// begin creating the source we'll inject into the users compilation
var sourceBuilder = new StringBuilder(@"
using System;
namespace HelloWorldGenerated
{
    public static class HelloWorld
    {
        public static void SayHello()
        {
            Console.WriteLine(""Hello from generated code!"");
            Console.WriteLine(""The following syntax trees existed in the compilation that created this program:"");
");

// using the context, get a list of syntax trees in the users compilation
var syntaxTrees = context.Compilation.SyntaxTrees;

// add the filepath of each tree to the class we're building
foreach (SyntaxTree tree in syntaxTrees)
{
    sourceBuilder.AppendLine([email protected]"Console.WriteLine(@"" - {tree.FilePath}"");");
}

// finish creating the source to inject
sourceBuilder.Append(@"
        }
    }
}");