Compiles.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using Xunit;

namespace DllImportGenerator.UnitTests
{
    public class Compiles
    {
        public static IEnumerable<object[]> CodeSnippetsToCompile()
        {
            yield return new[] { CodeSnippets.TrivialClassDeclarations };
            yield return new[] { CodeSnippets.TrivialStructDeclarations };
            yield return new[] { CodeSnippets.MultipleAttributes };
            yield return new[] { CodeSnippets.NestedNamespace };
            yield return new[] { CodeSnippets.NestedTypes };
            yield return new[] { CodeSnippets.UnsafeContext };
            yield return new[] { CodeSnippets.UserDefinedEntryPoint };
            yield return new[] { CodeSnippets.AllGeneratedDllImportNamedArguments };
            yield return new[] { CodeSnippets.DefaultParameters };
            yield return new[] { CodeSnippets.UseCSharpFeaturesForConstants };

            // Parameter / return types
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<byte>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<sbyte>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<short>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<ushort>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<uint>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<long>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<ulong>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<float>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<double>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<bool>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<IntPtr>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<UIntPtr>() };

            // Arrays
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<byte>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<sbyte>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<short>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<ushort>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<uint>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<long>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<ulong>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<float>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<double>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<bool>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<IntPtr>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParametersAndModifiers<UIntPtr>() };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<byte>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<sbyte>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<short>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<ushort>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<int>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<uint>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<long>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<ulong>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<IntPtr>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<UIntPtr>(isByRef: false) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<byte>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<sbyte>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<short>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<ushort>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<int>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<uint>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<long>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<ulong>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<IntPtr>(isByRef: true) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithSizeParam<UIntPtr>(isByRef: true) };

            // CharSet
            yield return new[] { CodeSnippets.BasicParametersAndModifiersWithCharSet<char>(CharSet.Unicode) };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersWithCharSet<string>(CharSet.Unicode) };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersWithCharSet<string>(CharSet.Ansi) };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersWithCharSet<string>(CharSet.Auto) };

            // MarshalAs
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<bool>(UnmanagedType.Bool) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<bool>(UnmanagedType.VariantBool) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<bool>(UnmanagedType.I1) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<char>(UnmanagedType.I2) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<char>(UnmanagedType.U2) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<IntPtr>(UnmanagedType.SysInt) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<UIntPtr>(UnmanagedType.SysUInt) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<string>(UnmanagedType.LPWStr) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<string>(UnmanagedType.LPTStr) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<string>(UnmanagedType.LPUTF8Str) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiers<string>(UnmanagedType.LPStr) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithNestedMarshalInfo<string>(UnmanagedType.LPWStr) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithNestedMarshalInfo<string>(UnmanagedType.LPUTF8Str) };
            yield return new[] { CodeSnippets.MarshalAsArrayParameterWithNestedMarshalInfo<string>(UnmanagedType.LPStr) };

            // [In, Out] attributes
            // By value non-blittable array
            yield return new[] { CodeSnippets.ByValueParameterWithModifier<bool[]>("Out") };
            yield return new[] { CodeSnippets.ByValueParameterWithModifier<bool[]>("In, Out") };

            // Enums
            yield return new[] { CodeSnippets.EnumParameters };

            // Pointers
            yield return new[] { CodeSnippets.PointerParameters<byte>() };
            yield return new[] { CodeSnippets.PointerParameters<sbyte>() };
            yield return new[] { CodeSnippets.PointerParameters<short>() };
            yield return new[] { CodeSnippets.PointerParameters<ushort>() };
            yield return new[] { CodeSnippets.PointerParameters<int>() };
            yield return new[] { CodeSnippets.PointerParameters<uint>() };
            yield return new[] { CodeSnippets.PointerParameters<long>() };
            yield return new[] { CodeSnippets.PointerParameters<ulong>() };
            yield return new[] { CodeSnippets.PointerParameters<float>() };
            yield return new[] { CodeSnippets.PointerParameters<double>() };
            yield return new[] { CodeSnippets.PointerParameters<bool>() };
            yield return new[] { CodeSnippets.PointerParameters<IntPtr>() };
            yield return new[] { CodeSnippets.PointerParameters<UIntPtr>() };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersUnsafe("void*") };

