Nullable Reference Types are a feature in C# that helps developers avoid null reference exceptions by providing compile-time checks for nullability. This feature was introduced in C# 8.0 and is designed to improve code quality and reduce runtime errors.
When the compiler cannot handle all cases, so developers may need to use the null-forgiving operator ! to suppress warnings. This operator tells the compiler that the developer is confident that a value will not be null, even if the compiler cannot guarantee it. However, using this operator should be done with caution, as it can lead to runtime exceptions if the value is actually null.
Over time, the compiler or the libraries may improve, and the need for the null-forgiving operator may decrease. Here's an example of useless null-forgiving operator:
C#
if (!string.IsNullOrEmpty(someString))
{
_ = someString!.Length; // null-forgiving operator is useless here
}
It's not feasable to navigate across all code and remove the operator. Instead, you can automate the process of removing the null-forgiving operator using Roslyn and the MSBuildWorkspace (see this blog post for more details).
You can use the project https://github.com/jnm2/SuppressionCleanupTool from Joseph Musser to check for all null-forgiving operators in a solution and remove them if they are not needed. The idea of the tool is to remove the null-forgiving operator one by one from the code and check if the compiler reports a new warning. If it does, the operator is kept. If not, the operator is removed. Simple and effective.
Shell
git clone https://github.com/jnm2/SuppressionCleanupTool.git
cd SuppressionCleanupTool
dotnet run --project src/SuppressionCleanupTool.csproj -- mysolution.sln
It can take a while to run depending on the size of the solution, so be patient.
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