Update DllImportGenerator style to match repo conventions

src/libraries/Common/src/System/Runtime/InteropServices/ArrayMarshaller.cs

@@ -26,7 +26,7 @@ unsafe ref struct ArrayMarshaller<T>
         private IntPtr _allocatedMemory;
 
         public ArrayMarshaller(int sizeOfNativeElement)
-            :this()
+            : this()
         {
             _sizeOfNativeElement = sizeOfNativeElement;
         }

src/libraries/Common/src/System/Runtime/InteropServices/GeneratedMarshallingAttribute.cs

@@ -57,7 +57,7 @@ public MarshalUsingAttribute()
         }
 
         public MarshalUsingAttribute(Type nativeType)
-            :this()
+            : this()
         {
             NativeType = nativeType;
         }

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Analyzers/ConvertToGeneratedDllImportFixer.cs

@@ -55,8 +55,7 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
                 return;
 
             // Make sure the method has the DllImportAttribute
-            AttributeData? dllImportAttr;
-            if (!TryGetAttribute(methodSymbol, dllImportAttrType, out dllImportAttr))
+            if (!TryGetAttribute(methodSymbol, dllImportAttrType, out AttributeData? dllImportAttr))
                 return;
 
             // Register code fixes with two options for the fix - using preprocessor or not.

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Analyzers/ManualTypeMarshallingAnalyzer.cs

@@ -225,13 +225,13 @@ private void PrepareForAnalysis(CompilationStartAnalysisContext context)
 
         private class PerCompilationAnalyzer
         {
-            private readonly INamedTypeSymbol GeneratedMarshallingAttribute;
-            private readonly INamedTypeSymbol BlittableTypeAttribute;
-            private readonly INamedTypeSymbol NativeMarshallingAttribute;
-            private readonly INamedTypeSymbol MarshalUsingAttribute;
-            private readonly INamedTypeSymbol GenericContiguousCollectionMarshallerAttribute;
-            private readonly INamedTypeSymbol SpanOfByte;
-            private readonly INamedTypeSymbol StructLayoutAttribute;
+            private readonly INamedTypeSymbol _generatedMarshallingAttribute;
+            private readonly INamedTypeSymbol _blittableTypeAttribute;
+            private readonly INamedTypeSymbol _nativeMarshallingAttribute;
+            private readonly INamedTypeSymbol _marshalUsingAttribute;
+            private readonly INamedTypeSymbol _genericContiguousCollectionMarshallerAttribute;
+            private readonly INamedTypeSymbol _spanOfByte;
+            private readonly INamedTypeSymbol _structLayoutAttribute;
 
             public PerCompilationAnalyzer(INamedTypeSymbol generatedMarshallingAttribute,
                                           INamedTypeSymbol blittableTypeAttribute,
@@ -241,13 +241,13 @@ public PerCompilationAnalyzer(INamedTypeSymbol generatedMarshallingAttribute,
                                           INamedTypeSymbol spanOfByte,
                                           INamedTypeSymbol structLayoutAttribute)
             {
-                GeneratedMarshallingAttribute = generatedMarshallingAttribute;
-                BlittableTypeAttribute = blittableTypeAttribute;
-                NativeMarshallingAttribute = nativeMarshallingAttribute;
-                MarshalUsingAttribute = marshalUsingAttribute;
-                GenericContiguousCollectionMarshallerAttribute = genericContiguousCollectionMarshallerAttribute;
-                SpanOfByte = spanOfByte;
-                StructLayoutAttribute = structLayoutAttribute;
+                _generatedMarshallingAttribute = generatedMarshallingAttribute;
+                _blittableTypeAttribute = blittableTypeAttribute;
+                _nativeMarshallingAttribute = nativeMarshallingAttribute;
+                _marshalUsingAttribute = marshalUsingAttribute;
+                _genericContiguousCollectionMarshallerAttribute = genericContiguousCollectionMarshallerAttribute;
+                _spanOfByte = spanOfByte;
+                _structLayoutAttribute = structLayoutAttribute;
             }
 
