run time:

- unboxing value types
- binding to CancellationToken
- overload resolution with Closure->System.Delegate

src/Peachpie.Runtime/Conversions.cs

@@ -5,7 +5,7 @@
 using System.Linq;
 using System.Reflection;
 using System.Text;
-using System.Threading.Tasks;
+using Pchp.Core.Dynamic;
 using Pchp.Core.Reflection;
 using Pchp.Core.Text;
 
@@ -1376,6 +1376,36 @@ public static DateTime ToDateTime(this PhpValue value)
         }
 
         #endregion
+
+        #region UnwrapStruct
+
+        /// <summary>
+        /// Given <typeparamref name="T"/> is a CLR value type (not a scalar PHP type!),
+        /// this method tries to unwrap <paramref name="value"/> to <typeparamref name="T"/>.
+        /// No conversion is performed. The method throws an exception is the value type does not match.
+        /// If <paramref name="value"/> is <c>NULL</c>, the method returns default of <typeparamref name="T"/>.
+        /// </summary>
+        public static T UnwrapStruct<T>(PhpValue value) where T : struct
+        {
+            switch (value.TypeCode)
+            {
+                case PhpTypeCode.Null: return default(T);
+                case PhpTypeCode.Alias: return UnwrapStruct<T>(value.Alias.Value);
+                case PhpTypeCode.Object:
+                    var obj = value.Object;
+
+                    if (obj is StructBox<T> box_t) return box_t.Value;
+                    if (obj is IStructBox box) return (T)box.BoxedValue; // throws
+
+                    return (T)obj; // throws if type does not match
+
+                default:
+                    // throws:
+                    return (T)value.ToClr();
+            }
+        }
+
+        #endregion
     }
 
     #endregion
@@ -1499,7 +1529,7 @@ public static double ToDouble(PhpValue value)
             PhpTypeCode.Null => null,
             _ => throw PhpException.TypeErrorException(string.Format(Resources.ErrResources.scalar_used_as_object, PhpVariable.GetTypeName(value))),
         };
-        
+
         public static object AsResource(PhpValue value) => value.TypeCode switch
         {
             PhpTypeCode.Object => value.Object as PhpResource ?? throw PhpException.TypeErrorException(),

src/Peachpie.Runtime/Dynamic/ConvertExpression.cs

@@ -6,8 +6,6 @@
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
-using System.Text;
-using System.Threading.Tasks;
 using Pchp.Core.Reflection;
 
 namespace Pchp.Core.Dynamic
@@ -126,9 +124,10 @@ public static Expression Bind(Expression arg, Type target, Expression ctx)
             // 
             if (target.IsValueType == false)
             {
-                Debug.Assert(typeof(Nullable<bool>).IsValueType);
-
-                return BindAsReferenceType(arg, target, ctx);
+                if (TryBindAsReferenceType(arg, target, ctx, out var expression))
+                {
+                    return expression;
+                }
             }
             else
             {
@@ -160,16 +159,16 @@ public static Expression Bind(Expression arg, Type target, Expression ctx)
                 }
             }
 
-            //// PhpValueConverter.Cast<T>( (PhpValue ) : T
-            //return Expression.Call(
-            //    typeof(PhpValueConverter).GetMethod("Cast", BindingFlags.Public | BindingFlags.Static).MakeGenericMethod(target),
-            //    BindToValue(arg));
-
-            //
-            return Expression.Block(
-                ThrowTypeError($"{arg.Type} -> {target}"),
-                BindDefault(target)
+            // Template: PhpValueConverter.Cast<T>( PhpValue ) : T
+            return Expression.Call(
+                Cache.Operators.Cast_PhpValue_T.MakeGenericMethod(target),
+                BindToValue(arg)
             );
+
+            //return Expression.Block(
+            //    ThrowTypeError($"{arg.Type} -> {target}"),
+            //    BindDefault(target)
+            //);
         }
 
         private static bool IsNullConstant(Expression arg)
@@ -687,13 +686,17 @@ static Expression BindAsObject(Expression expr)
             return Expression.Call(Cache.Operators.PhpValue_AsObjectOrThrow, BindToValue(expr));
         }
 
