2004-11-17 Atsushi Enomoto <atsushi@ximian.com>
[mono.git] / mcs / gmcs / generic.cs
index b6f6ca8df7cdb733ceede78dcc75529d50f9838d..0720906b141f82ce771ef12a67b85c39e3342eff 100644 (file)
@@ -15,72 +15,205 @@ using System.Text;
        
 namespace Mono.CSharp {
 
+       public abstract class GenericConstraints {
+               public abstract GenericParameterAttributes Attributes {
+                       get;
+               }
+
+               public bool HasConstructorConstraint {
+                       get { return (Attributes & GenericParameterAttributes.DefaultConstructorConstraint) != 0; }
+               }
+
+               public bool HasReferenceTypeConstraint {
+                       get { return (Attributes & GenericParameterAttributes.ReferenceTypeConstraint) != 0; }
+               }
+
+               public bool HasValueTypeConstraint {
+                       get { return (Attributes & GenericParameterAttributes.ValueTypeConstraint) != 0; }
+               }
+
+               public virtual bool HasClassConstraint {
+                       get { return ClassConstraint != null; }
+               }
+
+               public abstract Type ClassConstraint {
+                       get;
+               }
+
+               public abstract Type[] InterfaceConstraints {
+                       get;
+               }
+
+               public abstract Type EffectiveBaseClass {
+                       get;
+               }
+
+               // <summary>
+               //   Returns whether the type parameter is "known to be a reference type".
+               // </summary>
+               public virtual bool IsReferenceType {
+                       get {
+                               if (HasReferenceTypeConstraint)
+                                       return true;
+                               if (HasValueTypeConstraint)
+                                       return false;
+
+                               if (ClassConstraint != null) {
+                                       if (ClassConstraint.IsValueType)
+                                               return false;
+
+                                       if (ClassConstraint != TypeManager.object_type)
+                                               return true;
+                               }
+
+                               foreach (Type t in InterfaceConstraints) {
+                                       if (!t.IsGenericParameter)
+                                               continue;
+
+                                       GenericConstraints gc = TypeManager.GetTypeParameterConstraints (t);
+                                       if ((gc != null) && gc.IsReferenceType)
+                                               return true;
+                               }
+
+                               return false;
+                       }
+               }
+
+               // <summary>
+               //   Returns whether the type parameter is "known to be a value type".
+               // </summary>
+               public virtual bool IsValueType {
+                       get {
+                               if (HasValueTypeConstraint)
+                                       return true;
+                               if (HasReferenceTypeConstraint)
+                                       return false;
+
+                               if (ClassConstraint != null) {
+                                       if (!ClassConstraint.IsValueType)
+                                               return false;
+
+                                       if (ClassConstraint != TypeManager.value_type)
+                                               return true;
+                               }
+
+                               foreach (Type t in InterfaceConstraints) {
+                                       if (!t.IsGenericParameter)
+                                               continue;
+
+                                       GenericConstraints gc = TypeManager.GetTypeParameterConstraints (t);
+                                       if ((gc != null) && gc.IsValueType)
+                                               return true;
+                               }
+
+                               return false;
+                       }
+               }
+       }
+
+       public enum SpecialConstraint
+       {
+               Constructor,
+               ReferenceType,
+               ValueType
+       }
+
        //
        // Tracks the constraints for a type parameter
        //
-       public class Constraints {
-               string type_parameter;
+       public class Constraints : GenericConstraints {
+               string name;
                ArrayList constraints;
                Location loc;
                
                //
-               // type_parameter is the identifier, constraints is an arraylist of
+               // name is the identifier, constraints is an arraylist of
                // Expressions (with types) or `true' for the constructor constraint.
                // 
-               public Constraints (string type_parameter, ArrayList constraints,
+               public Constraints (string name, ArrayList constraints,
                                    Location loc)
                {
-                       this.type_parameter = type_parameter;
+                       this.name = name;
                        this.constraints = constraints;
                        this.loc = loc;
                }
 
                public string TypeParameter {
                        get {
-                               return type_parameter;
+                               return name;
                        }
                }
 
-               protected void Error (string message)
-               {
-                       Report.Error (-218, "Invalid constraints clause for type " +
-                                     "parameter `{0}': {1}", type_parameter, message);
-               }
-
-               bool has_ctor_constraint;
+               GenericParameterAttributes attrs;
                TypeExpr class_constraint;
                ArrayList iface_constraints;
-               TypeExpr[] constraint_types;
-               int num_constraints;
-
-               public bool HasConstructorConstraint {
-                       get { return has_ctor_constraint; }
-               }
+               ArrayList type_param_constraints;
+               int num_constraints, first_constraint;
+               Type class_constraint_type;
+               Type[] iface_constraint_types;
+               Type effective_base_type;
 
                public bool Resolve (DeclSpace ds)
                {
                        iface_constraints = new ArrayList ();
+                       type_param_constraints = new ArrayList ();
 
                        foreach (object obj in constraints) {
-                               if (has_ctor_constraint) {
-                                       Error ("can only use one constructor constraint and " +
-                                              "it must be the last constraint in the list.");
+                               if (HasConstructorConstraint) {
+                                       Report.Error (401, loc,
+                                                     "The new() constraint must be last.");
                                        return false;
                                }
 
-                               if (obj is bool) {
-                                       has_ctor_constraint = true;
+                               if (obj is SpecialConstraint) {
+                                       SpecialConstraint sc = (SpecialConstraint) obj;
+
+                                       if (sc == SpecialConstraint.Constructor) {
+                                               if (!HasValueTypeConstraint) {
+                                                       attrs |= GenericParameterAttributes.DefaultConstructorConstraint;
+                                                       continue;
+                                               }
+
+                                               Report.Error (
+                                                       451, loc, "The new () constraint " +
+                                                       "cannot be used with the `struct' " +
+                                                       "constraint.");
+                                               return false;
+                                       }
+
+                                       if ((num_constraints > 0) || HasReferenceTypeConstraint || HasValueTypeConstraint) {
+                                               Report.Error (449, loc,
+                                                             "The `class' or `struct' " +
+                                                             "constraint must be first");
+                                               return false;
+                                       }
+
+                                       if (sc == SpecialConstraint.ReferenceType)
+                                               attrs |= GenericParameterAttributes.ReferenceTypeConstraint;
+                                       else
+                                               attrs |= GenericParameterAttributes.ValueTypeConstraint;
                                        continue;
                                }
 