             public void AnalyzeTypeDefinition(SymbolAnalysisContext context)
@@ -258,17 +258,17 @@ public void AnalyzeTypeDefinition(SymbolAnalysisContext context)
                 AttributeData? nativeMarshallingAttributeData = null;
                 foreach (var attr in type.GetAttributes())
                 {
-                    if (SymbolEqualityComparer.Default.Equals(attr.AttributeClass, GeneratedMarshallingAttribute))
+                    if (SymbolEqualityComparer.Default.Equals(attr.AttributeClass, _generatedMarshallingAttribute))
                     {
                         // If the type has the GeneratedMarshallingAttribute,
                         // we let the source generator handle error checking.
                         return;
                     }
-                    else if (SymbolEqualityComparer.Default.Equals(attr.AttributeClass, BlittableTypeAttribute))
+                    else if (SymbolEqualityComparer.Default.Equals(attr.AttributeClass, _blittableTypeAttribute))
                     {
                         blittableTypeAttributeData = attr;
                     }
-                    else if (SymbolEqualityComparer.Default.Equals(attr.AttributeClass, NativeMarshallingAttribute))
+                    else if (SymbolEqualityComparer.Default.Equals(attr.AttributeClass, _nativeMarshallingAttribute))
                     {
                         nativeMarshallingAttributeData = attr;
                     }
@@ -281,7 +281,7 @@ public void AnalyzeTypeDefinition(SymbolAnalysisContext context)
                             CannotHaveMultipleMarshallingAttributesRule,
                             type.ToDisplayString()));
                 }
-                else if (blittableTypeAttributeData is not null && (!type.HasOnlyBlittableFields() || type.IsAutoLayout(StructLayoutAttribute)))
+                else if (blittableTypeAttributeData is not null && (!type.HasOnlyBlittableFields() || type.IsAutoLayout(_structLayoutAttribute)))
                 {
                     context.ReportDiagnostic(
                         blittableTypeAttributeData.CreateDiagnostic(
@@ -290,7 +290,7 @@ public void AnalyzeTypeDefinition(SymbolAnalysisContext context)
                 }
                 else if (nativeMarshallingAttributeData is not null)
                 {
-                    AnalyzeNativeMarshalerType(context, type, nativeMarshallingAttributeData, isNativeMarshallingAttribute:true);
+                    AnalyzeNativeMarshalerType(context, type, nativeMarshallingAttributeData, isNativeMarshallingAttribute: true);
                 }
             }
 
@@ -307,7 +307,7 @@ private bool HasMultipleMarshallingAttributes(AttributeData? blittableTypeAttrib
 
             public void AnalyzeElement(SymbolAnalysisContext context)
             {
-                AttributeData? attrData = context.Symbol.GetAttributes().FirstOrDefault(attr => SymbolEqualityComparer.Default.Equals(MarshalUsingAttribute, attr.AttributeClass));
+                AttributeData? attrData = context.Symbol.GetAttributes().FirstOrDefault(attr => SymbolEqualityComparer.Default.Equals(_marshalUsingAttribute, attr.AttributeClass));
                 if (attrData is not null)
                 {
                     if (context.Symbol is IParameterSymbol param)
@@ -324,7 +324,7 @@ public void AnalyzeElement(SymbolAnalysisContext context)
             public void AnalyzeReturnType(SymbolAnalysisContext context)
             {
                 var method = (IMethodSymbol)context.Symbol;
-                AttributeData? attrData = method.GetReturnTypeAttributes().FirstOrDefault(attr => SymbolEqualityComparer.Default.Equals(MarshalUsingAttribute, attr.AttributeClass));
+                AttributeData? attrData = method.GetReturnTypeAttributes().FirstOrDefault(attr => SymbolEqualityComparer.Default.Equals(_marshalUsingAttribute, attr.AttributeClass));
                 if (attrData is not null)
                 {
                     AnalyzeNativeMarshalerType(context, method.ReturnType, attrData, isNativeMarshallingAttribute: false);
@@ -364,12 +364,12 @@ private void AnalyzeNativeMarshalerType(SymbolAnalysisContext context, ITypeSymb
                 DiagnosticDescriptor requiredShapeRule = NativeTypeMustHaveRequiredShapeRule;
 
