Restore parameter lists of parameterized properties in signatures

The main tree, tooltips, and search results once showed the parameter
list of a parameterized property; the ambience lost that when property
rendering went through the converted AST node, whose C# property syntax
cannot carry parameters. Take the parameter list from the symbol
instead and render it in parentheses (matching VB.NET usage syntax and
distinguishing these properties from indexers).

Assisted-by: Claude:claude-fable-5:Claude Code

ICSharpCode.Decompiler.Tests/Output/CSharpAmbienceTests.cs

@@ -374,6 +374,25 @@ namespace ICSharpCode.Decompiler.Tests.Output
 			ambience.ConversionFlags = ConversionFlags.All & ~(ConversionFlags.ShowBody | ConversionFlags.PlaceReturnTypeAfterParameterList);
 			Assert.That(ambience.ConvertSymbol(indexer), Is.EqualTo("public dynamic dynamic.this[int]"));
 		}
+
+		[Test]
+		public void ParameterizedProperty()
+		{
+			// A named property with parameters (VB.NET parameterized property); C# has no
+			// syntax for it, but signature surfaces show the parameter list in parentheses.
+			var property = new FakeProperty(compilation) {
+				Name = "Data",
+				ReturnType = compilation.FindType(KnownTypeCode.Int32),
+				DeclaringType = SpecialType.Dynamic,
+				Parameters = new IParameter[] { new DefaultParameter(compilation.FindType(KnownTypeCode.Int32), "index") },
+			};
+
+			ambience.ConversionFlags = ILSpyMainTreeViewMemberFlags;
+			Assert.That(ambience.ConvertSymbol(property), Is.EqualTo("Data(int) : int"));
+
+			ambience.ConversionFlags = ConversionFlags.All & ~(ConversionFlags.ShowBody | ConversionFlags.PlaceReturnTypeAfterParameterList);
+			Assert.That(ambience.ConvertSymbol(property), Is.EqualTo("public int dynamic.Data(int index)"));
+		}
 		#endregion
 
 		#region Test types

ICSharpCode.Decompiler/CSharp/OutputVisitor/CSharpAmbience.cs

@@ -148,6 +148,12 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 					var subst = new TypeParameterSubstitution(extensionGroup.TypeParameters, null);
 					parameters = extensionGroup.Marker.Specialize(subst).Parameters.Select(p => astBuilder.ConvertParameter(p));
 				}
+				else if (symbol is IProperty { SymbolKind: SymbolKind.Property } parameterizedProperty)
+				{
+					// C# property syntax has no parameter list, so the converted node carries
+					// none; parameterized properties take theirs from the symbol.
+					parameters = parameterizedProperty.Parameters.Select(p => astBuilder.ConvertParameter(p));
+				}
 				else
 				{
 					parameters = node.GetChildren(Slots.Parameter);
@@ -256,6 +262,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 				case SymbolKind.Operator:
 				case SymbolKind.Constructor:
 				case SymbolKind.Destructor:
+				case SymbolKind.Property when ((IProperty)e).Parameters.Count > 0:
 					return (ConversionFlags & ConversionFlags.ShowParameterList) != 0;
 				default:
 					return false;