vhdl: add support for default in interface subprogram. Fix #2163

12 files changed, 649 insertions, 419 deletions

diff --git a/src/vhdl/translate/trans-chap5.adb b/src/vhdl/translate/trans-chap5.adb
index e9b11f8eb..8ee426293 100644
--- a/src/vhdl/translate/trans-chap5.adb
+++ b/src/vhdl/translate/trans-chap5.adb
@@ -850,6 +850,9 @@ package body Trans.Chap5 is
                      Set_Map_Env (Formal_Env);
                      Chap2.Elab_Package_Instantiation_Declaration (Formal);
                      Set_Map_Env (Actual_Env);
+                  when Iir_Kinds_Interface_Subprogram_Declaration =>
+                     --  Expanded.
+                     null;
                   when others =>
                      Error_Kind ("elab_generic_map_aspect(open)", Formal);
                end case;
diff --git a/src/vhdl/vhdl-nodes.adb b/src/vhdl/vhdl-nodes.adb
index 71914dfd3..9b6329c74 100644
--- a/src/vhdl/vhdl-nodes.adb
+++ b/src/vhdl/vhdl-nodes.adb
@@ -2197,6 +2197,22 @@ package body Vhdl.Nodes is
       Set_Field3 (Target, Actual);
    end Set_Actual;
 
+   function Get_Open_Actual (Target : Iir) return Iir is
+   begin
+      pragma Assert (Target /= Null_Iir);
+      pragma Assert (Has_Open_Actual (Get_Kind (Target)),
+                     "no field Open_Actual");
+      return Get_Field3 (Target);
+   end Get_Open_Actual;
+
+   procedure Set_Open_Actual (Target : Iir; Actual : Iir) is
+   begin
+      pragma Assert (Target /= Null_Iir);
+      pragma Assert (Has_Open_Actual (Get_Kind (Target)),
+                     "no field Open_Actual");
+      Set_Field3 (Target, Actual);
+   end Set_Open_Actual;
+
    function Get_Actual_Conversion (Target : Iir) return Iir is
    begin
       pragma Assert (Target /= Null_Iir);
@@ -3132,6 +3148,22 @@ package body Vhdl.Nodes is
       Set_Field5 (Target, Chain);
    end Set_Interface_Declaration_Chain;
 
+   function Get_Default_Subprogram (Inter : Iir) return Iir is
+   begin
+      pragma Assert (Inter /= Null_Iir);
+      pragma Assert (Has_Default_Subprogram (Get_Kind (Inter)),
+                     "no field Default_Subprogram");
+      return Get_Field9 (Inter);
+   end Get_Default_Subprogram;
+
+   procedure Set_Default_Subprogram (Inter : Iir; Subprg : Iir) is
+   begin
+      pragma Assert (Inter /= Null_Iir);
+      pragma Assert (Has_Default_Subprogram (Get_Kind (Inter)),
+                     "no field Default_Subprogram");
+      Set_Field9 (Inter, Subprg);
+   end Set_Default_Subprogram;
+
    function Get_Subprogram_Specification (Target : Iir) return Iir is
    begin
       pragma Assert (Target /= Null_Iir);
diff --git a/src/vhdl/vhdl-nodes.ads b/src/vhdl/vhdl-nodes.ads
index 0fc291be2..376c99daa 100644
--- a/src/vhdl/vhdl-nodes.ads
+++ b/src/vhdl/vhdl-nodes.ads
@@ -449,6 +449,10 @@ package Vhdl.Nodes is
    -- Only for Iir_Kind_Association_Element_Terminal:
    --   Get/Set_Actual (Field3)
    --
+   --  For '<>' default interface subprogram.
