Add support for collection expressions in attributes (#69968)

dotnet · Sep 26, 2023 · b925063 · b925063
1 parent db312ba
commit b925063
Show file tree

Hide file tree

Showing 3 changed files with 508 additions and 9 deletions.
diff --git a/src/Analyzers/CSharp/Tests/UseCollectionExpression/UseCollectionExpressionForArrayTests.cs b/src/Analyzers/CSharp/Tests/UseCollectionExpression/UseCollectionExpressionForArrayTests.cs
@@ -1071,15 +1071,6 @@ public class XAttribute : System.Attribute
                     public XAttribute(int[] values) { }
                 }
                 """,
-            FixedState =
-                {
-                    // THis will tart working once https://github.com/dotnet/roslyn/issues/69133 is fixed.
-                    ExpectedDiagnostics =
-                    {
-                        // /0/Test0.cs(1,4): error CS0182: An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type
-                        DiagnosticResult.CompilerError("CS0182").WithSpan(1, 4, 1, 13),
-                    }
-                },
             LanguageVersion = LanguageVersion.CSharp12,
         }.RunAsync();
     }

diff --git a/src/Compilers/CSharp/Portable/Binder/Binder_Attributes.cs b/src/Compilers/CSharp/Portable/Binder/Binder_Attributes.cs
@@ -968,11 +968,21 @@ private TypedConstant VisitExpression(BoundExpression node, TypedConstantKind ty
                         return VisitTypeOfExpression((BoundTypeOfOperator)node, diagnostics, ref attrHasErrors, curArgumentHasErrors);
                     case BoundKind.ArrayCreation:
                         return VisitArrayCreation((BoundArrayCreation)node, diagnostics, ref attrHasErrors, curArgumentHasErrors);
+                    case BoundKind.CollectionExpressionSpreadElement:
+                        Binder.Error(diagnostics, ErrorCode.ERR_BadAttributeArgument, node.Syntax);
+                        return CreateTypedConstant(node, TypedConstantKind.Error, diagnostics, ref attrHasErrors, curArgumentHasErrors);
                     default:
                         return CreateTypedConstant(node, TypedConstantKind.Error, diagnostics, ref attrHasErrors, curArgumentHasErrors);
                 }
             }
 
+            private TypedConstant VisitArrayCollectionExpression(TypeSymbol type, BoundCollectionExpression collection, BindingDiagnosticBag diagnostics, ref bool attrHasErrors, bool curArgumentHasErrors)
+            {
+                var typedConstantKind = type.GetAttributeParameterTypedConstantKind(_binder.Compilation);
+                ImmutableArray<TypedConstant> elements = VisitArguments(collection.Elements, diagnostics, ref attrHasErrors, curArgumentHasErrors);
+                return CreateTypedConstant(collection, typedConstantKind, diagnostics, ref attrHasErrors, curArgumentHasErrors, arrayValue: elements);
+            }
+
             private TypedConstant VisitConversion(BoundConversion node, BindingDiagnosticBag diagnostics, ref bool attrHasErrors, bool curArgumentHasErrors)
             {
                 Debug.Assert(node.ConstantValueOpt == null);
@@ -989,6 +999,13 @@ private TypedConstant VisitConversion(BoundConversion node, BindingDiagnosticBag
                 var operand = node.Operand;
                 var operandType = operand.Type;
 
+                if (node.Conversion.IsCollectionExpression
+                    && node.Conversion.GetCollectionExpressionTypeKind(out _) == CollectionExpressionTypeKind.Array)
+                {
+                    Debug.Assert(type.IsSZArray());
+                    return VisitArrayCollectionExpression(type, (BoundCollectionExpression)operand, diagnostics, ref attrHasErrors, curArgumentHasErrors);
+                }
+
                 if ((object)type != null && operandType is object)
                 {
                     if (type.SpecialType == SpecialType.System_Object ||