-                               TypeExpr expr = ds.ResolveTypeExpr ((Expression) obj, false, loc);
+                               TypeExpr expr = ds.ResolveTypeExpr ((Expression) obj, loc);
                                if (expr == null)
                                        return false;
 
-                               if (expr.IsInterface)
+                               TypeParameterExpr texpr = expr as TypeParameterExpr;
+                               if (texpr != null)
+                                       type_param_constraints.Add (expr);
+                               else if (expr.IsInterface)
                                        iface_constraints.Add (expr);
                                else if (class_constraint != null) {
-                                       Error ("can have at most one class constraint.");
+                                       Report.Error (406, loc,
+                                                     "`{0}': the class constraint for `{1}' " +
+                                                     "must come before any other constraints.",
+                                                     expr.Name, name);
+                                       return false;
+                               } else if (HasReferenceTypeConstraint || HasValueTypeConstraint) {
+                                       Report.Error (450, loc, "`{0}': cannot specify both " +
+                                                     "a constraint class and the `class' " +
+                                                     "or `struct' constraint.", expr.Name);
                                        return false;
                                } else
                                        class_constraint = expr;
@@ -88,57 +221,295 @@ namespace Mono.CSharp {
                                num_constraints++;
                        }
 
-                       constraint_types = new TypeExpr [num_constraints];
-                       int pos = 0;
-                       if (class_constraint != null)
-                               constraint_types [pos++] = class_constraint;
-                       iface_constraints.CopyTo (constraint_types, pos);
+                       return true;
+               }
+
+               bool CheckTypeParameterConstraints (TypeParameter tparam, Hashtable seen)
+               {
+                       seen.Add (tparam, true);
+
+                       Constraints constraints = tparam.Constraints;
+                       if (constraints == null)
+                               return true;
+
+                       if (constraints.HasValueTypeConstraint) {
+                               Report.Error (456, loc, "Type parameter `{0}' has " +
+                                             "the `struct' constraint, so it cannot " +
+                                             "be used as a constraint for `{1}'",
+                                             tparam.Name, name);
+                               return false;
+                       }
+
+                       if (constraints.type_param_constraints == null)
+                               return true;
+
+                       foreach (TypeParameterExpr expr in constraints.type_param_constraints) {
+                               if (seen.Contains (expr.TypeParameter)) {
+                                       Report.Error (454, loc, "Circular constraint " +
+                                                     "dependency involving `{0}' and `{1}'",
+                                                     tparam.Name, expr.Name);
+                                       return false;
+                               }
+
+                               if (!CheckTypeParameterConstraints (expr.TypeParameter, seen))
+                                       return false;
+                       }
 
                        return true;
                }
 
-               public Type[] ResolveTypes (EmitContext ec)
+               public bool ResolveTypes (EmitContext ec)
                {
-                       Type [] types = new Type [constraint_types.Length];
+                       foreach (TypeParameterExpr expr in type_param_constraints) {
+                               Hashtable seen = new Hashtable ();
+                               if (!CheckTypeParameterConstraints (expr.TypeParameter, seen))
+                                       return false;
+                       }
+
+                       ArrayList list = new ArrayList ();
+
+                       foreach (TypeExpr iface_constraint in iface_constraints) {
+                               Type resolved = iface_constraint.ResolveType (ec);
+                               if (resolved == null)
+                                       return false;
 
-                       for (int i = 0; i < constraint_types.Length; i++)
-                               types [i] = constraint_types [i].ResolveType (ec);
+                               foreach (Type type in list) {
+                                       if (!type.Equals (resolved))
+                                               continue;
 
