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Tag: breaking-changes

2 posts

2026-09-17 mstest testing csharp

MSTest 4.4.1 Fixes the CS0121 Ambiguous Assert Calls That 4.4.0 Broke Below C# 14

MSTest 4.4.0 added Span<T> and ReadOnlySpan<T> overloads to Assert.Contains and Assert.DoesNotContain, which made ordinary array and string assertions fail with CS0121 on net8.0, net9.0, or any project below C# 14. MSTest 4.4.1, published on 2026-09-16, adds exact array overloads and constrained forwarders. Two explicit-generic call shapes still fail.

2026-05-19 csharp-14 csharp dotnet-10

Fix: C# 14 overload resolution breaking change with Span and ReadOnlySpan

After upgrading to C# 14 / .NET 10, calls like array.Contains, x.Reverse(), and MemoryMarshal.Cast suddenly bind to different overloads or stop compiling. Here is what changed and how to pin the old behaviour where it matters.