Fix Decimal literal formatting in source generators

src/libraries/Common/src/SourceGenerators/CSharpSyntaxUtilities.cs

@@ -0,0 +1,59 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Globalization;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace SourceGenerators;
+
+internal static class CSharpSyntaxUtilities
+{
+    // Standard format for double and single on non-inbox frameworks to ensure value is round-trippable.
+    public const string DoubleFormatString = "G17";
+    public const string SingleFormatString = "G9";
+
+    // Format a literal in C# format -- works around https://github.com/dotnet/roslyn/issues/58705
+    public static string FormatLiteral(object? value, TypeRef type)
+    {
+        if (value == null)
+        {
+            return $"default({type.FullyQualifiedName})";
+        }
+
+        switch (value)
+        {
+            case string @string:
+                return SymbolDisplay.FormatLiteral(@string, quote: true); ;
+            case char @char:
+                return SymbolDisplay.FormatLiteral(@char, quote: true);
+            case double.NegativeInfinity:
+                return "double.NegativeInfinity";
+            case double.PositiveInfinity:
+                return "double.PositiveInfinity";
+            case double.NaN:
+                return "double.NaN";
+            case double @double:
+                return $"{@double.ToString(DoubleFormatString, CultureInfo.InvariantCulture)}D";
+            case float.NegativeInfinity:
+                return "float.NegativeInfinity";
+            case float.PositiveInfinity:
+                return "float.PositiveInfinity";
+            case float.NaN:
+                return "float.NaN";
+            case float @float:
+                return $"{@float.ToString(SingleFormatString, CultureInfo.InvariantCulture)}F";
+            case decimal @decimal:
+                // we do not need to specify a format string for decimal as it's default is round-trippable on all frameworks.
+                return $"{@decimal.ToString(CultureInfo.InvariantCulture)}M";
+            case bool @bool:
+                return @bool ? "true" : "false";
+            default:
+                // Assume this is a number.
+                return FormatNumber();
+        }
+
+        string FormatNumber() => $"({type.FullyQualifiedName})({Convert.ToString(value, CultureInfo.InvariantCulture)})";
+    }
+}

src/libraries/Microsoft.Extensions.Configuration.Binder/gen/ConfigurationBindingGenerator.Parser.cs

@@ -583,9 +583,8 @@ private ObjectSpec CreateObjectSpec(TypeParseInfo typeParseInfo)
                             AttributeData? attributeData = property.GetAttributes().FirstOrDefault(a => SymbolEqualityComparer.Default.Equals(a.AttributeClass, _typeSymbols.ConfigurationKeyNameAttribute));
                             string configKeyName = attributeData?.ConstructorArguments.FirstOrDefault().Value as string ?? propertyName;
 
-                            PropertySpec spec = new(property)
+                            PropertySpec spec = new(property, propertyTypeRef)
                             {
-                                TypeRef = propertyTypeRef,
                                 ConfigurationKeyName = configKeyName
                             };
 
@@ -617,9 +616,8 @@ private ObjectSpec CreateObjectSpec(TypeParseInfo typeParseInfo)
                         }
                         else
                         {
-                            ParameterSpec paramSpec = new ParameterSpec(parameter)
+                            ParameterSpec paramSpec = new ParameterSpec(parameter, propertySpec.TypeRef)
                             {
-                                TypeRef = propertySpec.TypeRef,
                                 ConfigurationKeyName = propertySpec.ConfigurationKeyName,
                             };
 

src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Microsoft.Extensions.Configuration.Binder.SourceGeneration.csproj

