[DllImportGenerator] Remove DLLIMPORTGENERATOR_ENABLED define (#63464)

6 files changed, 59 insertions, 304 deletions

diff --git a/eng/generators.targets b/eng/generators.targets
index 4c32554b5e2..843842937ef 100644
--- a/eng/generators.targets
+++ b/eng/generators.targets
@@ -84,10 +84,6 @@
         <DllImportGenerator_UseInternalUnsafeType>true</DllImportGenerator_UseInternalUnsafeType>
         <DefineConstants>$(DefineConstants);DLLIMPORTGENERATOR_INTERNALUNSAFE</DefineConstants>
     </PropertyGroup>
-
-    <PropertyGroup>
-      <DefineConstants>$(DefineConstants);DLLIMPORTGENERATOR_ENABLED</DefineConstants>
-    </PropertyGroup>
   </Target>
 
   <Import Project="$(LibrariesProjectRoot)System.Runtime.InteropServices/gen/DllImportGenerator/Microsoft.Interop.DllImportGenerator.props" />
diff --git a/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Analyzers/ConvertToGeneratedDllImportFixer.cs b/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Analyzers/ConvertToGeneratedDllImportFixer.cs
index c99f64fcc48..829d508a726 100644
--- a/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Analyzers/ConvertToGeneratedDllImportFixer.cs
+++ b/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Analyzers/ConvertToGeneratedDllImportFixer.cs
@@ -26,8 +26,7 @@ namespace Microsoft.Interop.Analyzers
 
         public override FixAllProvider GetFixAllProvider() => WellKnownFixAllProviders.BatchFixer;
 
-        public const string NoPreprocessorDefinesKey = "ConvertToGeneratedDllImport";
-        public const string WithPreprocessorDefinesKey = "ConvertToGeneratedDllImportPreprocessor";
+        private const string ConvertToGeneratedDllImportKey = "ConvertToGeneratedDllImport";
 
         private static readonly string[] s_preferredAttributeArgumentOrder =
             {
@@ -70,33 +69,18 @@ namespace Microsoft.Interop.Analyzers
             if (!TryGetAttribute(methodSymbol, dllImportAttrType, out AttributeData? dllImportAttr))
                 return;
 
-            // Register code fixes with two options for the fix - using preprocessor or not.
+            // Register code fix
             context.RegisterCodeFix(
                 CodeAction.Create(
-                    Resources.ConvertToGeneratedDllImportNoPreprocessor,
+                    Resources.ConvertToGeneratedDllImport,
                     cancelToken => ConvertToGeneratedDllImport(
                         context.Document,
                         methodSyntax,
                         methodSymbol,
                         dllImportAttr!,
                         generatedDllImportAttrType,
-                        usePreprocessorDefines: false,
                         cancelToken),
-                    equivalenceKey: NoPreprocessorDefinesKey),
-                context.Diagnostics);
-
-            context.RegisterCodeFix(
-                CodeAction.Create(
-                    Resources.ConvertToGeneratedDllImportWithPreprocessor,
-                    cancelToken => ConvertToGeneratedDllImport(
-                        context.Document,
-                        methodSyntax,
-                        methodSymbol,
-                        dllImportAttr!,
-                        generatedDllImportAttrType,
-                        usePreprocessorDefines: true,
-                        cancelToken),
-                    equivalenceKey: WithPreprocessorDefinesKey),
+                    equivalenceKey: ConvertToGeneratedDllImportKey),
                 context.Diagnostics);
         }
 
@@ -106,7 +90,6 @@ namespace Microsoft.Interop.Analyzers
             IMethodSymbol methodSymbol,
             AttributeData dllImportAttr,
             INamedTypeSymbol generatedDllImportAttrType,
-            bool usePreprocessorDefines,
             CancellationToken cancellationToken)
         {
             DocumentEditor editor = await DocumentEditor.CreateAsync(doc, cancellationToken).ConfigureAwait(false);
@@ -142,49 +125,8 @@ namespace Microsoft.Interop.Analyzers
                     .WithIsExtern(false)
                     .WithPartial(true));
 
