.NET 10 Preview 1 includes the following C# features & enhancements:
nameofin unbound generics- Implicit span conversions
fieldbacked properties- Modifiers on simple lambda parameters
- Experimental feature - String literals in data section
C# 14 updates:
- What's new in C# 14 documentation
- Breaking changes in C# 14
Field-backed properties provide a smoother path from auto-implemented properties to writing your own get and set accessors. You can access the compiler-generated backing field using the field contextual keyword in a get or set accessor. You can learn more about this feature in the article on the new field keyword.
The argument to a nameof expression can be an unbound generic type, like List<>. The result of the expression is "List". Previously, you'd need to supply a type argument for each type parameter. You can learn more in our docs on the nameof expression.
C# 14 introduces first-class support for Span<T> and ReadOnlySpan<T> in the language. Span<T> and ReadOnlySpan<T> are used in many key ways in C# and the runtime. This support involves new implicit conversions allowing more natural programming with these types.
You can learn more in the article on built-in types in the C# guide.
You can add parameter modifiers, such as ref, in, or out to lambda expressions without specifying the type of the parameters. This makes it easier for you to use these modifiers. You can learn more in the article on lambda expressions in the C# language reference.
This opt-in experimental feature allows changing how string literals in C# programs are emitted into PE files. By turning on the feature flag, string literals (where possible) are emitted as UTF-8 data into a different section of the PE file without a data limit. The emit format is similar to explicit UTF-8 string literals.
You can learn more by reading the feature documentation.