-                       return types;
+                                       Report.Error (405, loc,
+                                                     "Duplicate constraint `{0}' for type " +
+                                                     "parameter `{1}'.", resolved, name);
+                                       return false;
+                               }
+
+                               list.Add (resolved);
+                       }
+
+                       foreach (TypeParameterExpr expr in type_param_constraints) {
+                               Type resolved = expr.ResolveType (ec);
+                               if (resolved == null)
+                                       return false;
+
+                               foreach (Type type in list) {
+                                       if (!type.Equals (resolved))
+                                               continue;
+
+                                       Report.Error (405, loc,
+                                                     "Duplicate constraint `{0}' for type " +
+                                                     "parameter `{1}'.", resolved, name);
+                                       return false;
+                               }
+
+                               list.Add (resolved);
+                       }
+
+                       iface_constraint_types = new Type [list.Count];
+                       list.CopyTo (iface_constraint_types, 0);
+
+                       if (class_constraint != null) {
+                               class_constraint_type = class_constraint.ResolveType (ec);
+                               if (class_constraint_type == null)
+                                       return false;
+
+                               if (class_constraint_type.IsSealed) {
+                                       Report.Error (701, loc,
+                                                     "`{0}' is not a valid bound.  Bounds " +
+                                                     "must be interfaces or non sealed " +
+                                                     "classes", class_constraint_type);
+                                       return false;
+                               }
+
+                               if ((class_constraint_type == TypeManager.array_type) ||
+                                   (class_constraint_type == TypeManager.delegate_type) ||
+                                   (class_constraint_type == TypeManager.enum_type) ||
+                                   (class_constraint_type == TypeManager.value_type) ||
+                                   (class_constraint_type == TypeManager.object_type)) {
+                                       Report.Error (702, loc,
+                                                     "Bound cannot be special class `{0}'",
+                                                     class_constraint_type);
+                                       return false;
+                               }
+                       }
+
+                       if (class_constraint_type != null)
+                               effective_base_type = class_constraint_type;
+                       else if (HasValueTypeConstraint)
+                               effective_base_type = TypeManager.value_type;
+                       else
+                               effective_base_type = TypeManager.object_type;
+
+                       return true;
+               }
+
+               public bool CheckDependencies (EmitContext ec)
+               {
+                       foreach (TypeParameterExpr expr in type_param_constraints) {
+                               if (!CheckDependencies (expr.TypeParameter, ec))
+                                       return false;
+                       }
+
+                       return true;
+               }
+
+               bool CheckDependencies (TypeParameter tparam, EmitContext ec)
+               {
+                       Constraints constraints = tparam.Constraints;
+                       if (constraints == null)
+                               return true;
+
+                       if (HasValueTypeConstraint && constraints.HasClassConstraint) {
+                               Report.Error (455, loc, "Type parameter `{0}' inherits " +
+                                             "conflicting constraints `{1}' and `{2}'",
+                                             name, constraints.ClassConstraint,
+                                             "System.ValueType");
+                               return false;
+                       }
+
+                       if (HasClassConstraint && constraints.HasClassConstraint) {
+                               Type t1 = ClassConstraint;
+                               TypeExpr e1 = class_constraint;
+                               Type t2 = constraints.ClassConstraint;
+                               TypeExpr e2 = constraints.class_constraint;
+
+                               if (!Convert.ImplicitReferenceConversionExists (ec, e1, t2) &&
+                                   !Convert.ImplicitReferenceConversionExists (ec, e2, t1)) {
+                                       Report.Error (455, loc,
+                                                     "Type parameter `{0}' inherits " +
+                                                     "conflicting constraints `{1}' and `{2}'",
+                                                     name, t1, t2);
+                                       return false;
+                               }
+                       }
+
+                       if (constraints.type_param_constraints == null)
+                               return true;
+
+                       foreach (TypeParameterExpr expr in constraints.type_param_constraints) {
+                               if (!CheckDependencies (expr.TypeParameter, ec))
+                                       return false;
+                       }
+
+                       return true;
+               }
+
+               public void Define (GenericTypeParameterBuilder type)
+               {
+                       type.SetGenericParameterAttributes (attrs);
+               }
+
+               public override GenericParameterAttributes Attributes {
+                       get { return attrs; }
+               }
+
+               public override bool HasClassConstraint {
+                       get { return class_constraint != null; }
+               }
+
+               public override Type ClassConstraint {
+                       get { return class_constraint_type; }
+               }
+
+               public override Type[] InterfaceConstraints {
+                       get { return iface_constraint_types; }
+               }
+
+               public override Type EffectiveBaseClass {
+                       get { return effective_base_type; }
+               }
+
+               internal bool IsSubclassOf (Type t)
+               {
+                       if ((class_constraint_type != null) &&
+                           class_constraint_type.IsSubclassOf (t))
+                               return true;
+
+                       if (iface_constraint_types == null)
+                               return false;
+
+                       foreach (Type iface in iface_constraint_types) {
+                               if (TypeManager.IsSubclassOf (iface, t))
+                                       return true;
+                       }
+
+                       return false;
+               }
+
+               public bool CheckInterfaceMethod (EmitContext ec, GenericConstraints gc)
+               {
+                       if (!ResolveTypes (ec))
+                               return false;
+
+                       if (gc.Attributes != attrs)
+                               return false;
+
+                       if (HasClassConstraint != gc.HasClassConstraint)
+                               return false;
+                       if (HasClassConstraint && !TypeManager.IsEqual (gc.ClassConstraint, ClassConstraint))
+                               return false;
+
+                       int gc_icount = gc.InterfaceConstraints != null ?
+                               gc.InterfaceConstraints.Length : 0;
+                       int icount = InterfaceConstraints != null ?
+                               InterfaceConstraints.Length : 0;
+
+                       if (gc_icount != icount)
+                               return false;
+
+                       foreach (Type iface in gc.InterfaceConstraints) {
+                               bool ok = false;
+                               foreach (Type check in InterfaceConstraints) {
+                                       if (TypeManager.IsEqual (iface, check)) {
+                                               ok = true;
+                                               break;
+                                       }
+                               }
+
+                               if (!ok)
+                                       return false;
+                       }
+
+                       return true;
                }
        }
 
        //
        // This type represents a generic type parameter
        //
-       public class TypeParameter {
+       public class TypeParameter : MemberCore, IMemberContainer {
                string name;
+               GenericConstraints gc;
                Constraints constraints;
                Location loc;
-               Type type;
+               GenericTypeParameterBuilder type;
 
-               public TypeParameter (string name, Constraints constraints, Location loc)
+               public TypeParameter (TypeContainer parent, string name,
+                                     Constraints constraints, Location loc)
+                       : base (parent, new MemberName (name), null, loc)
                {
                        this.name = name;
                        this.constraints = constraints;
                        this.loc = loc;
                }
 
-               public string Name {
+               public GenericConstraints GenericConstraints {
                        get {
-                               return name;
+                               return gc != null ? gc : constraints;
                        }
                }
 
-               public Location Location {
+               public Constraints Constraints {
                        get {
-                               return loc;
+                               return constraints;
                        }
                }
 
-               public Constraints Constraints {
+               public bool HasConstructorConstraint {
                        get {
-                               return constraints;
+                               if (constraints != null)
+                                       return constraints.HasConstructorConstraint;
+
+                               return false;
                        }
                }
 
@@ -156,40 +527,277 @@ namespace Mono.CSharp {
                        return true;
                }
 