+   -- Only for Iir_Kind_Association_Element_Open:
+   --   Get/Set_Open_Actual (Field3)
+   --
    -- Only for Iir_Kind_Association_Element_By_Individual:
    --   Get/Set_Individual_Association_Chain (Field4)
    --
@@ -1772,6 +1776,8 @@ package Vhdl.Nodes is
    --
    --   Get/Set_Return_Type_Mark (Field8)
    --
+   --   Get/Set_Default_Subprogram (Field9)
+   --
    --   Get/Set_Subprogram_Depth (Field10)
    --
    --   Get/Set_Seen_Flag (Flag1)
@@ -7909,6 +7915,10 @@ package Vhdl.Nodes is
    function Get_Actual (Target : Iir) return Iir;
    procedure Set_Actual (Target : Iir; Actual : Iir);
 
+   --  Field: Field3 Ref
+   function Get_Open_Actual (Target : Iir) return Iir;
+   procedure Set_Open_Actual (Target : Iir; Actual : Iir);
+
    --  Field: Field4
    function Get_Actual_Conversion (Target : Iir) return Iir;
    procedure Set_Actual_Conversion (Target : Iir; Conv : Iir);
@@ -8194,6 +8204,10 @@ package Vhdl.Nodes is
    procedure Set_Interface_Declaration_Chain (Target : Iir; Chain : Iir);
    pragma Inline (Get_Interface_Declaration_Chain);
 
+   --  Field: Field9
+   function Get_Default_Subprogram (Inter : Iir) return Iir;
+   procedure Set_Default_Subprogram (Inter : Iir; Subprg : Iir);
+
    --  Field: Field6 Ref
    function Get_Subprogram_Specification (Target : Iir) return Iir;
    procedure Set_Subprogram_Specification (Target : Iir; Spec : Iir);
diff --git a/src/vhdl/vhdl-nodes_meta.adb b/src/vhdl/vhdl-nodes_meta.adb
index 656cc2aef..2d92d3bae 100644
--- a/src/vhdl/vhdl-nodes_meta.adb
+++ b/src/vhdl/vhdl-nodes_meta.adb
@@ -68,6 +68,7 @@ package body Vhdl.Nodes_Meta is
       Field_Designated_Entity => Type_Iir,
       Field_Formal => Type_Iir,
       Field_Actual => Type_Iir,
+      Field_Open_Actual => Type_Iir,
       Field_Actual_Conversion => Type_Iir,
       Field_Formal_Conversion => Type_Iir,
       Field_Whole_Association_Flag => Type_Boolean,
@@ -125,6 +126,7 @@ package body Vhdl.Nodes_Meta is
       Field_Signal_Kind => Type_Iir_Signal_Kind,
       Field_Base_Name => Type_Iir,
       Field_Interface_Declaration_Chain => Type_Iir,
+      Field_Default_Subprogram => Type_Iir,
       Field_Subprogram_Specification => Type_Iir,
       Field_Sequential_Statement_Chain => Type_Iir,
       Field_Simultaneous_Statement_Chain => Type_Iir,
@@ -507,6 +509,8 @@ package body Vhdl.Nodes_Meta is
             return "formal";
          when Field_Actual =>
             return "actual";
+         when Field_Open_Actual =>
+            return "open_actual";
          when Field_Actual_Conversion =>
             return "actual_conversion";
          when Field_Formal_Conversion =>
@@ -621,6 +625,8 @@ package body Vhdl.Nodes_Meta is
             return "base_name";
          when Field_Interface_Declaration_Chain =>
             return "interface_declaration_chain";
+         when Field_Default_Subprogram =>
+            return "default_subprogram";
          when Field_Subprogram_Specification =>
             return "subprogram_specification";
          when Field_Sequential_Statement_Chain =>
@@ -1919,6 +1925,8 @@ package body Vhdl.Nodes_Meta is
             return Attr_None;
          when Field_Actual =>
             return Attr_None;
+         when Field_Open_Actual =>
+            return Attr_Ref;