                 ManualTypeMarshallingHelper.NativeTypeMarshallingVariant variant = ManualTypeMarshallingHelper.NativeTypeMarshallingVariant.Standard;
-                if (marshalerType.GetAttributes().Any(a => SymbolEqualityComparer.Default.Equals(GenericContiguousCollectionMarshallerAttribute, a.AttributeClass)))
+                if (marshalerType.GetAttributes().Any(a => SymbolEqualityComparer.Default.Equals(_genericContiguousCollectionMarshallerAttribute, a.AttributeClass)))
                 {
                     variant = ManualTypeMarshallingHelper.NativeTypeMarshallingVariant.ContiguousCollection;
                     requiredShapeRule = CollectionNativeTypeMustHaveRequiredShapeRule;
                     if (!ManualTypeMarshallingHelper.TryGetManagedValuesProperty(marshalerType, out _)
-                        || !ManualTypeMarshallingHelper.HasNativeValueStorageProperty(marshalerType, SpanOfByte))
+                        || !ManualTypeMarshallingHelper.HasNativeValueStorageProperty(marshalerType, _spanOfByte))
                     {
                         context.ReportDiagnostic(
                             GetDiagnosticLocations(context, marshalerType, nativeMarshalerAttributeData).CreateDiagnostic(
@@ -425,7 +425,7 @@ private void AnalyzeNativeMarshalerType(SymbolAnalysisContext context, ITypeSymb
 
                     hasConstructor = hasConstructor || ManualTypeMarshallingHelper.IsManagedToNativeConstructor(ctor, type, variant);
 
-                    if (!hasStackallocConstructor && ManualTypeMarshallingHelper.IsStackallocConstructor(ctor, type, SpanOfByte, variant))
+                    if (!hasStackallocConstructor && ManualTypeMarshallingHelper.IsStackallocConstructor(ctor, type, _spanOfByte, variant))
                     {
                         hasStackallocConstructor = true;
                         IFieldSymbol stackAllocSizeField = nativeType.GetMembers("StackBufferSize").OfType<IFieldSymbol>().FirstOrDefault();

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Comparers.cs

@@ -39,20 +39,20 @@ internal static class Comparers
     /// <typeparam name="T">The type of immutable array element.</typeparam>
     internal class ImmutableArraySequenceEqualComparer<T> : IEqualityComparer<ImmutableArray<T>>
     {
-        private readonly IEqualityComparer<T> elementComparer;
+        private readonly IEqualityComparer<T> _elementComparer;
 
         /// <summary>
         /// Creates an <see cref="ImmutableArraySequenceEqualComparer{T}"/> with a custom comparer for the elements of the collection.
         /// </summary>
         /// <param name="elementComparer">The comparer instance for the collection elements.</param>
         public ImmutableArraySequenceEqualComparer(IEqualityComparer<T> elementComparer)
         {
-            this.elementComparer = elementComparer;
+            _elementComparer = elementComparer;
         }
 
         public bool Equals(ImmutableArray<T> x, ImmutableArray<T> y)
         {
-            return x.SequenceEqual(y, elementComparer);
+            return x.SequenceEqual(y, _elementComparer);
         }
 
         public int GetHashCode(ImmutableArray<T> obj)
@@ -76,18 +76,18 @@ public int GetHashCode(SyntaxNode obj)
 
     internal class CustomValueTupleElementComparer<T, U> : IEqualityComparer<(T, U)>
     {
-        private readonly IEqualityComparer<T> item1Comparer;
-        private readonly IEqualityComparer<U> item2Comparer;
+        private readonly IEqualityComparer<T> _item1Comparer;
+        private readonly IEqualityComparer<U> _item2Comparer;
 
         public CustomValueTupleElementComparer(IEqualityComparer<T> item1Comparer, IEqualityComparer<U> item2Comparer)
         {
-            this.item1Comparer = item1Comparer;
-            this.item2Comparer = item2Comparer;
+            _item1Comparer = item1Comparer;
+            _item2Comparer = item2Comparer;
         }
 
         public bool Equals((T, U) x, (T, U) y)
         {
-            return item1Comparer.Equals(x.Item1, y.Item1) && item2Comparer.Equals(x.Item2, y.Item2);
+            return _item1Comparer.Equals(x.Item1, y.Item1) && _item2Comparer.Equals(x.Item2, y.Item2);
         }
 
         public int GetHashCode((T, U) obj)