-               public Type Define (TypeBuilder tb)
+               public void Define (GenericTypeParameterBuilder type)
                {
-                       type = tb.DefineGenericParameter (name);
-                       return type;
+                       if (this.type != null)
+                               throw new InvalidOperationException ();
+
+                       this.type = type;
+                       TypeManager.AddTypeParameter (type, this);
                }
 
-               public Type DefineMethod (MethodBuilder mb)
+               public void DefineConstraints ()
                {
-                       type = mb.DefineGenericParameter (name);
-                       return type;
+                       if (constraints != null)
+                               constraints.Define (type);
                }
 
-               public void DefineType (EmitContext ec, TypeBuilder tb)
+               public bool DefineType (EmitContext ec)
                {
-                       int index = type.GenericParameterPosition;
-                       if (constraints == null)
-                               tb.SetGenericParameterConstraints (index, new Type [0]);
-                       else
-                               tb.SetGenericParameterConstraints (index, constraints.ResolveTypes (ec));
+                       return DefineType (ec, null, null, false);
                }
 
-               public void DefineType (EmitContext ec, MethodBuilder mb)
+               public bool DefineType (EmitContext ec, MethodBuilder builder,
+                                       MethodInfo implementing, bool is_override)
+               {
+                       if (implementing != null) {
+                               if (is_override && (constraints != null)) {
+                                       Report.Error (
+                                               460, loc, "Constraints for override and " +
+                                               "explicit interface implementation methods " +
+                                               "are inherited from the base method so they " +
+                                               "cannot be specified directly");
+                                       return false;
+                               }
+
+                               MethodBase mb = implementing;
+                               if (mb.Mono_IsInflatedMethod)
+                                       mb = mb.GetGenericMethodDefinition ();
+
+                               int pos = type.GenericParameterPosition;
+                               ParameterData pd = Invocation.GetParameterData (mb);
+                               GenericConstraints temp_gc = pd.GenericConstraints (pos);
+                               Type mparam = mb.GetGenericArguments () [pos];
+
+                               if (temp_gc != null)
+                                       gc = new InflatedConstraints (temp_gc, implementing.DeclaringType);
+                               else if (constraints != null)
+                                       gc = new InflatedConstraints (constraints, implementing.DeclaringType);
+
+                               bool ok = true;
+                               if (constraints != null) {
+                                       if (temp_gc == null)
+                                               ok = false;
+                                       else if (!constraints.CheckInterfaceMethod (ec, gc))
+                                               ok = false;
+                               } else {
+                                       if (!is_override && (temp_gc != null))
+                                               ok = false;
+                               }
+
+                               if (!ok) {
+                                       Report.SymbolRelatedToPreviousError (implementing);
+
+                                       Report.Error (
+                                               425, loc, "The constraints for type " +
+                                               "parameter `{0}' of method `{1}' must match " +
+                                               "the constraints for type parameter `{2}' " +
+                                               "of interface method `{3}'.  Consider using " +
+                                               "an explicit interface implementation instead",
+                                               Name, TypeManager.CSharpSignature (builder),
+                                               mparam, TypeManager.CSharpSignature (mb));
+                                       return false;
+                               }
+                       } else {
+                               if (constraints != null) {
+                                       if (!constraints.ResolveTypes (ec))
+                                               return false;
+                               }
+
+                               gc = (GenericConstraints) constraints;
+                       }
+
+                       if (gc == null)
+                               return true;
+
+                       if (gc.HasClassConstraint)
+                               type.SetBaseTypeConstraint (gc.ClassConstraint);
+
+                       type.SetInterfaceConstraints (gc.InterfaceConstraints);
+                       TypeManager.RegisterBuilder (type, gc.InterfaceConstraints);
+
+                       return true;
+               }
+
+               public bool CheckDependencies (EmitContext ec)
+               {
+                       if (constraints != null)
+                               return constraints.CheckDependencies (ec);
+
+                       return true;
+               }
+
+               //
+               // MemberContainer
+               //
+
+               public override bool Define ()
+               {
+                       return true;
+               }
+
+               protected override void VerifyObsoleteAttribute ()
+               { }
+
+               public override void ApplyAttributeBuilder (Attribute a,
+                                                           CustomAttributeBuilder cb)
+               { }
+
+               public override AttributeTargets AttributeTargets {
+                       get {
+                               return (AttributeTargets) 0;
+                       }
+               }
+
+               public override string[] ValidAttributeTargets {
+                       get {
+                               return new string [0];
+                       }
+               }
+
+               //
+               // IMemberContainer
+               //
+
+               string IMemberContainer.Name {
+                       get { return Name; }
+               }
+
+               MemberCache IMemberContainer.ParentCache {
+                       get { return null; }
+               }
+
+               bool IMemberContainer.IsInterface {
+                       get { return true; }
+               }
+
+               MemberList IMemberContainer.GetMembers (MemberTypes mt, BindingFlags bf)
+               {
+                       return FindMembers (mt, bf, null, null);
+               }
+
+               MemberCache IMemberContainer.MemberCache {
+                       get { return null; }
+               }
+
+               public MemberList FindMembers (MemberTypes mt, BindingFlags bf,
+                                              MemberFilter filter, object criteria)
                {
-                       int index = type.GenericParameterPosition;
                        if (constraints == null)
-                               mb.SetGenericParameterConstraints (index, new Type [0]);
-                       else
-                               mb.SetGenericParameterConstraints (index, constraints.ResolveTypes (ec));
+                               return MemberList.Empty;
+
+                       ArrayList members = new ArrayList ();
+
+                       GenericConstraints gc = (GenericConstraints) constraints;
+
+                       if (gc.HasClassConstraint) {
+                               MemberList list = TypeManager.FindMembers (
+                                       gc.ClassConstraint, mt, bf, filter, criteria);
+
+                               members.AddRange (list);
+                       }
+
+                       foreach (Type t in gc.InterfaceConstraints) {
+                               MemberList list = TypeManager.FindMembers (
+                                       t, mt, bf, filter, criteria);
+
+                               members.AddRange (list);
+                       }
+
+                       return new MemberList (members);
+               }
+
+               public bool IsSubclassOf (Type t)
+               {
+                       if (type.Equals (t))
+                               return true;
+
+                       if (constraints != null)
+                               return constraints.IsSubclassOf (t);
+
+                       return false;
                }
 