          when Field_Actual_Conversion =>
             return Attr_None;
          when Field_Formal_Conversion =>
@@ -2033,6 +2041,8 @@ package body Vhdl.Nodes_Meta is
             return Attr_Ref;
          when Field_Interface_Declaration_Chain =>
             return Attr_Chain;
+         when Field_Default_Subprogram =>
+            return Attr_None;
          when Field_Subprogram_Specification =>
             return Attr_Ref;
          when Field_Sequential_Statement_Chain =>
@@ -2740,6 +2750,7 @@ package body Vhdl.Nodes_Meta is
       Field_In_Formal_Flag,
       Field_Formal,
       Field_Chain,
+      Field_Open_Actual,
       --  Iir_Kind_Association_Element_Package
       Field_Whole_Association_Flag,
       Field_Collapse_Signal_Flag,
@@ -3935,6 +3946,7 @@ package body Vhdl.Nodes_Meta is
       Field_Chain,
       Field_Interface_Declaration_Chain,
       Field_Return_Type_Mark,
+      Field_Default_Subprogram,
       --  Iir_Kind_Interface_Procedure_Declaration
       Field_Subprogram_Depth,
       Field_Identifier,
@@ -3950,6 +3962,7 @@ package body Vhdl.Nodes_Meta is
       Field_Chain,
       Field_Interface_Declaration_Chain,
       Field_Return_Type_Mark,
+      Field_Default_Subprogram,
       --  Iir_Kind_Attribute_Implicit_Declaration
       Field_Parent,
       Field_Chain,
@@ -5328,305 +5341,305 @@ package body Vhdl.Nodes_Meta is
       Iir_Kind_Association_Element_By_Expression => 114,
       Iir_Kind_Association_Element_By_Name => 122,
       Iir_Kind_Association_Element_By_Individual => 131,
-      Iir_Kind_Association_Element_Open => 137,
-      Iir_Kind_Association_Element_Package => 143,
-      Iir_Kind_Association_Element_Type => 151,
-      Iir_Kind_Association_Element_Subprogram => 157,
-      Iir_Kind_Association_Element_Terminal => 163,
-      Iir_Kind_Choice_By_Range => 171,
-      Iir_Kind_Choice_By_Expression => 179,
-      Iir_Kind_Choice_By_Others => 185,
-      Iir_Kind_Choice_By_None => 191,
-      Iir_Kind_Choice_By_Name => 198,
-      Iir_Kind_Entity_Aspect_Entity => 200,
-      Iir_Kind_Entity_Aspect_Configuration => 201,
-      Iir_Kind_Entity_Aspect_Open => 201,
-      Iir_Kind_Psl_Hierarchical_Name => 203,
-      Iir_Kind_Block_Configuration => 209,
-      Iir_Kind_Block_Header => 213,
-      Iir_Kind_Component_Configuration => 220,
-      Iir_Kind_Binding_Indication => 224,
-      Iir_Kind_Entity_Class => 226,
-      Iir_Kind_Attribute_Value => 234,
-      Iir_Kind_Signature => 239,
-      Iir_Kind_Aggregate_Info => 246,
-      Iir_Kind_Procedure_Call => 250,
-      Iir_Kind_Record_Element_Constraint => 258,
-      Iir_Kind_Array_Element_Resolution => 260,
-      Iir_Kind_Record_Resolution => 261,
-      Iir_Kind_Record_Element_Resolution => 264,
-      Iir_Kind_Break_Element => 268,
-      Iir_Kind_Attribute_Specification => 277,
-      Iir_Kind_Disconnection_Specification => 283,
-      Iir_Kind_Step_Limit_Specification => 289,
-      Iir_Kind_Configuration_Specification => 295,
-      Iir_Kind_Access_Type_Definition => 302,
-      Iir_Kind_Incomplete_Type_Definition => 309,
-      Iir_Kind_Interface_Type_Definition => 315,
-      Iir_Kind_File_Type_Definition => 321,
-      Iir_Kind_Protected_Type_Declaration => 331,
-      Iir_Kind_Record_Type_Definition => 341,