            // Delegates
            yield return new[] { CodeSnippets.DelegateParametersAndModifiers };
            yield return new[] { CodeSnippets.DelegateMarshalAsParametersAndModifiers };

            // Function pointers
            yield return new[] { CodeSnippets.BasicParametersAndModifiersUnsafe("delegate* <void>") };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersUnsafe("delegate* unmanaged<void>") };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersUnsafe("delegate* unmanaged<int, int>") };
            yield return new[] { CodeSnippets.BasicParametersAndModifiersUnsafe("delegate* unmanaged[Stdcall]<int, int>") };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiersUnsafe("delegate* <int>", UnmanagedType.FunctionPtr) };
            yield return new[] { CodeSnippets.MarshalAsParametersAndModifiersUnsafe("delegate* unmanaged<int>", UnmanagedType.FunctionPtr) };

            // Structs
            yield return new[] { CodeSnippets.BlittableStructParametersAndModifiers };

            // SafeHandle
            yield return new[] { CodeSnippets.BasicParametersAndModifiers("Microsoft.Win32.SafeHandles.SafeFileHandle") };
            yield return new[] { CodeSnippets.BasicParameterByValue("System.Runtime.InteropServices.SafeHandle") };
            yield return new[] { CodeSnippets.SafeHandleWithCustomDefaultConstructorAccessibility(privateCtor: false) };
            yield return new[] { CodeSnippets.SafeHandleWithCustomDefaultConstructorAccessibility(privateCtor: true) };

            // PreserveSig
            yield return new[] { CodeSnippets.PreserveSigFalseVoidReturn };
            yield return new[] { CodeSnippets.PreserveSigFalse<byte>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<sbyte>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<short>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<ushort>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<int>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<uint>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<long>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<ulong>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<float>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<double>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<bool>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<IntPtr>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<UIntPtr>() };
            yield return new[] { CodeSnippets.PreserveSigFalse("Microsoft.Win32.SafeHandles.SafeFileHandle") };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<byte>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<sbyte>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<short>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<ushort>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<int>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<uint>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<long>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<ulong>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<float>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<double>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<bool>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<IntPtr>() };
            yield return new[] { CodeSnippets.ArrayPreserveSigFalse<UIntPtr>() };

            // Custom type marshalling
            yield return new[] { CodeSnippets.CustomStructMarshallingParametersAndModifiers };
            yield return new[] { CodeSnippets.CustomStructMarshallingStackallocParametersAndModifiersNoRef };
            yield return new[] { CodeSnippets.CustomStructMarshallingStackallocValuePropertyParametersAndModifiersNoRef };
            yield return new[] { CodeSnippets.CustomStructMarshallingOptionalStackallocParametersAndModifiers };
            yield return new[] { CodeSnippets.CustomStructMarshallingValuePropertyParametersAndModifiers };
            yield return new[] { CodeSnippets.CustomStructMarshallingPinnableParametersAndModifiers };
            yield return new[] { CodeSnippets.CustomStructMarshallingNativeTypePinnable };
            yield return new[] { CodeSnippets.CustomStructMarshallingMarshalUsingParametersAndModifiers };
            yield return new[] { CodeSnippets.ArrayMarshallingWithCustomStructElement };
            yield return new[] { CodeSnippets.ArrayMarshallingWithCustomStructElementWithValueProperty };

            // Escaped C# keyword identifiers
            yield return new[] { CodeSnippets.ByValueParameterWithName("Method", "@event") };
            yield return new[] { CodeSnippets.ByValueParameterWithName("Method", "@var") };
            yield return new[] { CodeSnippets.ByValueParameterWithName("@params", "i") };

            // Generics
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<byte>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<sbyte>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<short>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<ushort>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<uint>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<long>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<ulong>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<float>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<double>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<IntPtr>() };
            yield return new[] { CodeSnippets.MaybeBlittableGenericTypeParametersAndModifiers<UIntPtr>() };

