DateConsts

Author: GrahamTheCoder

CodeConverter/CSharp/ExpressionNodeVisitor.cs

@@ -924,25 +924,30 @@ public override async Task<CSharpSyntaxNode> VisitParameter(VBSyntax.ParameterSy
 
             EqualsValueClauseSyntax @default = null;
             if (node.Default != null) {
-                if (node.Default.Value is VBSyntax.LiteralExpressionSyntax les && les.Token.Value is DateTime dt) {
-                    var dateTimeAsLongCsLiteral = LiteralConversions.GetLiteralExpression(dt.Ticks, dt.Ticks + "L");
-                    var dateTimeArg = CommonConversions.CreateAttributeArgumentList(SyntaxFactory.AttributeArgument(dateTimeAsLongCsLiteral));
-                    _extraUsingDirectives.Add("System.Runtime.InteropServices");
-                    _extraUsingDirectives.Add("System.Runtime.CompilerServices");
-                    var optionalDateTimeAttributes = new[] {
-                        SyntaxFactory.Attribute(SyntaxFactory.ParseName("Optional")),
-                        SyntaxFactory.Attribute(SyntaxFactory.ParseName("DateTimeConstant"), dateTimeArg)
+                var defaultValue = node.Default.Value.SkipParens();
+                if (_semanticModel.GetTypeInfo(defaultValue).Type?.SpecialType == SpecialType.System_DateTime) {
+                    var constant = _semanticModel.GetConstantValue(defaultValue);
+                    if (constant.HasValue && constant.Value is DateTime dt) {
+                        var dateTimeAsLongCsLiteral = CommonConversions.Literal(dt.Ticks)
+                            .WithTrailingTrivia(SyntaxFactory.ParseTrailingTrivia($"/* {defaultValue} */"));
+                        var dateTimeArg = CommonConversions.CreateAttributeArgumentList(SyntaxFactory.AttributeArgument(dateTimeAsLongCsLiteral));
+                        _extraUsingDirectives.Add("System.Runtime.InteropServices");
+                        _extraUsingDirectives.Add("System.Runtime.CompilerServices");
+                        var optionalDateTimeAttributes = new[] {
+                        SyntaxFactory.Attribute(SyntaxFactory.IdentifierName("Optional")),
+                        SyntaxFactory.Attribute(SyntaxFactory.IdentifierName("DateTimeConstant"), dateTimeArg)
                     };
-                    attributes.Insert(0,
-                        SyntaxFactory.AttributeList(SyntaxFactory.SeparatedList(optionalDateTimeAttributes)));
+                        attributes.Insert(0,
+                            SyntaxFactory.AttributeList(SyntaxFactory.SeparatedList(optionalDateTimeAttributes)));
+                    }
                 } else if (node.Modifiers.Any(m => m.IsKind(VBasic.SyntaxKind.ByRefKeyword))) {
                     var defaultExpression = (ExpressionSyntax)await node.Default.Value.AcceptAsync(TriviaConvertingExpressionVisitor);
                     var arg = CommonConversions.CreateAttributeArgumentList(SyntaxFactory.AttributeArgument(defaultExpression));
                     _extraUsingDirectives.Add("System.Runtime.InteropServices");
                     _extraUsingDirectives.Add("System.Runtime.CompilerServices");
                     var optionalAttributes = new[] {
-                        SyntaxFactory.Attribute(SyntaxFactory.ParseName("Optional")),
-                        SyntaxFactory.Attribute(SyntaxFactory.ParseName("DefaultParameterValue"), arg)
+                        SyntaxFactory.Attribute(SyntaxFactory.IdentifierName("Optional")),
+                        SyntaxFactory.Attribute(SyntaxFactory.IdentifierName("DefaultParameterValue"), arg)
                     };
                     attributes.Insert(0,
                         SyntaxFactory.AttributeList(SyntaxFactory.SeparatedList(optionalAttributes)));

Tests/CSharp/ExpressionTests/ExpressionTests.cs

@@ -43,7 +43,7 @@ End Sub
 
 internal partial class TestClass
 {
-    private void TestMethod([Optional, DateTimeConstant(599266080000000000L)] DateTime date)
+    private void TestMethod([Optional, DateTimeConstant(599266080000000000/* #1/1/1900# */)] DateTime date)
     {
         var rslt = DateTime.Parse(""1900-01-01"");
         var rslt2 = DateTime.Parse(""2002-08-13 12:14:00"");
@@ -54,6 +54,31 @@ private void TestMethod([Optional, DateTimeConstant(599266080000000000L)] DateTi
 BC32024: Default values cannot be supplied for parameters that are not declared 'Optional'.");
         }
 
+        [Fact]
+        public async Task DateConsts()
+        {
+            await TestConversionVisualBasicToCSharp(@"Public Class Issue213
+    Const x As Date = #1990-1-1#
+
+    Private Sub Y(Optional ByVal opt As Date = x)
+    End Sub
+End Class", @"using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+public partial class Issue213
+{
+    private const DateTime x = DateTime.Parse(""1990-01-01"");
+
+    private void Y([Optional, DateTimeConstant(627667488000000000/* Global.Issue213.x */)] DateTime opt)
+    {
+    }
+}
+2 target compilation errors:
+CS0283: The type 'DateTime' cannot be declared const
+CS0133: The expression being assigned to 'Issue213.x' must be constant");
+        }
+
         [Fact]
         public async Task NullInlineRefArgument()
         {