@@ -28,6 +28,7 @@
     <Compile Include="$(CoreLibSharedDir)System\Runtime\CompilerServices\RequiredMemberAttribute.cs" Link="Common\System\Runtime\CompilerServices\RequiredMemberAttribute.cs" />
     <Compile Include="$(CommonPath)\Roslyn\DiagnosticDescriptorHelper.cs" Link="Common\Roslyn\DiagnosticDescriptorHelper.cs" />
     <Compile Include="$(CommonPath)\Roslyn\GetBestTypeByMetadataName.cs" Link="Common\Roslyn\GetBestTypeByMetadataName.cs" />
+    <Compile Include="$(CommonPath)\SourceGenerators\CSharpSyntaxUtilities.cs" Link="Common\SourceGenerators\CSharpSyntaxUtilities.cs" />
     <Compile Include="$(CommonPath)\SourceGenerators\DiagnosticInfo.cs" Link="Common\SourceGenerators\DiagnosticInfo.cs" />
     <Compile Include="$(CommonPath)\SourceGenerators\ImmutableEquatableArray.cs" Link="Common\SourceGenerators\ImmutableEquatableArray.cs" />
     <Compile Include="$(CommonPath)\SourceGenerators\SourceWriter.cs" Link="Common\SourceGenerators\SourceWriter.cs" />

src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Specs/Members/MemberSpec.cs

@@ -9,17 +9,18 @@ namespace Microsoft.Extensions.Configuration.Binder.SourceGeneration
 {
     public abstract record MemberSpec
     {
-        public MemberSpec(ISymbol member)
+        public MemberSpec(ISymbol member, TypeRef typeRef)
         {
             Debug.Assert(member is IPropertySymbol or IParameterSymbol);
             Name = member.Name;
             DefaultValueExpr = "default";
+            TypeRef = typeRef;
         }
 
         public string Name { get; }
         public string DefaultValueExpr { get; protected set; }
 
-        public required TypeRef TypeRef { get; init; }
+        public TypeRef TypeRef { get; }
         public required string ConfigurationKeyName { get; init; }
 
         public abstract bool CanGet { get; }

src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Specs/Members/ParameterSpec.cs

@@ -1,24 +1,23 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Globalization;
+using System;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
+using SourceGenerators;
 
 namespace Microsoft.Extensions.Configuration.Binder.SourceGeneration
 {
     public sealed record ParameterSpec : MemberSpec
     {
-        public ParameterSpec(IParameterSymbol parameter) : base(parameter)
+        public ParameterSpec(IParameterSymbol parameter, TypeRef typeRef) : base(parameter, typeRef)
         {
             RefKind = parameter.RefKind;
 
             if (parameter.HasExplicitDefaultValue)
             {
-                string formatted = SymbolDisplay.FormatPrimitive(parameter.ExplicitDefaultValue!, quoteStrings: true, useHexadecimalNumbers: false);
-                if (formatted is not "null")
-                {
-                    DefaultValueExpr = formatted;
-                }
+                DefaultValueExpr = CSharpSyntaxUtilities.FormatLiteral(parameter.ExplicitDefaultValue, TypeRef);
             }
             else
             {

src/libraries/Microsoft.Extensions.Configuration.Binder/gen/Specs/Members/PropertySpec.cs

@@ -2,12 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.CodeAnalysis;
+using SourceGenerators;
 
 namespace Microsoft.Extensions.Configuration.Binder.SourceGeneration
 {
     public sealed record PropertySpec : MemberSpec
     {
-        public PropertySpec(IPropertySymbol property) : base(property)
+        public PropertySpec(IPropertySymbol property, TypeRef typeRef) : base(property, typeRef)
         {
             IMethodSymbol? setMethod = property.SetMethod;
             bool setterIsPublic = setMethod?.DeclaredAccessibility is Accessibility.Public;

src/libraries/Microsoft.Extensions.Configuration.Binder/tests/Common/ConfigurationBinderTests.TestClasses.cs

@@ -112,20 +112,45 @@ public ClassWhereParametersMatchPropertiesAndFields(string name, string address,
 
         public record RecordWhereParametersHaveDefaultValue(string Name, string Address, int Age = 42);
 