                public override string ToString ()
                {
                        return "TypeParameter[" + name + "]";
                }
+
+               protected class InflatedConstraints : GenericConstraints
+               {
+                       GenericConstraints gc;
+                       Type base_type;
+                       Type class_constraint;
+                       Type[] iface_constraints;
+                       Type[] dargs;
+                       Type declaring;
+
+                       public InflatedConstraints (GenericConstraints gc, Type declaring)
+                       {
+                               this.gc = gc;
+                               this.declaring = declaring;
+
+                               dargs = TypeManager.GetTypeArguments (declaring);
+
+                               ArrayList list = new ArrayList ();
+                               if (gc.HasClassConstraint)
+                                       list.Add (inflate (gc.ClassConstraint));
+                               foreach (Type iface in gc.InterfaceConstraints)
+                                       list.Add (inflate (iface));
+
+                               bool has_class_constr = false;
+                               if (list.Count > 0) {
+                                       Type first = (Type) list [0];
+                                       has_class_constr = !first.IsInterface && !first.IsGenericParameter;
+                               }
+
+                               if ((list.Count > 0) && has_class_constr) {
+                                       class_constraint = (Type) list [0];
+                                       iface_constraints = new Type [list.Count - 1];
+                                       list.CopyTo (1, iface_constraints, 0, list.Count - 1);
+                               } else {
+                                       iface_constraints = new Type [list.Count];
+                                       list.CopyTo (iface_constraints, 0);
+                               }
+
+                               if (HasValueTypeConstraint)
+                                       base_type = TypeManager.value_type;
+                               else if (class_constraint != null)
+                                       base_type = class_constraint;
+                               else
+                                       base_type = TypeManager.object_type;
+                       }
+
+                       Type inflate (Type t)
+                       {
+                               if (t == null)
+                                       return null;
+                               if (t.IsGenericParameter)
+                                       return dargs [t.GenericParameterPosition];
+                               if (t.IsGenericInstance) {
+                                       t = t.GetGenericTypeDefinition ();
+                                       t = t.BindGenericParameters (dargs);
+                               }
+
+                               return t;
+                       }
+
+                       public override GenericParameterAttributes Attributes {
+                               get { return gc.Attributes; }
+                       }
+
+                       public override Type ClassConstraint {
+                               get { return class_constraint; }
+                       }
+
+                       public override Type EffectiveBaseClass {
+                               get { return base_type; }
+                       }
+
+                       public override Type[] InterfaceConstraints {
+                               get { return iface_constraints; }
+                       }
+               }
        }
 
        //
@@ -225,6 +833,15 @@ namespace Mono.CSharp {
                        return this;
                }
 
+               public override bool IsInterface {
+                       get { return false; }
+               }
+
+               public override bool CheckAccessLevel (DeclSpace ds)
+               {
+                       return true;
+               }
+
                public void Error_CannotUseAsUnmanagedType (Location loc)
                {
                        Report.Error (-203, loc, "Can not use type parameter as unamanged type");
@@ -235,6 +852,7 @@ namespace Mono.CSharp {
                public readonly Location Location;
                ArrayList args;
                Type[] atypes;
+               int dimension;
                bool has_type_args;
                bool created;
                
@@ -244,6 +862,12 @@ namespace Mono.CSharp {
                        this.Location = loc;
                }
 
+               public TypeArguments (int dimension, Location loc)
+               {
+                       this.dimension = dimension;
+                       this.Location = loc;
+               }
+
                public void Add (Expression type)
                {
                        if (created)
@@ -291,7 +915,16 @@ namespace Mono.CSharp {
 
                public int Count {
                        get {
-                               return args.Count;
+                               if (dimension > 0)
+                                       return dimension;
+                               else
+                                       return args.Count;
+                       }
+               }
+
+               public bool IsUnbound {
+                       get {
+                               return dimension > 0;
                        }
                }
 
@@ -299,12 +932,13 @@ namespace Mono.CSharp {
                {
                        StringBuilder s = new StringBuilder ();
 
-                       int count = args.Count;
+                       int count = Count;
                        for (int i = 0; i < count; i++){
                                //
                                // FIXME: Use TypeManager.CSharpname once we have the type
                                //
-                               s.Append (args [i].ToString ());
+                               if (args != null)
+                                       s.Append (args [i].ToString ());
                                if (i+1 < count)
                                        s.Append (",");
                        }
@@ -318,10 +952,9 @@ namespace Mono.CSharp {
                        bool ok = true;
 
                        atypes = new Type [count];
-                       
+
                        for (int i = 0; i < count; i++){
-                               TypeExpr te = ds.ResolveTypeExpr (
-                                       (Expression) args [i], false, Location);
+                               TypeExpr te = ((Expression) args [i]).ResolveAsTypeTerminal (ec);
                                if (te == null) {
                                        ok = false;
                                        continue;
@@ -349,7 +982,7 @@ namespace Mono.CSharp {
                public ConstructedType (string name, TypeArguments args, Location l)
                {
                        loc = l;
-                       this.name = name;
+                       this.name = MemberName.MakeName (name, args.Count);
                        this.args = args;
 
                        eclass = ExprClass.Type;
@@ -406,35 +1039,135 @@ namespace Mono.CSharp {
                        get { return args; }
                }
 
