heap allocations, and safe by design (no pointer arithmetic, bounds-checked). Span buffer = stackalloc byte[256]; buffer[0] = 42; Implicit Span Conversions in C# 14 C# 14 enhances span support with new implicit conversions, making Span and ReadOnlySpan easier to work with. Examples of implicit conversions: T[] → Span T[] → ReadOnlySpan Span → ReadOnlySpan

May 7, 2025 - 00:43

Mastering Implicit Span Conversions in C# 14 — Performance with Safety

C# 14 introduces first-class support for Span and ReadOnlySpan — powerful stack-allocated types for safe, high-performance memory access. One of the most important improvements is implicit span conversions, which enable smoother and safer manipulation of contiguous data structures like arrays, strings, and buffers.

In this post, you'll learn:

What Span and ReadOnlySpan are
What implicit conversions C# 14 introduces
Why they matter for performance and safety
Real-world examples
Best practices for using spans like a pro

What Are `Span` and `ReadOnlySpan`?

Span is a ref struct that provides a safe and efficient view over contiguous memory (like arrays, stackalloc blocks, or slices of buffers). ReadOnlySpan is its immutable counterpart.

They are stack-only, avoiding heap allocations, and safe by design (no pointer arithmetic, bounds-checked).

Span<byte> buffer = stackalloc byte[256];
buffer[0] = 42;

Implicit Span Conversions in C# 14

C# 14 enhances span support with new implicit conversions, making Span and ReadOnlySpan easier to work with.

Examples of implicit conversions:

T[] → Span
T[] → ReadOnlySpan
Span → ReadOnlySpan