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/Diagnostics/Events.cs

@@ -45,7 +45,7 @@ public static IDisposable SourceGenerationStartStop(int methodCount)
         [Event(StartSourceGenerationEventId, Level = EventLevel.Informational, Keywords = Keywords.SourceGeneration)]
         public void SourceGenerationStart(int methodCount)
         {
-            this.WriteEvent(StartSourceGenerationEventId, methodCount);
+            WriteEvent(StartSourceGenerationEventId, methodCount);
         }
 
         /// <summary>
@@ -54,7 +54,7 @@ public void SourceGenerationStart(int methodCount)
         [Event(StopSourceGenerationEventId, Level = EventLevel.Informational, Keywords = Keywords.SourceGeneration)]
         public void SourceGenerationStop()
         {
-            this.WriteEvent(StopSourceGenerationEventId);
+            WriteEvent(StopSourceGenerationEventId);
         }
 
         private class StartStopEvent : IDisposable

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/DllImportGenerator.cs

@@ -25,7 +25,7 @@ public sealed class DllImportGenerator : IIncrementalGenerator
         private const string GeneratedDllImport = nameof(GeneratedDllImport);
         private const string GeneratedDllImportAttribute = nameof(GeneratedDllImportAttribute);
 
-        private static readonly Version MinimumSupportedFrameworkVersion = new Version(5, 0);
+        private static readonly Version s_minimumSupportedFrameworkVersion = new Version(5, 0);
 
         internal sealed record IncrementalStubGenerationContext(DllImportStubContext StubContext, ImmutableArray<AttributeSyntax> ForwardedAttributes, GeneratedDllImportData DllImportData, ImmutableArray<Diagnostic> Diagnostics)
         {
@@ -57,10 +57,10 @@ public enum StepName
 
             public record ExecutedStepInfo(StepName Step, object Input);
 
-            private List<ExecutedStepInfo> executedSteps = new();
-            public IEnumerable<ExecutedStepInfo> ExecutedSteps => executedSteps;
+            private readonly List<ExecutedStepInfo> _executedSteps = new();
+            public IEnumerable<ExecutedStepInfo> ExecutedSteps => _executedSteps;
 
-            internal void RecordExecutedStep(ExecutedStepInfo step) => executedSteps.Add(step);
+            internal void RecordExecutedStep(ExecutedStepInfo step) => _executedSteps.Add(step);
         }
 
         /// <summary>
@@ -106,7 +106,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                             Diagnostic.Create(
                                 GeneratorDiagnostics.TargetFrameworkNotSupported,
                                 Location.None,
-                                MinimumSupportedFrameworkVersion.ToString(2)));
+                                s_minimumSupportedFrameworkVersion.ToString(2)));
                     }
                 });
 
@@ -294,7 +294,7 @@ private static bool IsSupportedTargetFramework(Compilation compilation, out Vers
                 // .NET Standard
                 "netstandard" => false,
                 // .NET Core (when version < 5.0) or .NET
-                "System.Runtime" or "System.Private.CoreLib" => version >= MinimumSupportedFrameworkVersion,
+                "System.Runtime" or "System.Private.CoreLib" => version >= s_minimumSupportedFrameworkVersion,
                 _ => false,
             };
         }

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/DllImportStubContext.cs

@@ -25,9 +25,9 @@ internal record StubEnvironment(
 
     internal sealed class DllImportStubContext : IEquatable<DllImportStubContext>
     {
-// We don't need the warnings around not setting the various
-// non-nullable fields/properties on this type in the constructor
-// since we always use a property initializer.
+        // We don't need the warnings around not setting the various
+        // non-nullable fields/properties on this type in the constructor
+        // since we always use a property initializer.
 #pragma warning disable 8618
         private DllImportStubContext()
         {

src/libraries/System.Runtime.InteropServices/gen/DllImportGenerator/ForwarderMarshallingGeneratorFactory.cs

@@ -9,8 +9,8 @@ namespace Microsoft.Interop
 {
     internal class ForwarderMarshallingGeneratorFactory : IMarshallingGeneratorFactory
     {
-        private static readonly Forwarder Forwarder = new Forwarder();
+        private static readonly Forwarder s_forwarder = new Forwarder();
 
-        public IMarshallingGenerator Create(TypePositionInfo info, StubCodeContext context) => Forwarder;
+        public IMarshallingGenerator Create(TypePositionInfo info, StubCodeContext context) => s_forwarder;
     }
 }