-        public record ClassWhereParametersHaveDefaultValue
+        public class ClassWhereParametersHaveDefaultValue
         {
             public string? Name { get; }
             public string Address { get; }
             public int Age { get; }
-
-            public ClassWhereParametersHaveDefaultValue(string? name, string address, int age = 42)
+            public float F { get; }
+            public double D { get; }
+            public decimal M { get; }
+            public StringComparison SC { get; }
+            public char C { get; }
+            public int? NAge { get; }
+            public float? NF { get; }
+            public double? ND { get; }
+            public decimal? NM { get; }
+            public StringComparison? NSC { get; }
+            public char? NC { get; }
+
+            public ClassWhereParametersHaveDefaultValue(string? name, string address, 
+                int age = 42, float f = 42.0f, double d = 3.14159, decimal m = 3.1415926535897932384626433M, StringComparison sc = StringComparison.Ordinal, char c = 'q',
+                int? nage = 42, float? nf = 42.0f, double? nd = 3.14159, decimal? nm = 3.1415926535897932384626433M, StringComparison? nsc = StringComparison.Ordinal, char? nc = 'q')
             {
                 Name = name;
                 Address = address;
                 Age = age;
+                F = f;
+                D = d;
+                M = m;
+                SC = sc;
+                C = c;
+                NAge = nage;
+                NF = nf;
+                ND = nd;
+                NM = nm;
+                NSC = nsc;
+                NC = nc;
             }
         }
 
+
         public class ClassWithPrimaryCtor(string color, int length)
         {
             public string Color { get; } = color;

src/libraries/Microsoft.Extensions.Configuration.Binder/tests/Common/ConfigurationBinderTests.cs

@@ -1064,6 +1064,17 @@ public void BindsToClassConstructorParametersWithDefaultValues()
             Assert.Equal("John", testOptions.ClassWhereParametersHaveDefaultValueProperty.Name);
             Assert.Equal("123, Abc St.", testOptions.ClassWhereParametersHaveDefaultValueProperty.Address);
             Assert.Equal(42, testOptions.ClassWhereParametersHaveDefaultValueProperty.Age);
+            Assert.Equal(42.0f, testOptions.ClassWhereParametersHaveDefaultValueProperty.F);
+            Assert.Equal(3.14159, testOptions.ClassWhereParametersHaveDefaultValueProperty.D);
+            Assert.Equal(3.1415926535897932384626433M, testOptions.ClassWhereParametersHaveDefaultValueProperty.M);
+            Assert.Equal(StringComparison.Ordinal, testOptions.ClassWhereParametersHaveDefaultValueProperty.SC);
+            Assert.Equal('q', testOptions.ClassWhereParametersHaveDefaultValueProperty.C);
+            Assert.Equal(42, testOptions.ClassWhereParametersHaveDefaultValueProperty.NAge);
+            Assert.Equal(42.0f, testOptions.ClassWhereParametersHaveDefaultValueProperty.NF);
+            Assert.Equal(3.14159, testOptions.ClassWhereParametersHaveDefaultValueProperty.ND);
+            Assert.Equal(3.1415926535897932384626433M, testOptions.ClassWhereParametersHaveDefaultValueProperty.NM);
+            Assert.Equal(StringComparison.Ordinal, testOptions.ClassWhereParametersHaveDefaultValueProperty.NSC);
+            Assert.Equal('q', testOptions.ClassWhereParametersHaveDefaultValueProperty.NC);
         }
 
         [Fact]

src/libraries/System.Text.Json/gen/JsonSourceGenerator.Emitter.cs

@@ -707,7 +707,7 @@ private static void GenerateCtorParamMetadataInitFunc(SourceWriter writer, strin
                             ParameterType = typeof({{spec.ParameterType.FullyQualifiedName}}),
                             Position = {{spec.ParameterIndex}},
                             HasDefaultValue = {{FormatBool(spec.HasDefaultValue)}},
-                            DefaultValue = {{FormatDefaultConstructorParameter(spec.DefaultValue, spec.ParameterType)}}
+                            DefaultValue = {{CSharpSyntaxUtilities.FormatLiteral(spec.DefaultValue, spec.ParameterType)}}
                         };
 
                         """);
@@ -1351,56 +1351,6 @@ private static string FormatJsonSerializerDefaults(JsonSerializerDefaults defaul
             private static string CreateTypeInfoMethodName(TypeGenerationSpec typeSpec)
                 => $"Create_{typeSpec.TypeInfoPropertyName}";
 