-               protected bool CheckConstraints (int index)
+               protected string DeclarationName {
+                       get {
+                               StringBuilder sb = new StringBuilder ();
+                               sb.Append (gt.FullName);
+                               sb.Append ("<");
+                               for (int i = 0; i < gen_params.Length; i++) {
+                                       if (i > 0)
+                                               sb.Append (",");
+                                       sb.Append (gen_params [i]);
+                               }
+                               sb.Append (">");
+                               return sb.ToString ();
+                       }
+               }
+
+               protected bool CheckConstraint (EmitContext ec, Type ptype, Expression expr,
+                                               Type ctype)
+               {
+                       if (TypeManager.HasGenericArguments (ctype)) {
+                               Type[] types = TypeManager.GetTypeArguments (ctype);
+
+                               TypeArguments new_args = new TypeArguments (loc);
+
+                               for (int i = 0; i < types.Length; i++) {
+                                       Type t = types [i];
+
+                                       if (t.IsGenericParameter) {
+                                               int pos = t.GenericParameterPosition;
+                                               t = args.Arguments [pos];
+                                       }
+                                       new_args.Add (new TypeExpression (t, loc));
+                               }
+
+                               ctype = new ConstructedType (ctype, new_args, loc).ResolveType (ec);
+                               if (ctype == null)
+                                       return false;
+                       }
+
+                       return Convert.ImplicitStandardConversionExists (ec, expr, ctype);
+               }
+
+               protected bool CheckConstraints (EmitContext ec, int index)
                {
                        Type atype = atypes [index];
                        Type ptype = gen_params [index];
 
-                       //// FIXME
-                       return true;
+                       if (atype == ptype)
+                               return true;
+
+                       Expression aexpr = new EmptyExpression (atype);
+
+                       GenericConstraints gc = TypeManager.GetTypeParameterConstraints (ptype);
+                       if (gc == null)
+                               return true;
 
                        //
-                       // First, check parent class.
+                       // First, check the `class' and `struct' constraints.
                        //
-                       if ((ptype.BaseType != atype.BaseType) &&
-                           !atype.BaseType.IsSubclassOf (ptype.BaseType)) {
-                               Report.Error (-219, loc, "Cannot create constructed type `{0}': " +
-                                             "type argument `{1}' must derive from `{2}'.",
-                                             full_name, atype, ptype.BaseType);
+                       if (gc.HasReferenceTypeConstraint && !atype.IsClass) {
+                               Report.Error (452, loc, "The type `{0}' must be " +
+                                             "a reference type in order to use it " +
+                                             "as type parameter `{1}' in the " +
+                                             "generic type or method `{2}'.",
+                                             atype, ptype, DeclarationName);
+                               return false;
+                       } else if (gc.HasValueTypeConstraint && !atype.IsValueType) {
+                               Report.Error (453, loc, "The type `{0}' must be " +
+                                             "a value type in order to use it " +
+                                             "as type parameter `{1}' in the " +
+                                             "generic type or method `{2}'.",
+                                             atype, ptype, DeclarationName);
                                return false;
                        }
 
                        //
-                       // Now, check the interfaces.
+                       // The class constraint comes next.
+                       //
+                       if (gc.HasClassConstraint) {
+                               if (!CheckConstraint (ec, ptype, aexpr, gc.ClassConstraint)) {
+                                       Report.Error (309, loc, "The type `{0}' must be " +
+                                                     "convertible to `{1}' in order to " +
+                                                     "use it as parameter `{2}' in the " +
+                                                     "generic type or method `{3}'",
+                                                     atype, gc.ClassConstraint, ptype, DeclarationName);
+                                       return false;
+                               }
+                       }
+
+                       //
+                       // Now, check the interface constraints.
+                       //
+                       foreach (Type it in gc.InterfaceConstraints) {
+                               Type itype;
+                               if (it.IsGenericParameter)
+                                       itype = atypes [it.GenericParameterPosition];
+                               else
+                                       itype = it;
+
+                               if (!CheckConstraint (ec, ptype, aexpr, itype)) {
+                                       Report.Error (309, loc, "The type `{0}' must be " +
+                                                     "convertible to `{1}' in order to " +
+                                                     "use it as parameter `{2}' in the " +
+                                                     "generic type or method `{3}'",
+                                                     atype, itype, ptype, DeclarationName);
+                                       return false;
+                               }
+                       }
+
+                       //
+                       // Finally, check the constructor constraint.
                        //
-                       foreach (Type itype in ptype.GetInterfaces ()) {
-                               if (TypeManager.ImplementsInterface (atype, itype))
-                                       continue;
 
-                               Report.Error (-219, loc, "Cannot create constructed type `{0}: " +
-                                             "type argument `{1}' must implement interface `{2}'.",
-                                             full_name, atype, itype);
+                       if (!gc.HasConstructorConstraint)
+                               return true;
+
+                       if (TypeManager.IsBuiltinType (atype))
+                               return true;
+
+                       MethodGroupExpr mg = Expression.MemberLookup (
+                               ec, atype, ".ctor", MemberTypes.Constructor,
+                               BindingFlags.Public | BindingFlags.Instance |
+                               BindingFlags.DeclaredOnly, loc)
+                               as MethodGroupExpr;
+
+                       if (atype.IsAbstract || (mg == null) || !mg.IsInstance) {
+                               Report.Error (310, loc, "The type `{0}' must have a public " +
+                                             "parameterless constructor in order to use it " +
+                                             "as parameter `{1}' in the generic type or " +
+                                             "method `{2}'", atype, ptype, DeclarationName);
                                return false;
                        }
 
@@ -443,8 +1176,10 @@ namespace Mono.CSharp {
 
                public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
                {
-                       if (gt != null)
+                       if (type != null)
                                return this;
+                       if (gt != null)
+                               return DoResolveType (ec);
 
                        //
                        // First, resolve the generic type.
@@ -455,60 +1190,46 @@ namespace Mono.CSharp {
                                gt = nested.GetGenericTypeDefinition ();
 