-        static Expression BindAsReferenceType(Expression expr, Type target, Expression ctx)
+        /// <summary>
+        /// Specialized conversion to a referenced type.
+        /// </summary>
+        static bool TryBindAsReferenceType(Expression expr, Type target, Expression ctx, out Expression expression)
         {
             Debug.Assert(expr.Type != typeof(PhpAlias));
 
             if (IsNullConstant(expr))
             {
-                return Expression.Constant(null, typeof(object));
+                expression = Expression.Constant(null, typeof(object));
+                return true;
             }
 
             // to System.Delegate,
@@ -702,9 +705,10 @@ static Expression BindAsReferenceType(Expression expr, Type target, Expression c
             {
                 // Template: PhpCallableToDelegate<target>.Get( BindAsCallable(expr), Context )
                 var callable = BindAsCallable(expr);
-                return Expression.Call(
+                expression = Expression.Call(
                     typeof(PhpCallableToDelegate<>).MakeGenericType(target).GetMethod("Get"),
                     callable, ctx);
+                return true;
             }
 
             //// from PhpValue:
@@ -723,10 +727,9 @@ static Expression BindAsReferenceType(Expression expr, Type target, Expression c
             //// just cast:
             //return Expression.Convert(expr, target);
 
-            // Template: PhpValueConverter.Cast<T>( PhpValue )
-            return Expression.Call(
-                    Cache.Operators.Cast_PhpValue_T.MakeGenericMethod(target),
-                    BindToValue(expr));
+            //
+            expression = null;
+            return false;
         }
 
         private static Expression BindAsArray(Expression expr, Type target)
@@ -913,6 +916,12 @@ public static Expression BindCost(Expression arg, Type target)
                     return Expression.Constant(ConversionCost.NoConversion); // if value can be converted, it would be handled above
                 }
 
+                // to System.Delegate
+                if (target.IsSubclassOf(typeof(Delegate)) && t == typeof(Closure))
+                {
+                    return Expression.Constant(ConversionCost.ImplicitCast);
+                }
+
                 if (ReflectionUtils.IsPhpClassType(target))
                 {
                     if (!t.IsInterface && !target.IsInterface && !target.IsAssignableFrom(t) && !t.IsAssignableFrom(target))

src/Peachpie.Runtime/PhpValue.cs

@@ -308,7 +308,12 @@ public object ToClass()
                     return Array.ToObject();
 
                 case PhpTypeCode.Object:
-                    return (Object is IPhpConvertible conv) ? conv.ToClass() : Object;
+                    return Object is IPhpConvertible conv
+                        ? conv.ToClass()
+                        //: Object is IStructBox structbox // CONSIDER: IStructBox is a regular PHP interface with conversions and methods, works well in PHP + it can have a IDynamicMetaObjectProvider
+                        //    ? structbox.BoxedValue  // box the value type
+                            : Object
+                        ;
 
                 case PhpTypeCode.Alias:
                     return Alias.Value.ToClass();

src/Peachpie.Runtime/PhpValueConverter.cs

@@ -3,6 +3,7 @@
 using System.Diagnostics;
 using System.Reflection;
 using System.Text;
+using System.Threading;
 
 namespace Pchp.Core
 {
@@ -70,6 +71,8 @@ static Delegate Create_PhpValue_to_T()
                             if (typeU == typeof(double)) return new Func<PhpValue, Nullable<double>>(x => Operators.IsSet(x) ? (double?)x.ToDouble() : null);
                         }
                     }
+
+                    if (typeof(T) == typeof(CancellationToken)) return new Func<PhpValue, CancellationToken>(x => Convert.UnwrapStruct<CancellationToken>(x));
                 }
                 else // type.IsReferenceType
                 {