-      Iir_Kind_Array_Type_Definition => 352,
-      Iir_Kind_Array_Subtype_Definition => 369,
-      Iir_Kind_Record_Subtype_Definition => 382,
-      Iir_Kind_Access_Subtype_Definition => 390,
-      Iir_Kind_Physical_Subtype_Definition => 400,
-      Iir_Kind_Floating_Subtype_Definition => 411,
-      Iir_Kind_Integer_Subtype_Definition => 421,
-      Iir_Kind_Enumeration_Subtype_Definition => 431,
-      Iir_Kind_Enumeration_Type_Definition => 442,
-      Iir_Kind_Integer_Type_Definition => 450,
-      Iir_Kind_Floating_Type_Definition => 458,
-      Iir_Kind_Physical_Type_Definition => 469,
-      Iir_Kind_Range_Expression => 477,
-      Iir_Kind_Protected_Type_Body => 485,
-      Iir_Kind_Wildcard_Type_Definition => 489,
-      Iir_Kind_Foreign_Vector_Type_Definition => 490,
-      Iir_Kind_Subtype_Definition => 497,
-      Iir_Kind_Scalar_Nature_Definition => 505,
-      Iir_Kind_Record_Nature_Definition => 518,
-      Iir_Kind_Array_Nature_Definition => 532,
-      Iir_Kind_Array_Subnature_Definition => 547,
-      Iir_Kind_Overload_List => 548,
-      Iir_Kind_Foreign_Module => 553,
-      Iir_Kind_Entity_Declaration => 566,
-      Iir_Kind_Configuration_Declaration => 576,
-      Iir_Kind_Context_Declaration => 582,
-      Iir_Kind_Package_Declaration => 597,
-      Iir_Kind_Package_Instantiation_Declaration => 611,
-      Iir_Kind_Vmode_Declaration => 623,
-      Iir_Kind_Vprop_Declaration => 635,
-      Iir_Kind_Vunit_Declaration => 648,
-      Iir_Kind_Package_Body => 656,
-      Iir_Kind_Architecture_Body => 669,
-      Iir_Kind_Type_Declaration => 676,
-      Iir_Kind_Anonymous_Type_Declaration => 682,
-      Iir_Kind_Subtype_Declaration => 690,
-      Iir_Kind_Nature_Declaration => 696,
-      Iir_Kind_Subnature_Declaration => 703,
-      Iir_Kind_Package_Header => 705,
-      Iir_Kind_Unit_Declaration => 714,
-      Iir_Kind_Library_Declaration => 722,
-      Iir_Kind_Component_Declaration => 732,
-      Iir_Kind_Attribute_Declaration => 739,
-      Iir_Kind_Group_Template_Declaration => 745,
-      Iir_Kind_Group_Declaration => 752,
-      Iir_Kind_Element_Declaration => 760,
-      Iir_Kind_Nature_Element_Declaration => 767,
-      Iir_Kind_Non_Object_Alias_Declaration => 775,
-      Iir_Kind_Psl_Declaration => 783,
-      Iir_Kind_Psl_Endpoint_Declaration => 797,
-      Iir_Kind_Enumeration_Literal => 809,
-      Iir_Kind_Function_Declaration => 835,
-      Iir_Kind_Procedure_Declaration => 858,
-      Iir_Kind_Function_Body => 868,
-      Iir_Kind_Procedure_Body => 879,
-      Iir_Kind_Function_Instantiation_Declaration => 890,
-      Iir_Kind_Procedure_Instantiation_Declaration => 900,
-      Iir_Kind_Terminal_Declaration => 910,
-      Iir_Kind_Object_Alias_Declaration => 922,
-      Iir_Kind_Free_Quantity_Declaration => 934,
-      Iir_Kind_Spectrum_Quantity_Declaration => 947,
-      Iir_Kind_Noise_Quantity_Declaration => 959,
-      Iir_Kind_Across_Quantity_Declaration => 975,
-      Iir_Kind_Through_Quantity_Declaration => 991,
-      Iir_Kind_File_Declaration => 1006,
-      Iir_Kind_Guard_Signal_Declaration => 1020,
-      Iir_Kind_Signal_Declaration => 1037,
-      Iir_Kind_Variable_Declaration => 1050,
-      Iir_Kind_Constant_Declaration => 1064,
-      Iir_Kind_Iterator_Declaration => 1076,