                                TypeArguments new_args = new TypeArguments (loc);
-                               foreach (TypeParameter param in ds.TypeParameters)
-                                       new_args.Add (new TypeParameterExpr (param, loc));
+                               if (ds.IsGeneric) {
+                                       foreach (TypeParameter param in ds.TypeParameters)
+                                               new_args.Add (new TypeParameterExpr (param, loc));
+                               }
                                new_args.Add (args);
 
                                args = new_args;
-                               return this;
+                               return DoResolveType (ec);
                        }
 
-                       SimpleName sn = new SimpleName (name, args.Count, loc);
-                       TypeExpr resolved = sn.ResolveAsTypeTerminal (ec);
-                       if (resolved == null) {
-                               sn = new SimpleName (name, -1, loc);
-                               resolved = sn.ResolveAsTypeTerminal (ec);
-                               if ((resolved == null) || (resolved.Type == null)) {
-                                       Report.Error (246, loc,
-                                                     "The type or namespace name `{0}<...>' "+
-                                                     "could not be found", name);
-                                       return null;
-                               }
-
-                               Type t = resolved.Type;
-                               int num_args = TypeManager.GetNumberOfTypeArguments (t);
+                       Type t;
+                       int num_args;
 
-                               if (num_args == 0) {
-                                       Report.Error (308, loc,
-                                                     "The non-generic type `{0}' cannot " +
-                                                     "be used with type arguments.",
-                                                     TypeManager.CSharpName (t));
-                                       return null;
-                               }
+                       SimpleName sn = new SimpleName (name, loc);
+                       TypeExpr resolved = sn.ResolveAsTypeTerminal (ec);
+                       if (resolved == null)
+                               return null;
 
-                               Report.Error (305, loc,
-                                             "Using the generic type `{0}' " +
-                                             "requires {1} type arguments",
-                                             TypeManager.GetFullName (t), num_args);
+                       t = resolved.Type;
+                       if (t == null) {
+                               Report.Error (246, loc, "Cannot find type `{0}'<...>",
+                                             Basename);
                                return null;
                        }
 
-                       if (resolved.Type == null)
-                               throw new InternalErrorException (
-                                       "Failed to resolve constructed type `{0}'",
-                                       full_name);
+                       num_args = TypeManager.GetNumberOfTypeArguments (t);
+                       if (num_args == 0) {
+                               Report.Error (308, loc,
+                                             "The non-generic type `{0}' cannot " +
+                                             "be used with type arguments.",
+                                             TypeManager.CSharpName (t));
+                               return null;
+                       }
 
-                       gt = resolved.Type.GetGenericTypeDefinition ();
-                       return this;
+                       gt = t.GetGenericTypeDefinition ();
+                       return DoResolveType (ec);
                }
 
-               public override Type ResolveType (EmitContext ec)
+               TypeExpr DoResolveType (EmitContext ec)
                {
-                       if (type != null)
-                               return type;
-                       if (DoResolveAsTypeStep (ec) == null)
-                               return null;
-
                        //
                        // Resolve the arguments.
                        //
@@ -519,14 +1240,16 @@ namespace Mono.CSharp {
                        atypes = args.Arguments;
 
                        if (atypes.Length != gen_params.Length) {
-                               Report.Error (-217, loc, "Generic type `{0}' takes {1} " +
-                                             "type parameters, but specified {2}.", gt.Name,
-                                             gen_params.Length, atypes.Length);
+                               Report.Error (305, loc,
+                                             "Using the generic type `{0}' " +
+                                             "requires {1} type arguments",
+                                             TypeManager.GetFullName (gt),
+                                             gen_params.Length);
                                return null;
                        }
 
                        for (int i = 0; i < gen_params.Length; i++) {
-                               if (!CheckConstraints (i))
+                               if (!CheckConstraints (ec, i))
                                        return null;
                        }
 
@@ -534,18 +1257,12 @@ namespace Mono.CSharp {
                        // Now bind the parameters.
                        //
                        type = gt.BindGenericParameters (atypes);
-                       return type;
+                       return this;
                }
 
-               public Expression GetMemberAccess (EmitContext ec)
+               public Expression GetSimpleName (EmitContext ec)
                {
-                       TypeExpr current;
-                       if (ec.TypeContainer.CurrentType != null)
-                               current = ec.TypeContainer.CurrentType;
-                       else
-                               current = new TypeExpression (ec.ContainerType, loc);
-
-                       return new GenericMemberAccess (current, name, args, loc);
+                       return new SimpleName (Basename, args, loc);
                }
 
                public override bool CheckAccessLevel (DeclSpace ds)
@@ -578,12 +1295,6 @@ namespace Mono.CSharp {
                        get { return false; }
                }
 
-               public override TypeExpr[] GetInterfaces ()
-               {
-                       TypeExpr[] ifaces = TypeManager.GetInterfaces (gt);
-                       return ifaces;
-               }
-
                public override bool Equals (object obj)
                {
                        ConstructedType cobj = obj as ConstructedType;
@@ -596,6 +1307,16 @@ namespace Mono.CSharp {
                        return type == cobj.type;
                }
 
+               public string Basename {
+                       get {
+                               int pos = name.LastIndexOf ('`');
+                               if (pos >= 0)
+                                       return name.Substring (0, pos);
+                               else
+                                       return name;
+                       }
+               }
+
                public override string Name {
                        get {
                                return full_name;
@@ -605,9 +1326,9 @@ namespace Mono.CSharp {
 
        public class GenericMethod : DeclSpace
        {
-               public GenericMethod (NamespaceEntry ns, TypeContainer parent, string name,
-                                     Attributes attrs, Location l)
-                       : base (ns, parent, name, attrs, l)
+               public GenericMethod (NamespaceEntry ns, TypeContainer parent,
+                                     MemberName name, Location l)
+                       : base (ns, parent, name, null, l)
                { }
 
                public override TypeBuilder DefineType ()
@@ -615,31 +1336,39 @@ namespace Mono.CSharp {
                        throw new Exception ();
                }
 