-            if (!usePreprocessorDefines)
-            {
-                // Replace the original method with the updated one
-                editor.ReplaceNode(methodSyntax, generatedDeclaration);
-            }
-            else
-            {
-                // #if DLLIMPORTGENERATOR_ENABLED
-                generatedDeclaration = generatedDeclaration.WithLeadingTrivia(
-                    generatedDeclaration.GetLeadingTrivia()
-                        .AddRange(new[] {
-                            SyntaxFactory.Trivia(SyntaxFactory.IfDirectiveTrivia(SyntaxFactory.IdentifierName("DLLIMPORTGENERATOR_ENABLED"), isActive: true, branchTaken: true, conditionValue: true)),
-                            SyntaxFactory.ElasticMarker
-                        }));
-
-                // #else
-                generatedDeclaration = generatedDeclaration.WithTrailingTrivia(
-                    generatedDeclaration.GetTrailingTrivia()
-                        .AddRange(new[] {
-                            SyntaxFactory.Trivia(SyntaxFactory.ElseDirectiveTrivia(isActive: false, branchTaken: false)),
-                            SyntaxFactory.ElasticMarker
-                        }));
-
-                // Sort attribute arguments so that GeneratedDllImport and DllImport match
-                MethodDeclarationSyntax updatedDeclaration = (MethodDeclarationSyntax)generator.ReplaceNode(methodSyntax, dllImportSyntax, SortDllImportAttributeArguments(dllImportSyntax, generator));
-
-                // Remove existing leading trivia - it will be on the GeneratedDllImport method
-                updatedDeclaration = updatedDeclaration.WithLeadingTrivia();
-
-                // #endif
-                updatedDeclaration = updatedDeclaration.WithTrailingTrivia(
-                    methodSyntax.GetTrailingTrivia()
-                        .AddRange(new[] {
-                            SyntaxFactory.Trivia(SyntaxFactory.EndIfDirectiveTrivia(isActive: true)),
-                            SyntaxFactory.ElasticMarker
-                        }));
-
-                // Add the GeneratedDllImport method
-                editor.InsertBefore(methodSyntax, generatedDeclaration);
-
-                // Replace the original method with the updated DllImport method
-                editor.ReplaceNode(methodSyntax, updatedDeclaration);
-            }
+            // Replace the original method with the updated one
+            editor.ReplaceNode(methodSyntax, generatedDeclaration);
 
             return editor.GetChangedDocument();
         }
diff --git a/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.Designer.cs b/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.Designer.cs
index 28352565c85..744f1b611be 100644
--- a/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.Designer.cs
+++ b/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.Designer.cs
@@ -79,7 +79,7 @@ namespace Microsoft.Interop {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to When constructor taking a Span&lt;byte&gt; is specified on the native type, the type must also have a public integer constant named BufferSize to provide the size of the caller-allocated buffer..
+        ///   Looks up a localized string similar to When a constructor taking a Span&lt;byte&gt; is specified on the native type, the type must also have a public integer constant named BufferSize to provide the size of the caller-allocated buffer..
         /// </summary>
         internal static string CallerAllocConstructorMustHaveBufferSizeConstantDescription {
             get {
@@ -223,29 +223,29 @@ namespace Microsoft.Interop {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Use &apos;GeneratedDllImportAttribute&apos; instead of &apos;DllImportAttribute&apos; to generate P/Invoke marshalling code at compile time.
+        ///   Looks up a localized string similar to Convert to &apos;GeneratedDllImport&apos;.
         /// </summary>
-        internal static string ConvertToGeneratedDllImportDescription {
+        internal static string ConvertToGeneratedDllImport {
             get {
-                return ResourceManager.GetString("ConvertToGeneratedDllImportDescription", resourceCulture);
+                return ResourceManager.GetString("ConvertToGeneratedDllImport", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Mark the method &apos;{0}&apos; with &apos;GeneratedDllImportAttribute&apos; instead of &apos;DllImportAttribute&apos; to generate P/Invoke marshalling code at compile time.
+        ///   Looks up a localized string similar to Use &apos;GeneratedDllImportAttribute&apos; instead of &apos;DllImportAttribute&apos; to generate P/Invoke marshalling code at compile time.
         /// </summary>
-        internal static string ConvertToGeneratedDllImportMessage {
+        internal static string ConvertToGeneratedDllImportDescription {
             get {
-                return ResourceManager.GetString("ConvertToGeneratedDllImportMessage", resourceCulture);
+                return ResourceManager.GetString("ConvertToGeneratedDllImportDescription", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Convert to &apos;GeneratedDllImport&apos;.
+        ///   Looks up a localized string similar to Mark the method &apos;{0}&apos; with &apos;GeneratedDllImportAttribute&apos; instead of &apos;DllImportAttribute&apos; to generate P/Invoke marshalling code at compile time.
         /// </summary>
-        internal static string ConvertToGeneratedDllImportNoPreprocessor {
+        internal static string ConvertToGeneratedDllImportMessage {
             get {
-                return ResourceManager.GetString("ConvertToGeneratedDllImportNoPreprocessor", resourceCulture);
+                return ResourceManager.GetString("ConvertToGeneratedDllImportMessage", resourceCulture);
             }
         }
         