-      Iir_Kind_Interface_Constant_Declaration => 1093,
-      Iir_Kind_Interface_Variable_Declaration => 1109,
-      Iir_Kind_Interface_Signal_Declaration => 1130,
-      Iir_Kind_Interface_File_Declaration => 1146,
-      Iir_Kind_Interface_Quantity_Declaration => 1162,
-      Iir_Kind_Interface_Terminal_Declaration => 1174,
-      Iir_Kind_Interface_Type_Declaration => 1185,
-      Iir_Kind_Interface_Package_Declaration => 1198,
-      Iir_Kind_Interface_Function_Declaration => 1216,
-      Iir_Kind_Interface_Procedure_Declaration => 1230,
-      Iir_Kind_Attribute_Implicit_Declaration => 1233,
-      Iir_Kind_Suspend_State_Declaration => 1236,
-      Iir_Kind_Identity_Operator => 1240,
-      Iir_Kind_Negation_Operator => 1244,
-      Iir_Kind_Absolute_Operator => 1248,
-      Iir_Kind_Not_Operator => 1252,
-      Iir_Kind_Implicit_Condition_Operator => 1256,
-      Iir_Kind_Condition_Operator => 1260,
-      Iir_Kind_Reduction_And_Operator => 1264,
-      Iir_Kind_Reduction_Or_Operator => 1268,
-      Iir_Kind_Reduction_Nand_Operator => 1272,
-      Iir_Kind_Reduction_Nor_Operator => 1276,
-      Iir_Kind_Reduction_Xor_Operator => 1280,
-      Iir_Kind_Reduction_Xnor_Operator => 1284,
-      Iir_Kind_And_Operator => 1289,
-      Iir_Kind_Or_Operator => 1294,
-      Iir_Kind_Nand_Operator => 1299,
-      Iir_Kind_Nor_Operator => 1304,
-      Iir_Kind_Xor_Operator => 1309,
-      Iir_Kind_Xnor_Operator => 1314,
-      Iir_Kind_Equality_Operator => 1319,
-      Iir_Kind_Inequality_Operator => 1324,
-      Iir_Kind_Less_Than_Operator => 1329,
-      Iir_Kind_Less_Than_Or_Equal_Operator => 1334,
-      Iir_Kind_Greater_Than_Operator => 1339,
-      Iir_Kind_Greater_Than_Or_Equal_Operator => 1344,
-      Iir_Kind_Match_Equality_Operator => 1349,
-      Iir_Kind_Match_Inequality_Operator => 1354,
-      Iir_Kind_Match_Less_Than_Operator => 1359,
-      Iir_Kind_Match_Less_Than_Or_Equal_Operator => 1364,
-      Iir_Kind_Match_Greater_Than_Operator => 1369,
-      Iir_Kind_Match_Greater_Than_Or_Equal_Operator => 1374,
-      Iir_Kind_Sll_Operator => 1379,
-      Iir_Kind_Sla_Operator => 1384,
-      Iir_Kind_Srl_Operator => 1389,
-      Iir_Kind_Sra_Operator => 1394,
-      Iir_Kind_Rol_Operator => 1399,
-      Iir_Kind_Ror_Operator => 1404,
-      Iir_Kind_Addition_Operator => 1409,
-      Iir_Kind_Substraction_Operator => 1414,
-      Iir_Kind_Concatenation_Operator => 1419,
-      Iir_Kind_Multiplication_Operator => 1424,
-      Iir_Kind_Division_Operator => 1429,
-      Iir_Kind_Modulus_Operator => 1434,
-      Iir_Kind_Remainder_Operator => 1439,
-      Iir_Kind_Exponentiation_Operator => 1444,
-      Iir_Kind_Function_Call => 1452,
-      Iir_Kind_Aggregate => 1459,
-      Iir_Kind_Parenthesis_Expression => 1462,
-      Iir_Kind_Qualified_Expression => 1466,
-      Iir_Kind_Type_Conversion => 1471,
-      Iir_Kind_Allocator_By_Expression => 1476,
-      Iir_Kind_Allocator_By_Subtype => 1482,
-      Iir_Kind_Selected_Element => 1490,
-      Iir_Kind_Dereference => 1495,
-      Iir_Kind_Implicit_Dereference => 1500,
-      Iir_Kind_Slice_Name => 1507,
-      Iir_Kind_Indexed_Name => 1513,
-      Iir_Kind_Psl_Prev => 1519,
-      Iir_Kind_Psl_Stable => 1524,
-      Iir_Kind_Psl_Rose => 1529,