-            private static string FormatDefaultConstructorParameter(object? value, TypeRef type)
-            {
-                if (value == null)
-                {
-                    return $"default({type.FullyQualifiedName})";
-                }
-
-                if (type.TypeKind is TypeKind.Enum)
-                {
-                    // Return the numeric value.
-                    return FormatNumber();
-                }
-
-                switch (value)
-                {
-                    case string @string:
-                        return SymbolDisplay.FormatLiteral(@string, quote: true); ;
-                    case char @char:
-                        return SymbolDisplay.FormatLiteral(@char, quote: true);
-                    case double.NegativeInfinity:
-                        return "double.NegativeInfinity";
-                    case double.PositiveInfinity:
-                        return "double.PositiveInfinity";
-                    case double.NaN:
-                        return "double.NaN";
-                    case double @double:
-                        return $"({type.FullyQualifiedName})({@double.ToString(JsonConstants.DoubleFormatString, CultureInfo.InvariantCulture)})";
-                    case float.NegativeInfinity:
-                        return "float.NegativeInfinity";
-                    case float.PositiveInfinity:
-                        return "float.PositiveInfinity";
-                    case float.NaN:
-                        return "float.NaN";
-                    case float @float:
-                        return $"({type.FullyQualifiedName})({@float.ToString(JsonConstants.SingleFormatString, CultureInfo.InvariantCulture)})";
-                    case decimal.MaxValue:
-                        return "decimal.MaxValue";
-                    case decimal.MinValue:
-                        return "decimal.MinValue";
-                    case decimal @decimal:
-                        return @decimal.ToString(CultureInfo.InvariantCulture);
-                    case bool @bool:
-                        return FormatBool(@bool);
-                    default:
-                        // Assume this is a number.
-                        return FormatNumber();
-                }
-
-                string FormatNumber() => $"({type.FullyQualifiedName})({Convert.ToString(value, CultureInfo.InvariantCulture)})";
-            }
 
             private static string FormatDefaultConstructorExpr(TypeGenerationSpec typeSpec)
             {

src/libraries/System.Text.Json/gen/System.Text.Json.SourceGeneration.targets

@@ -30,6 +30,7 @@
     <Compile Include="$(CoreLibSharedDir)System\Runtime\CompilerServices\RequiredMemberAttribute.cs" Link="Common\System\Runtime\CompilerServices\RequiredMemberAttribute.cs" />
     <Compile Include="$(CommonPath)\Roslyn\DiagnosticDescriptorHelper.cs" Link="Common\Roslyn\DiagnosticDescriptorHelper.cs" />
     <Compile Include="$(CommonPath)\Roslyn\GetBestTypeByMetadataName.cs" Link="Common\Roslyn\GetBestTypeByMetadataName.cs" />
+    <Compile Include="$(CommonPath)\SourceGenerators\CSharpSyntaxUtilities.cs" Link="Common\SourceGenerators\CSharpSyntaxUtilities.cs" />
     <Compile Include="$(CommonPath)\SourceGenerators\DiagnosticInfo.cs" Link="Common\SourceGenerators\DiagnosticInfo.cs" />
     <Compile Include="$(CommonPath)\SourceGenerators\ImmutableEquatableArray.cs" Link="Common\SourceGenerators\ImmutableEquatableArray.cs" />
     <Compile Include="$(CommonPath)\SourceGenerators\SourceWriter.cs" Link="Common\SourceGenerators\SourceWriter.cs" />

src/libraries/System.Text.Json/tests/Common/ConstructorTests/ConstructorTests.ParameterMatching.cs

@@ -1602,6 +1602,14 @@ public class ClassWithIgnoredPropertyDefaultParam
             public ClassWithIgnoredPropertyDefaultParam(int x, int y = 5) => (X, Y) = (x, y);
         }
 
