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Tag: csharp-14

27 posts · Page 1 of 3

2026-10-28 errors csharp csharp-14

Fix: [MemberNotNull] has no effect on a static factory method and CS8618 still fires

CS8618 is checked when the constructor exits, and [MemberNotNull] on a static method is silently ignored for instance members. Pass the values into a private constructor instead.

2026-10-16 csharp csharp-14 records

What Does a C# `with` Expression Actually Copy, and Why Don't Computed Record Properties Recalculate?

A with expression calls the record's compiler-generated <Clone>$ method, which runs a copy constructor that copies every instance field and skips all initializers. That is why properties initialized from other properties, cached values, and Guid IDs come out stale. Measured on .NET 10 with C# 14, with the fixes that actually work.

2026-10-15 csharp csharp-14 dotnet-11

What Is ref-safe-context in C#, and How Does the Compiler Decide It for ref Locals?

ref-safe-context is the scope in which a reference to a variable stays valid. Here are the four contexts, the rule that fixes a ref local's context at its initializer, why ref reassignment can never widen or narrow it, and the CS8157, CS8168, CS8374 and CS9079 errors that fall out of it, with compiler output from C# 14 on .NET 10 and .NET 11 RC1.

2026-09-01 comparison csharp csharp-14

Returning a Task directly vs async/await passthrough in a C# repository method: which should you use?

Eliding async/await in a repository passthrough saves about 6 ns and 72 bytes, and costs you a stack frame, try/catch semantics, and safe disposal. Keep return await unless the method is a pure passthrough on a measured hot path.

2026-08-23 how-to csharp csharp-14

How to write a static extension member that applies to every enum type in C# 14

Declare a generic extension block with a struct, Enum constraint and you get Status.Values, Status.Count, and Status.Parse on every enum in your solution. The receiver shape, the CS0704 and CS0428 traps, and why you must cache Enum.GetValues.

2026-08-18 errors csharp csharp-14

Fix: The call is ambiguous between the following methods or properties after moving to C# 14 extension members

CS0121 after moving an extension method into a C# 14 extension block: the compiler still emits the old static form. Delete the duplicate or qualify the call.

2026-08-16 system-text-json csharp csharp-14

How to make System.Text.Json ignore a property that has the required modifier

[JsonIgnore] on a required member throws InvalidOperationException: marked required but does not specify a setter. Here is why the two features collide and the four ways to ignore the property anyway, measured on .NET 10.

2026-08-05 errors csharp csharp-14

Fix: CS1998 "This async method lacks 'await' operators and will run synchronously" in C#

CS1998 means an async method has no await, so it runs synchronously. Drop the async modifier and return Task.FromResult, or add the await you forgot.

2026-07-21 errors csharp csharp-14

Fix: CS4014 "Because this call is not awaited, execution of the current method continues" in C#

CS4014 means you called a Task-returning method without awaiting it. Add await, or discard with _ = if fire-and-forget is truly intended, and handle exceptions.

2026-07-20 errors csharp csharp-14

Fix: CS8618 "Non-nullable property must contain a non-null value when exiting constructor" in C#

CS8618 means a non-nullable field or property was not initialized by the time the constructor finished. Set it in the constructor, give it a default, mark it required, or make it nullable.