-      Iir_Kind_Psl_Fell => 1534,
-      Iir_Kind_Psl_Onehot => 1537,
-      Iir_Kind_Psl_Onehot0 => 1540,
-      Iir_Kind_Psl_Expression => 1542,
-      Iir_Kind_Sensitized_Process_Statement => 1564,
-      Iir_Kind_Process_Statement => 1585,
-      Iir_Kind_Concurrent_Simple_Signal_Assignment => 1598,
-      Iir_Kind_Concurrent_Conditional_Signal_Assignment => 1611,
-      Iir_Kind_Concurrent_Selected_Signal_Assignment => 1625,
-      Iir_Kind_Concurrent_Assertion_Statement => 1633,
-      Iir_Kind_Concurrent_Procedure_Call_Statement => 1640,
-      Iir_Kind_Concurrent_Break_Statement => 1648,
-      Iir_Kind_Psl_Assert_Directive => 1662,
-      Iir_Kind_Psl_Assume_Directive => 1674,
-      Iir_Kind_Psl_Cover_Directive => 1686,
-      Iir_Kind_Psl_Restrict_Directive => 1697,
-      Iir_Kind_Block_Statement => 1711,
-      Iir_Kind_If_Generate_Statement => 1722,
-      Iir_Kind_Case_Generate_Statement => 1731,
-      Iir_Kind_For_Generate_Statement => 1740,
-      Iir_Kind_Component_Instantiation_Statement => 1751,
-      Iir_Kind_Psl_Default_Clock => 1754,
-      Iir_Kind_Generate_Statement_Body => 1765,
-      Iir_Kind_If_Generate_Else_Clause => 1771,
-      Iir_Kind_Simple_Simultaneous_Statement => 1778,
-      Iir_Kind_Simultaneous_Null_Statement => 1782,
-      Iir_Kind_Simultaneous_Procedural_Statement => 1793,
-      Iir_Kind_Simultaneous_Case_Statement => 1802,
-      Iir_Kind_Simultaneous_If_Statement => 1811,
-      Iir_Kind_Simultaneous_Elsif => 1817,
-      Iir_Kind_Simple_Signal_Assignment_Statement => 1828,
-      Iir_Kind_Conditional_Signal_Assignment_Statement => 1839,
-      Iir_Kind_Selected_Waveform_Assignment_Statement => 1851,
-      Iir_Kind_Signal_Force_Assignment_Statement => 1861,
-      Iir_Kind_Signal_Release_Assignment_Statement => 1870,
-      Iir_Kind_Null_Statement => 1874,
-      Iir_Kind_Assertion_Statement => 1881,
-      Iir_Kind_Report_Statement => 1887,
-      Iir_Kind_Wait_Statement => 1895,
-      Iir_Kind_Variable_Assignment_Statement => 1902,
-      Iir_Kind_Conditional_Variable_Assignment_Statement => 1909,
-      Iir_Kind_Return_Statement => 1915,
-      Iir_Kind_For_Loop_Statement => 1926,
-      Iir_Kind_While_Loop_Statement => 1937,
-      Iir_Kind_Next_Statement => 1944,
-      Iir_Kind_Exit_Statement => 1951,
-      Iir_Kind_Case_Statement => 1960,
-      Iir_Kind_Procedure_Call_Statement => 1966,
-      Iir_Kind_Break_Statement => 1973,
-      Iir_Kind_If_Statement => 1983,
-      Iir_Kind_Suspend_State_Statement => 1987,
-      Iir_Kind_Elsif => 1993,
-      Iir_Kind_Character_Literal => 2000,
-      Iir_Kind_Simple_Name => 2007,
-      Iir_Kind_Selected_Name => 2015,
-      Iir_Kind_Operator_Symbol => 2020,
-      Iir_Kind_Reference_Name => 2025,
-      Iir_Kind_External_Constant_Name => 2034,
-      Iir_Kind_External_Signal_Name => 2043,
-      Iir_Kind_External_Variable_Name => 2053,
-      Iir_Kind_Selected_By_All_Name => 2059,
-      Iir_Kind_Parenthesis_Name => 2064,
-      Iir_Kind_Package_Pathname => 2068,
-      Iir_Kind_Absolute_Pathname => 2069,
-      Iir_Kind_Relative_Pathname => 2070,
-      Iir_Kind_Pathname_Element => 2075,
-      Iir_Kind_Base_Attribute => 2077,
-      Iir_Kind_Subtype_Attribute => 2082,
-      Iir_Kind_Element_Attribute => 2087,
