Drop redundant own-namespace qualifier from generated ctor params

Enum-typed constructor parameters were emitted via SymbolDisplayFormat.FullyQualifiedFormat so
that an enum in another namespace resolves without a using. For enums declared in the same namespace
as the generated file (ICSharpCode.Decompiler.CSharp.Syntax) that produced a redundant
global::ICSharpCode.Decompiler.CSharp.Syntax. prefix, e.g. 'global::...Syntax.ClassType classType'.
The prefix is now stripped for the file's own namespace while cross-namespace enums stay qualified.
The global:: on Identifier.Create in NameSlot setters is deliberately kept: those run in expression
position where a string property literally named 'Identifier' (e.g. SimpleType) would otherwise
shadow the type.

Assisted-by: Claude:claude-opus-4-8:Claude Code

ICSharpCode.Decompiler.Generators/DecompilerSyntaxTreeGenerator.cs

@@ -167,7 +167,7 @@ internal class DecompilerSyntaxTreeGenerator : IIncrementalGenerator
 			if (property.Type.TypeKind == TypeKind.Enum && property.SetMethod != null && !property.IsStatic)
 			{
 				ctorParams ??= new();
-				ctorParams.Add((property.Name, property.Type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat), "", false, false));
+				ctorParams.Add((property.Name, CtorParamTypeName(property.Type), "", false, false));
 			}
 		}
 
@@ -184,6 +184,17 @@ internal class DecompilerSyntaxTreeGenerator : IIncrementalGenerator
 	// rules do not apply.
 	static string FieldName(string propertyName) => "slot_" + propertyName;
 
+	// Type name for an enum-typed constructor parameter. Fully-qualified so an enum in another
+	// namespace resolves without a using, minus the generated file's own namespace prefix, which is
+	// redundant there. Used only in parameter-type position, so no member-name shadowing applies
+	// (unlike Identifier.Create in NameSlot setters, which must stay global::-qualified).
+	static string CtorParamTypeName(ITypeSymbol type)
+	{
+		const string ownNamespacePrefix = "global::ICSharpCode.Decompiler.CSharp.Syntax.";
+		string name = type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
+		return name.StartsWith(ownNamespacePrefix) ? name.Substring(ownNamespacePrefix.Length) : name;
+	}
+
 	void WriteGeneratedMembers(SourceProductionContext context, AstNodeAdditions source)
 	{
 		var builder = new StringBuilder();