            // Implicit blittable types
            yield return new[] { CodeSnippets.ImplicitlyBlittableStructParametersAndModifiers() };
            yield return new[] { CodeSnippets.ImplicitlyBlittableStructParametersAndModifiers("internal") };
            yield return new[] { CodeSnippets.ImplicitlyBlittableGenericTypeParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.ImplicitlyBlittableGenericTypeParametersAndModifiers<int>("internal") };

            // Custom collection marshalling
            yield return new[] { CodeSnippets.CollectionByValue<byte>() };
            yield return new[] { CodeSnippets.CollectionByValue<sbyte>() };
            yield return new[] { CodeSnippets.CollectionByValue<short>() };
            yield return new[] { CodeSnippets.CollectionByValue<ushort>() };
            yield return new[] { CodeSnippets.CollectionByValue<int>() };
            yield return new[] { CodeSnippets.CollectionByValue<uint>() };
            yield return new[] { CodeSnippets.CollectionByValue<long>() };
            yield return new[] { CodeSnippets.CollectionByValue<ulong>() };
            yield return new[] { CodeSnippets.CollectionByValue<float>() };
            yield return new[] { CodeSnippets.CollectionByValue<double>() };
            yield return new[] { CodeSnippets.CollectionByValue<bool>() };
            yield return new[] { CodeSnippets.CollectionByValue<IntPtr>() };
            yield return new[] { CodeSnippets.CollectionByValue<UIntPtr>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<byte[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<sbyte[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<short[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<ushort[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<int[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<uint[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<long[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<ulong[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<float[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<double[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<bool[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<IntPtr[]>() };
            yield return new[] { CodeSnippets.MarshalUsingCollectionCountInfoParametersAndModifiers<UIntPtr[]>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<byte>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<sbyte>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<short>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<ushort>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<uint>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<long>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<ulong>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<float>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<double>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<bool>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<IntPtr>() };
            yield return new[] { CodeSnippets.CustomCollectionDefaultMarshallerParametersAndModifiers<UIntPtr>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<byte>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<sbyte>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<short>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<ushort>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<uint>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<long>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<ulong>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<float>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<double>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<bool>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<IntPtr>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerParametersAndModifiers<UIntPtr>() };
            yield return new[] { CodeSnippets.CustomCollectionCustomMarshallerReturnValueLength<int>() };
            yield return new[] { CodeSnippets.GenericCollectionWithCustomElementMarshalling };
            yield return new[] { CodeSnippets.CollectionsOfCollectionsStress };
        }

        [ConditionalTheory]
        [MemberData(nameof(CodeSnippetsToCompile))]
        public async Task ValidateSnippets(string source)
        {
            Compilation comp = await TestUtils.CreateCompilation(source);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(comp, out var generatorDiags, new Microsoft.Interop.DllImportGenerator());
            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();
            Assert.Empty(newCompDiags);
        }

        public static IEnumerable<object[]> CodeSnippetsToCompileWithPreprocessorSymbols()
        {
            yield return new object[] { CodeSnippets.PreprocessorIfAroundFullFunctionDefinition("Foo"), new string[] { "Foo" } };
            yield return new object[] { CodeSnippets.PreprocessorIfAroundFullFunctionDefinition("Foo"), Array.Empty<string>() };
            yield return new object[] { CodeSnippets.PreprocessorIfAroundFullFunctionDefinitionWithFollowingFunction("Foo"), new string[] { "Foo" } };
            yield return new object[] { CodeSnippets.PreprocessorIfAroundFullFunctionDefinitionWithFollowingFunction("Foo"), Array.Empty<string>() };
            yield return new object[] { CodeSnippets.PreprocessorIfAfterAttributeAroundFunction("Foo"), new string[] { "Foo" } };
            yield return new object[] { CodeSnippets.PreprocessorIfAfterAttributeAroundFunction("Foo"), Array.Empty<string>() };
            yield return new object[] { CodeSnippets.PreprocessorIfAfterAttributeAroundFunctionAdditionalFunctionAfter("Foo"), new string[] { "Foo" } };
            yield return new object[] { CodeSnippets.PreprocessorIfAfterAttributeAroundFunctionAdditionalFunctionAfter("Foo"), Array.Empty<string>() };
        }