-      Iir_Kind_Across_Attribute => 2092,
-      Iir_Kind_Through_Attribute => 2097,
-      Iir_Kind_Nature_Reference_Attribute => 2101,
-      Iir_Kind_Left_Type_Attribute => 2106,
-      Iir_Kind_Right_Type_Attribute => 2111,
-      Iir_Kind_High_Type_Attribute => 2116,
-      Iir_Kind_Low_Type_Attribute => 2121,
-      Iir_Kind_Ascending_Type_Attribute => 2126,
-      Iir_Kind_Image_Attribute => 2132,
-      Iir_Kind_Value_Attribute => 2138,
-      Iir_Kind_Pos_Attribute => 2144,
-      Iir_Kind_Val_Attribute => 2150,
-      Iir_Kind_Succ_Attribute => 2156,
-      Iir_Kind_Pred_Attribute => 2162,
-      Iir_Kind_Leftof_Attribute => 2168,
-      Iir_Kind_Rightof_Attribute => 2174,
-      Iir_Kind_Signal_Slew_Attribute => 2182,
-      Iir_Kind_Quantity_Slew_Attribute => 2190,
-      Iir_Kind_Ramp_Attribute => 2198,
-      Iir_Kind_Zoh_Attribute => 2206,
-      Iir_Kind_Ltf_Attribute => 2214,
-      Iir_Kind_Ztf_Attribute => 2224,
-      Iir_Kind_Dot_Attribute => 2231,
-      Iir_Kind_Integ_Attribute => 2238,
-      Iir_Kind_Quantity_Delayed_Attribute => 2246,
-      Iir_Kind_Above_Attribute => 2254,
-      Iir_Kind_Delayed_Attribute => 2263,
-      Iir_Kind_Stable_Attribute => 2272,
-      Iir_Kind_Quiet_Attribute => 2281,
-      Iir_Kind_Transaction_Attribute => 2290,
-      Iir_Kind_Event_Attribute => 2294,
-      Iir_Kind_Active_Attribute => 2298,
-      Iir_Kind_Last_Event_Attribute => 2302,
-      Iir_Kind_Last_Active_Attribute => 2306,
-      Iir_Kind_Last_Value_Attribute => 2310,
-      Iir_Kind_Driving_Attribute => 2314,
-      Iir_Kind_Driving_Value_Attribute => 2318,
-      Iir_Kind_Behavior_Attribute => 2318,
-      Iir_Kind_Structure_Attribute => 2318,
-      Iir_Kind_Simple_Name_Attribute => 2325,
-      Iir_Kind_Instance_Name_Attribute => 2330,
-      Iir_Kind_Path_Name_Attribute => 2335,
-      Iir_Kind_Left_Array_Attribute => 2342,
-      Iir_Kind_Right_Array_Attribute => 2349,
-      Iir_Kind_High_Array_Attribute => 2356,
-      Iir_Kind_Low_Array_Attribute => 2363,
-      Iir_Kind_Length_Array_Attribute => 2370,
-      Iir_Kind_Ascending_Array_Attribute => 2377,
-      Iir_Kind_Range_Array_Attribute => 2384,
-      Iir_Kind_Reverse_Range_Array_Attribute => 2391,
-      Iir_Kind_Attribute_Name => 2400
+      Iir_Kind_Association_Element_Open => 138,
+      Iir_Kind_Association_Element_Package => 144,
+      Iir_Kind_Association_Element_Type => 152,
+      Iir_Kind_Association_Element_Subprogram => 158,
+      Iir_Kind_Association_Element_Terminal => 164,
+      Iir_Kind_Choice_By_Range => 172,
+      Iir_Kind_Choice_By_Expression => 180,
+      Iir_Kind_Choice_By_Others => 186,
+      Iir_Kind_Choice_By_None => 192,
+      Iir_Kind_Choice_By_Name => 199,
+      Iir_Kind_Entity_Aspect_Entity => 201,
+      Iir_Kind_Entity_Aspect_Configuration => 202,
+      Iir_Kind_Entity_Aspect_Open => 202,
+      Iir_Kind_Psl_Hierarchical_Name => 204,
+      Iir_Kind_Block_Configuration => 210,
+      Iir_Kind_Block_Header => 214,
+      Iir_Kind_Component_Configuration => 221,
+      Iir_Kind_Binding_Indication => 225,
+      Iir_Kind_Entity_Class => 227,
+      Iir_Kind_Attribute_Value => 235,
+      Iir_Kind_Signature => 240,
+      Iir_Kind_Aggregate_Info => 247,
+      Iir_Kind_Procedure_Call => 251,
