Code inspection: Burst: String.Format(format, ...) invalid argument type

This inspection reports unsupported argument types passed to string.Format() in code compiled by the Burst compiler.

In Burst, string.Format only supports a limited set of arguments. If one of the format arguments is a managed type, or even a string, this inspection warns because Burst only supports value-type arguments in this context. Managed objects, such as CultureInfo, also trigger this warning.

Example

In this example, a string argument is passed to string.Format. This is not supported in Burst-compiled code.

                using Unity.Burst;
                using Unity.Jobs;

                [BurstCompile]
                public struct ExampleJob : IJob
                {
                    public void Execute()
                    {
                        // Reported: String arguments are not supported in string.Format within Burst
                        string.Format("Player: {0}", "Alice");
                    }
                }
            

                using Unity.Burst;
                using Unity.Jobs;

                [BurstCompile]
                public struct ExampleJob : IJob
                {
                    public int score;

                    public void Execute()
                    {
                        // Correct: Use Burst-compatible value types
                        string.Format("Score: {0}", score);
                    }
                }
            

Quick-fix

This inspection does not provide a dedicated quick-fix. Fix it manually by replacing unsupported format arguments with Burst-compatible value types, or by moving the formatting out of Burst-compiled code.

26 March 2026