        [ConditionalTheory]
        [MemberData(nameof(CodeSnippetsToCompileWithPreprocessorSymbols))]
        public async Task ValidateSnippetsWithPreprocessorDefintions(string source, IEnumerable<string> preprocessorSymbols)
        {
            Compilation comp = await TestUtils.CreateCompilation(source, preprocessorSymbols: preprocessorSymbols);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(comp, out var generatorDiags, new Microsoft.Interop.DllImportGenerator());
            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();
            Assert.Empty(newCompDiags);
        }

        public static IEnumerable<object[]> CodeSnippetsToValidateFallbackForwarder()
        {
            yield return new object[] { CodeSnippets.UserDefinedEntryPoint, TestTargetFramework.Net, true };

            // Confirm that all unsupported target frameworks can be generated.
            {
                string code = CodeSnippets.BasicParametersAndModifiers<byte>(CodeSnippets.GeneratedDllImportAttributeDeclaration);
                yield return new object[] { code, TestTargetFramework.Net5, false };
                yield return new object[] { code, TestTargetFramework.Core, false };
                yield return new object[] { code, TestTargetFramework.Standard, false };
                yield return new object[] { code, TestTargetFramework.Framework, false };
            }

            // Confirm that all unsupported target frameworks fallback to a forwarder.
            {
                string code = CodeSnippets.BasicParametersAndModifiers<byte[]>(CodeSnippets.GeneratedDllImportAttributeDeclaration);
                yield return new object[] { code, TestTargetFramework.Net5, true };
                yield return new object[] { code, TestTargetFramework.Core, true };
                yield return new object[] { code, TestTargetFramework.Standard, true };
                yield return new object[] { code, TestTargetFramework.Framework, true };
            }

            // Confirm that all unsupported target frameworks fallback to a forwarder.
            {
                string code = CodeSnippets.BasicParametersAndModifiersWithCharSet<string>(CharSet.Unicode, CodeSnippets.GeneratedDllImportAttributeDeclaration);
                yield return new object[] { code, TestTargetFramework.Net5, true };
                yield return new object[] { code, TestTargetFramework.Core, true };
                yield return new object[] { code, TestTargetFramework.Standard, true };
                yield return new object[] { code, TestTargetFramework.Framework, true };
            }
        }

        [ConditionalTheory]
        [ActiveIssue("https://github.com/dotnet/runtime/issues/63635", TestPlatforms.OSX)]
        [MemberData(nameof(CodeSnippetsToValidateFallbackForwarder))]
        public async Task ValidateSnippetsFallbackForwarder(string source, TestTargetFramework targetFramework, bool expectFallbackForwarder)
        {
            Compilation comp = await TestUtils.CreateCompilation(source, targetFramework);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(
                comp,
                out var generatorDiags,
                new Microsoft.Interop.DllImportGenerator());

            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();
            Assert.Empty(newCompDiags);

            // Verify that the forwarder generates the method as a DllImport.
            SyntaxTree generatedCode = newComp.SyntaxTrees.Last();
            SemanticModel model = newComp.GetSemanticModel(generatedCode);
            var methods = generatedCode.GetRoot()
                .DescendantNodes().OfType<MethodDeclarationSyntax>()
                .ToList();
            MethodDeclarationSyntax generatedMethod = Assert.Single(methods);

            IMethodSymbol method = model.GetDeclaredSymbol(generatedMethod)!;

            // If we expect fallback forwarder, then the DllImportData will not be null.
            Assert.Equal(expectFallbackForwarder, method.GetDllImportData() is not null);
        }

        public static IEnumerable<object[]> FullyBlittableSnippetsToCompile()
        {
            yield return new[] { CodeSnippets.UserDefinedEntryPoint };
            yield return new[] { CodeSnippets.BasicParameterByValue("int") };
        }

        [ConditionalTheory]
        [MemberData(nameof(FullyBlittableSnippetsToCompile))]
        public async Task ValidateSnippetsWithBlittableAutoForwarding(string source)
        {
            Compilation comp = await TestUtils.CreateCompilation(source);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(
                comp,
                out var generatorDiags,
                new Microsoft.Interop.DllImportGenerator());

            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();
            Assert.Empty(newCompDiags);