+        [Fact]
+        public async Task TestClassWithManyDefaultParams()
+        {
+            string json = "{}";
+            Class_With_Parameters_Default_Values result = await Serializer.DeserializeWrapper<Class_With_Parameters_Default_Values>(json);
+            result.Verify();
+        }
+
         [Fact]
         public async Task TestClassWithCustomConverterOnCtorParameter_ShouldPassCorrectTypeToConvertParameter()
         {

src/libraries/System.Text.Json/tests/Common/TestClasses/TestClasses.Constructor.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Collections.Immutable;
@@ -1972,6 +1973,61 @@ public void VerifyMinimal()
             MyTuple.Item4.Verify();
         }
     }
+    public class Class_With_Parameters_Default_Values
+    {
+        public int I { get; }
+        public float F { get; }
+        public double D { get; }
+        public decimal M { get; }
+        public StringComparison SC { get; }
+        public char C { get; }
+        public int? NI { get; }
+        public float? NF { get; }
+        public double? ND { get; }
+        public decimal? NM { get; }
+        public StringComparison? NSC { get; }
+        public char? NC { get; }
+
+        public Class_With_Parameters_Default_Values(
+                int i = 21, float f = 42.0f, double d = 3.14159, decimal m = 3.1415926535897932384626433M, StringComparison sc = StringComparison.Ordinal, char c = 'q',
+                int? ni = 21, float? nf = 42.0f, double? nd = 3.14159, decimal? nm = 3.1415926535897932384626433M, StringComparison? nsc = StringComparison.Ordinal, char? nc = 'q')
+        {
+            I = i;
+            F = f;
+            D = d;
+            M = m;
+            SC = sc;
+            C = c;
+            NI = ni;
+            NF = nf;
+            ND = nd;
+            NM = nm;
+            NSC = nsc;
+            NC = nc;
+        }
+
+        public void Initialize() { }
+
+        public static readonly string s_json = @"{}";
+
+        public static readonly byte[] s_data = Encoding.UTF8.GetBytes(s_json);
+
+        public void Verify()
+        {
+            Assert.Equal(21, I);
+            Assert.Equal(42.0f, F);
+            Assert.Equal(3.14159, D);
+            Assert.Equal(3.1415926535897932384626433M, M);
+            Assert.Equal(StringComparison.Ordinal, SC);
+            Assert.Equal('q', C);
+            Assert.Equal(21, NI);
+            Assert.Equal(42.0f, NF);
+            Assert.Equal(3.14159, ND);
+            Assert.Equal(3.1415926535897932384626433M, NM);
+            Assert.Equal(StringComparison.Ordinal, NSC);
+            Assert.Equal('q', NC);
+        }
+    }
 
     public class Point_MembersHave_JsonPropertyName : ITestClass
     {

src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/ConstructorTests.cs

@@ -112,6 +112,7 @@ protected ConstructorTests_Metadata(JsonSerializerWrapper stringWrapper)
         [JsonSerializable(typeof(SimpleClassWithParameterizedCtor_Derived_GenericIDictionary_ObjectExt))]
         [JsonSerializable(typeof(Point_MembersHave_JsonInclude))]
         [JsonSerializable(typeof(ClassWithFiveArgs_MembersHave_JsonNumberHandlingAttributes))]
+        [JsonSerializable(typeof(Class_With_Parameters_Default_Values))]
         [JsonSerializable(typeof(Point_MembersHave_JsonPropertyName))]
         [JsonSerializable(typeof(Point_MembersHave_JsonConverter))]
         [JsonSerializable(typeof(Point_MembersHave_JsonIgnore))]
@@ -260,6 +261,7 @@ public ConstructorTests_Default(JsonSerializerWrapper jsonSerializer) : base(jso
         [JsonSerializable(typeof(SimpleClassWithParameterizedCtor_Derived_GenericIDictionary_ObjectExt))]
         [JsonSerializable(typeof(Point_MembersHave_JsonInclude))]
         [JsonSerializable(typeof(ClassWithFiveArgs_MembersHave_JsonNumberHandlingAttributes))]
+        [JsonSerializable(typeof(Class_With_Parameters_Default_Values))]
         [JsonSerializable(typeof(Point_MembersHave_JsonPropertyName))]
         [JsonSerializable(typeof(Point_MembersHave_JsonConverter))]
         [JsonSerializable(typeof(Point_MembersHave_JsonIgnore))]