-               public override bool Define (TypeContainer parent)
+               public override bool Define ()
                {
                        for (int i = 0; i < TypeParameters.Length; i++)
-                               if (!TypeParameters [i].Resolve (parent))
+                               if (!TypeParameters [i].Resolve (Parent))
                                        return false;
 
                        return true;
                }
 
-               public bool Define (TypeContainer parent, MethodBuilder mb)
+               public bool Define (MethodBuilder mb, Type return_type)
                {
-                       if (!Define (parent))
+                       if (!Define ())
                                return false;
 
-                       Type[] gen_params = new Type [TypeParameters.Length];
+                       GenericTypeParameterBuilder[] gen_params;
+                       string[] names = MemberName.TypeArguments.GetDeclarations ();
+                       gen_params = mb.DefineGenericParameters (names);
                        for (int i = 0; i < TypeParameters.Length; i++)
-                               gen_params [i] = TypeParameters [i].DefineMethod (mb);
+                               TypeParameters [i].Define (gen_params [i]);
+
+                       ec = new EmitContext (
+                               this, this, Location, null, return_type, ModFlags, false);
 
                        return true;
                }
 
-               public bool DefineType (EmitContext ec, MethodBuilder mb)
+               public bool DefineType (EmitContext ec, MethodBuilder mb,
+                                       MethodInfo implementing, bool is_override)
                {
                        for (int i = 0; i < TypeParameters.Length; i++)
-                               TypeParameters [i].DefineType (ec, mb);
+                               if (!TypeParameters [i].DefineType (
+                                           ec, mb, implementing, is_override))
+                                       return false;
 
                        return true;
                }
@@ -660,108 +1389,21 @@ namespace Mono.CSharp {
                                throw new Exception ();
                        }
                }
-       }
-
-       public class GenericMemberAccess : MemberAccess
-       {
-               TypeArguments args;
 
-               public GenericMemberAccess (Expression expr, string id, TypeArguments args, Location loc)
-                       : base (expr, id, args.Count, loc)
+               public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
-                       this.args = args;
+                       // FIXME
                }
 
-               private bool DoResolveBase (EmitContext ec)
+               protected override void VerifyObsoleteAttribute()
                {
-                       ConstructedType cexpr = expr as ConstructedType;
-                       if (cexpr != null) {
-                               TypeArguments new_args = new TypeArguments (loc);
-                               new_args.Add (cexpr.TypeArguments);
-                               new_args.Add (args);
-
-                               args = new_args;
-                       }
-
-                       return true;
+                       // FIXME
                }
 
-               public override Expression DoResolve (EmitContext ec, Expression right_side,
-                                                     ResolveFlags flags)
-               {
-                       if (!DoResolveBase (ec))
-                               return null;
-
-                       Expression expr = base.DoResolve (ec, right_side, flags);
-                       if (expr == null)
-                               return null;
-
-                       TypeExpr texpr = expr as TypeExpr;
-                       if (texpr != null) {
-                               Type t = texpr.ResolveType (ec);
-                               if (t == null)
-                                       return null;
-
-                               ConstructedType ctype = new ConstructedType (t, args, loc);
-                               return ctype.DoResolve (ec);
-                       }
-
-                       MethodGroupExpr mg = expr as MethodGroupExpr;
-                       if (mg == null) {
-                               return expr;
-                               Report.Error (-220, loc, "Member `{0}' has type arguments, but did " +
-                                             "not resolve as a method group.", Identifier);
-                               return null;
-                       }
-
-                       if (args.Resolve (ec) == false)
-                               return null;
-
-                       Type[] atypes = args.Arguments;
-
-                       ArrayList list = new ArrayList ();
-
-                       foreach (MethodBase method in mg.Methods) {
-                               MethodInfo mi = method as MethodInfo;
-                               if (mi == null)
-                                       continue;
-
-                               Type[] gen_params = mi.GetGenericArguments ();
-                       
-                               if (atypes.Length != gen_params.Length) {
-                                       Report.Error (-217, loc, "Generic method `{0}' takes {1} " +
-                                                     "type parameters, but specified {2}.", mi.Name,
-                                                     gen_params.Length, atypes.Length);
-                                       continue;
-                               }
-
-                               list.Add (mi.BindGenericParameters (args.Arguments));
+               public override AttributeTargets AttributeTargets {
+                       get {
+                               return AttributeTargets.Method | AttributeTargets.ReturnValue;
                        }
-
-                       MethodInfo[] methods = new MethodInfo [list.Count];
-                       list.CopyTo (methods, 0);
-
-                       MethodGroupExpr new_mg = new MethodGroupExpr (methods, mg.Location);
-                       new_mg.InstanceExpression = mg.InstanceExpression;
-                       new_mg.HasTypeArguments = true;
-                       return new_mg;
-               }
-
-               public override Expression ResolveAsTypeStep (EmitContext ec)
-               {
-                       if (!DoResolveBase (ec))
-                               return null;
-
-                       expr = base.ResolveAsTypeStep (ec);
-                       if (expr == null)
-                               return null;
-
-                       Type t = ((TypeExpr) expr).ResolveType (ec);
-                       if (t == null)
-                               return null;
-
-                       ConstructedType ctype = new ConstructedType (t, args, loc);
-                       return ctype.ResolveAsTypeStep (ec);
                }
        }
 
@@ -778,7 +1420,11 @@ namespace Mono.CSharp {
 
                public override Expression DoResolve (EmitContext ec)
                {
-                       type = ec.DeclSpace.ResolveType (expr, false, loc);
+                       TypeExpr texpr = expr.ResolveAsTypeTerminal (ec);
+                       if (texpr == null)
+                               return null;
+
+                       type = texpr.ResolveType (ec);
                        if (type == null)
                                return null;