            // Verify that the forwarder generates the method as a DllImport.
            SyntaxTree generatedCode = newComp.SyntaxTrees.Last();
            SemanticModel model = newComp.GetSemanticModel(generatedCode);
            var methods = generatedCode.GetRoot()
                .DescendantNodes().OfType<MethodDeclarationSyntax>()
                .ToList();

            Assert.All(methods, method => Assert.NotNull(model.GetDeclaredSymbol(method)!.GetDllImportData()));
        }

        public static IEnumerable<object[]> SnippetsWithBlittableTypesButNonBlittableDataToCompile()
        {
            yield return new[] { CodeSnippets.AllGeneratedDllImportNamedArguments };
            yield return new[] { CodeSnippets.BasicParametersAndModifiers<int>() };
            yield return new[] { CodeSnippets.PreserveSigFalse<int>() };
        }

        [ConditionalTheory]
        [MemberData(nameof(SnippetsWithBlittableTypesButNonBlittableDataToCompile))]
        public async Task ValidateSnippetsWithBlittableTypesButNonBlittableMetadataDoNotAutoForward(string source)
        {
            Compilation comp = await TestUtils.CreateCompilation(source);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(
                comp,
                out var generatorDiags,
                new Microsoft.Interop.DllImportGenerator());

            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();
            Assert.Empty(newCompDiags);

            // Verify that the generator generates stubs with inner DllImports for all methods.
            SyntaxTree generatedCode = newComp.SyntaxTrees.Last();
            SemanticModel model = newComp.GetSemanticModel(generatedCode);
            int numStubMethods = generatedCode.GetRoot()
                .DescendantNodes().OfType<MethodDeclarationSyntax>()
                .Count();
            int numInnerDllImports = generatedCode.GetRoot()
                .DescendantNodes().OfType<LocalFunctionStatementSyntax>()
                .Count();

            Assert.Equal(numStubMethods, numInnerDllImports);
        }

        public static IEnumerable<object[]> CodeSnippetsToCompileWithMarshalType()
        {
            yield break;
        }

#pragma warning disable xUnit1004 // Test methods should not be skipped.
                                  // If we have any new experimental APIs that we are implementing that have not been approved,
                                  // we will add new scenarios for this test.
        [ConditionalTheory(Skip = "No current scenarios to test.")]
#pragma warning restore
        [MemberData(nameof(CodeSnippetsToCompileWithMarshalType))]
        public async Task ValidateSnippetsWithMarshalType(string source)
        {
            Compilation comp = await TestUtils.CreateCompilation(source);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(
                comp,
                new DllImportGeneratorOptionsProvider(useMarshalType: true, generateForwarders: false),
                out var generatorDiags,
                new Microsoft.Interop.DllImportGenerator());

            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();

            Assert.All(newCompDiags, diag =>
            {
                Assert.Equal("CS0117", diag.Id);
                Assert.StartsWith("'Marshal' does not contain a definition for ", diag.GetMessage());
            });
        }

        public static IEnumerable<object[]> CodeSnippetsToCompileMultipleSources()
        {
            yield return new object[] { new[] { CodeSnippets.BasicParametersAndModifiers<int>(), CodeSnippets.MarshalAsParametersAndModifiers<bool>(UnmanagedType.Bool) } };
            yield return new object[] { new[] { CodeSnippets.BasicParametersAndModifiersWithCharSet<int>(CharSet.Unicode), CodeSnippets.MarshalAsParametersAndModifiers<bool>(UnmanagedType.Bool) } };
            yield return new object[] { new[] { CodeSnippets.BasicParameterByValue("int[]"), CodeSnippets.BasicParameterWithByRefModifier("ref", "int") } };
        }

        [ConditionalTheory]
        [MemberData(nameof(CodeSnippetsToCompileMultipleSources))]
        public async Task ValidateSnippetsWithMultipleSources(string[] sources)
        {
            Compilation comp = await TestUtils.CreateCompilation(sources);
            TestUtils.AssertPreSourceGeneratorCompilation(comp);

            var newComp = TestUtils.RunGenerators(comp, out var generatorDiags, new Microsoft.Interop.DllImportGenerator());
            Assert.Empty(generatorDiags);

            var newCompDiags = newComp.GetDiagnostics();
            Assert.Empty(newCompDiags);
        }
    }
}