@@ -268,15 +268,6 @@ namespace Microsoft.Interop {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Convert to &apos;GeneratedDllImport&apos; under a preprocessor define.
-        /// </summary>
-        internal static string ConvertToGeneratedDllImportWithPreprocessor {
-            get {
-                return ResourceManager.GetString("ConvertToGeneratedDllImportWithPreprocessor", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to The specified parameter needs to be marshalled from managed to native, but the native type &apos;{0}&apos; does not support it..
         /// </summary>
         internal static string CustomTypeMarshallingManagedToNativeUnsupported {
diff --git a/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.resx b/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.resx
index a05f66fac1e..c3f3d9694fc 100644
--- a/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.resx
+++ b/src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Resources.resx
@@ -171,15 +171,15 @@
   <data name="ConstantAndElementCountInfoDisallowed" xml:space="preserve">
     <value>Only one of 'ConstantElementCount' or 'ElementCountInfo' may be used in a 'MarshalUsingAttribute' for a given 'ElementIndirectionLevel'</value>
   </data>
+  <data name="ConvertToGeneratedDllImport" xml:space="preserve">
+    <value>Convert to 'GeneratedDllImport'</value>
+  </data>
   <data name="ConvertToGeneratedDllImportDescription" xml:space="preserve">
     <value>Use 'GeneratedDllImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time</value>
   </data>
   <data name="ConvertToGeneratedDllImportMessage" xml:space="preserve">
     <value>Mark the method '{0}' with 'GeneratedDllImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time</value>
   </data>
-  <data name="ConvertToGeneratedDllImportNoPreprocessor" xml:space="preserve">
-    <value>Convert to 'GeneratedDllImport'</value>
-  </data>
   <data name="ConvertToGeneratedDllImportTitle" xml:space="preserve">
     <value>Use 'GeneratedDllImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time</value>
   </data>
@@ -187,9 +187,6 @@
     <value>Conversion to 'GeneratedDllImport' may change behavior and compatibility. See {0} for more information.</value>
     <comment>{0} is a documentation link</comment>
   </data>
-  <data name="ConvertToGeneratedDllImportWithPreprocessor" xml:space="preserve">
-    <value>Convert to 'GeneratedDllImport' under a preprocessor define</value>
-  </data>
   <data name="CustomTypeMarshallingManagedToNativeUnsupported" xml:space="preserve">
     <value>The specified parameter needs to be marshalled from managed to native, but the native type '{0}' does not support it.</value>
   </data>
diff --git a/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/ConvertToGeneratedDllImportFixerTests.cs b/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/ConvertToGeneratedDllImportFixerTests.cs
index 26d3914320e..a818ba851ee 100644
--- a/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/ConvertToGeneratedDllImportFixerTests.cs
+++ b/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/ConvertToGeneratedDllImportFixerTests.cs
@@ -17,10 +17,8 @@ namespace DllImportGenerator.UnitTests
     [ActiveIssue("https://github.com/dotnet/runtime/issues/60650", TestRuntimes.Mono)]
     public class ConvertToGeneratedDllImportFixerTests
     {
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task Basic(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task Basic()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -30,20 +28,7 @@ partial class Test
     public static extern int [|Method|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"")]
-    public static partial int {{|CS8795:Method|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"")]
-    public static extern int Method(out int ret);
-#endif
-}}"
-                : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -52,14 +37,11 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task Comments(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task Comments()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -75,32 +57,7 @@ partial class Test
     public static extern int [|Method2|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-    // P/Invoke
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(/*name*/""DoesNotExist"")] // comment
-    public static partial int {{|CS8795:Method1|}}(out int ret);
-#else
-    [DllImport(/*name*/""DoesNotExist"")] // comment
-    public static extern int Method1(out int ret);
-#endif
-
-    /** P/Invoke **/
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"") /*name*/]
-    // < ... >
-    public static partial int {{|CS8795:Method2|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"") /*name*/]
-    // < ... >
-    public static extern int Method2(out int ret);
-#endif
-}}"
-                : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -115,14 +72,11 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task MultipleAttributes(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task MultipleAttributes()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -137,32 +91,7 @@ partial class Test
     public static extern int [|Method2|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [System.ComponentModel.Description(""Test""), GeneratedDllImport(""DoesNotExist"")]
-    public static partial int {{|CS8795:Method1|}}(out int ret);
-#else
-    [System.ComponentModel.Description(""Test""), DllImport(""DoesNotExist"")]
-    public static extern int Method1(out int ret);
-#endif
-
-#if DLLIMPORTGENERATOR_ENABLED
-    [System.ComponentModel.Description(""Test"")]
-    [GeneratedDllImport(""DoesNotExist"")]
-    [return: MarshalAs(UnmanagedType.I4)]
-    public static partial int {{|CS8795:Method2|}}(out int ret);
-#else
-    [System.ComponentModel.Description(""Test"")]
-    [DllImport(""DoesNotExist"")]
-    [return: MarshalAs(UnmanagedType.I4)]
-    public static extern int Method2(out int ret);
-#endif
-}}"
-                : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -176,14 +105,11 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task NamedArguments(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task NamedArguments()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -196,27 +122,7 @@ partial class Test
     public static extern int [|Method2|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"", EntryPoint = ""Entry"")]
-    public static partial int {{|CS8795:Method1|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", EntryPoint = ""Entry"")]
-    public static extern int Method1(out int ret);
-#endif
-
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"", EntryPoint = ""Entry"", CharSet = CharSet.Unicode)]
-    public static partial int {{|CS8795:Method2|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", EntryPoint = ""Entry"", CharSet = CharSet.Unicode)]
-    public static extern int Method2(out int ret);
-#endif
-}}" : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -228,14 +134,11 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task RemoveableNamedArguments(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task RemoveableNamedArguments()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -248,27 +151,7 @@ partial class Test
     public static extern int [|Method2|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"", EntryPoint = ""Entry"")]
-    public static partial int {{|CS8795:Method1|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", EntryPoint = ""Entry"", BestFitMapping = false)]
-    public static extern int Method1(out int ret);
-#endif
-
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"")]
-    public static partial int {{|CS8795:Method2|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", ThrowOnUnmappableChar = false)]
-    public static extern int Method2(out int ret);
-#endif
-}}" : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -280,14 +163,11 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task ReplaceableExplicitPlatformDefaultCallingConvention(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task ReplaceableExplicitPlatformDefaultCallingConvention()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -297,19 +177,7 @@ partial class Test
     public static extern int [|Method1|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"", EntryPoint = ""Entry"")]
-    public static partial int {{|CS8795:Method1|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", EntryPoint = ""Entry"", CallingConvention = CallingConvention.Winapi)]
-    public static extern int Method1(out int ret);
-#endif
-}}" : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -318,20 +186,15 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
         [ConditionalTheory]
-        [InlineData(CallingConvention.Cdecl, typeof(CallConvCdecl), true)]
-        [InlineData(CallingConvention.Cdecl, typeof(CallConvCdecl), false)]
-        [InlineData(CallingConvention.StdCall, typeof(CallConvStdcall), true)]
-        [InlineData(CallingConvention.StdCall, typeof(CallConvStdcall), false)]
-        [InlineData(CallingConvention.ThisCall, typeof(CallConvThiscall), true)]
-        [InlineData(CallingConvention.ThisCall, typeof(CallConvThiscall), false)]
-        [InlineData(CallingConvention.FastCall, typeof(CallConvFastcall), true)]
-        [InlineData(CallingConvention.FastCall, typeof(CallConvFastcall), false)]
-        public async Task ReplaceableCallingConvention(CallingConvention callConv, Type callConvType, bool usePreprocessorDefines)
+        [InlineData(CallingConvention.Cdecl, typeof(CallConvCdecl))]
+        [InlineData(CallingConvention.StdCall, typeof(CallConvStdcall))]
+        [InlineData(CallingConvention.ThisCall, typeof(CallConvThiscall))]
+        [InlineData(CallingConvention.FastCall, typeof(CallConvFastcall))]
+        public async Task ReplaceableCallingConvention(CallingConvention callConv, Type callConvType)
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -341,20 +204,7 @@ partial class Test
     public static extern int [|Method1|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"", EntryPoint = ""Entry"")]
-    [UnmanagedCallConv(CallConvs = new System.Type[] {{ typeof({callConvType.FullName}) }})]
-    public static partial int {{|CS8795:Method1|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", EntryPoint = ""Entry"", CallingConvention = CallingConvention.{callConv})]
-    public static extern int Method1(out int ret);
-#endif
-}}" : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -364,14 +214,11 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
 
-        [ConditionalTheory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task PreferredAttributeOrder(bool usePreprocessorDefines)
+        [ConditionalFact]
+        public async Task PreferredAttributeOrder()
         {
             string source = @$"
 using System.Runtime.InteropServices;
@@ -381,19 +228,7 @@ partial class Test
     public static extern int [|Method|](out int ret);
 }}";
             // Fixed source will have CS8795 (Partial method must have an implementation) without generator run
-            string fixedSource = usePreprocessorDefines
-                ? @$"
-using System.Runtime.InteropServices;
-partial class Test
-{{
-#if DLLIMPORTGENERATOR_ENABLED
-    [GeneratedDllImport(""DoesNotExist"", EntryPoint = ""Entry"", CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]
-    public static partial int {{|CS8795:Method|}}(out int ret);
-#else
-    [DllImport(""DoesNotExist"", EntryPoint = ""Entry"", CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]
-    public static extern int Method(out int ret);
-#endif
-}}" : @$"
+            string fixedSource = @$"
 using System.Runtime.InteropServices;
 partial class Test
 {{
@@ -402,8 +237,7 @@ partial class Test
 }}";
             await VerifyCS.VerifyCodeFixAsync(
                 source,
-                fixedSource,
-                usePreprocessorDefines ? WithPreprocessorDefinesKey : NoPreprocessorDefinesKey);
+                fixedSource);
         }
     }
 }
diff --git a/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/Verifiers/CSharpCodeFixVerifier.cs b/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/Verifiers/CSharpCodeFixVerifier.cs
index d4ed1c02c5c..ae7fd894010 100644
--- a/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/Verifiers/CSharpCodeFixVerifier.cs
+++ b/src/libraries/System.Runtime.InteropServices/tests/DllImportGenerator.UnitTests/Verifiers/CSharpCodeFixVerifier.cs
@@ -44,22 +44,20 @@ namespace DllImportGenerator.UnitTests.Verifiers
         }
 
         /// <inheritdoc cref="CodeFixVerifier{TAnalyzer, TCodeFix, TTest, TVerifier}.VerifyCodeFixAsync(string, string)"/>
-        public static async Task VerifyCodeFixAsync(string source, string fixedSource, string? codeActionEquivalenceKey = null)
-            => await VerifyCodeFixAsync(source, DiagnosticResult.EmptyDiagnosticResults, fixedSource, codeActionEquivalenceKey);
+        public static async Task VerifyCodeFixAsync(string source, string fixedSource)
+            => await VerifyCodeFixAsync(source, DiagnosticResult.EmptyDiagnosticResults, fixedSource);
 
         /// <inheritdoc cref="CodeFixVerifier{TAnalyzer, TCodeFix, TTest, TVerifier}.VerifyCodeFixAsync(string, DiagnosticResult, string)"/>
-        public static async Task VerifyCodeFixAsync(string source, DiagnosticResult expected, string fixedSource, string? codeActionEquivalenceKey = null)
-            => await VerifyCodeFixAsync(source, new[] { expected }, fixedSource, codeActionEquivalenceKey);
+        public static async Task VerifyCodeFixAsync(string source, DiagnosticResult expected, string fixedSource)
+            => await VerifyCodeFixAsync(source, new[] { expected }, fixedSource);
 
         /// <inheritdoc cref="CodeFixVerifier{TAnalyzer, TCodeFix, TTest, TVerifier}.VerifyCodeFixAsync(string, DiagnosticResult[], string)"/>
-        public static async Task VerifyCodeFixAsync(string source, DiagnosticResult[] expected, string fixedSource, string? codeActionEquivalenceKey = null)
+        public static async Task VerifyCodeFixAsync(string source, DiagnosticResult[] expected, string fixedSource)
         {
             var test = new Test
             {
                 TestCode = source,
                 FixedCode = fixedSource,
-                CodeActionEquivalenceKey = codeActionEquivalenceKey,
-                CodeActionValidationMode = CodeActionValidationMode.None,
             };
 
             test.ExpectedDiagnostics.AddRange(expected);
@@ -117,9 +115,6 @@ namespace DllImportGenerator.UnitTests.Verifiers
                 });
             }
 
-            protected override ParseOptions CreateParseOptions()
-                => ((CSharpParseOptions)base.CreateParseOptions()).WithPreprocessorSymbols("DLLIMPORTGENERATOR_ENABLED");
-
             protected override async Task RunImplAsync(CancellationToken cancellationToken)
             {
                 try