+      Iir_Kind_Record_Element_Constraint => 259,
+      Iir_Kind_Array_Element_Resolution => 261,
+      Iir_Kind_Record_Resolution => 262,
+      Iir_Kind_Record_Element_Resolution => 265,
+      Iir_Kind_Break_Element => 269,
+      Iir_Kind_Attribute_Specification => 278,
+      Iir_Kind_Disconnection_Specification => 284,
+      Iir_Kind_Step_Limit_Specification => 290,
+      Iir_Kind_Configuration_Specification => 296,
+      Iir_Kind_Access_Type_Definition => 303,
+      Iir_Kind_Incomplete_Type_Definition => 310,
+      Iir_Kind_Interface_Type_Definition => 316,
+      Iir_Kind_File_Type_Definition => 322,
+      Iir_Kind_Protected_Type_Declaration => 332,
+      Iir_Kind_Record_Type_Definition => 342,
+      Iir_Kind_Array_Type_Definition => 353,
+      Iir_Kind_Array_Subtype_Definition => 370,
+      Iir_Kind_Record_Subtype_Definition => 383,
+      Iir_Kind_Access_Subtype_Definition => 391,
+      Iir_Kind_Physical_Subtype_Definition => 401,
+      Iir_Kind_Floating_Subtype_Definition => 412,
+      Iir_Kind_Integer_Subtype_Definition => 422,
+      Iir_Kind_Enumeration_Subtype_Definition => 432,
+      Iir_Kind_Enumeration_Type_Definition => 443,
+      Iir_Kind_Integer_Type_Definition => 451,
+      Iir_Kind_Floating_Type_Definition => 459,
+      Iir_Kind_Physical_Type_Definition => 470,
+      Iir_Kind_Range_Expression => 478,
+      Iir_Kind_Protected_Type_Body => 486,
+      Iir_Kind_Wildcard_Type_Definition => 490,
+      Iir_Kind_Foreign_Vector_Type_Definition => 491,
+      Iir_Kind_Subtype_Definition => 498,
+      Iir_Kind_Scalar_Nature_Definition => 506,
+      Iir_Kind_Record_Nature_Definition => 519,
+      Iir_Kind_Array_Nature_Definition => 533,
+      Iir_Kind_Array_Subnature_Definition => 548,
+      Iir_Kind_Overload_List => 549,
+      Iir_Kind_Foreign_Module => 554,
+      Iir_Kind_Entity_Declaration => 567,
+      Iir_Kind_Configuration_Declaration => 577,
+      Iir_Kind_Context_Declaration => 583,
+      Iir_Kind_Package_Declaration => 598,
+      Iir_Kind_Package_Instantiation_Declaration => 612,
+      Iir_Kind_Vmode_Declaration => 624,
+      Iir_Kind_Vprop_Declaration => 636,
+      Iir_Kind_Vunit_Declaration => 649,
+      Iir_Kind_Package_Body => 657,
+      Iir_Kind_Architecture_Body => 670,
+      Iir_Kind_Type_Declaration => 677,
+      Iir_Kind_Anonymous_Type_Declaration => 683,
+      Iir_Kind_Subtype_Declaration => 691,
+      Iir_Kind_Nature_Declaration => 697,
+      Iir_Kind_Subnature_Declaration => 704,
+      Iir_Kind_Package_Header => 706,
+      Iir_Kind_Unit_Declaration => 715,
+      Iir_Kind_Library_Declaration => 723,
+      Iir_Kind_Component_Declaration => 733,
+      Iir_Kind_Attribute_Declaration => 740,
+      Iir_Kind_Group_Template_Declaration => 746,
+      Iir_Kind_Group_Declaration => 753,
+      Iir_Kind_Element_Declaration => 761,
+      Iir_Kind_Nature_Element_Declaration => 768,
+      Iir_Kind_Non_Object_Alias_Declaration => 776,
+      Iir_Kind_Psl_Declaration => 784,
+      Iir_Kind_Psl_Endpoint_Declaration => 798,
+      Iir_Kind_Enumeration_Literal => 810,
+      Iir_Kind_Function_Declaration => 836,
+      Iir_Kind_Procedure_Declaration => 859,
+      Iir_Kind_Function_Body => 869,
+      Iir_Kind_Procedure_Body => 880,
+      Iir_Kind_Function_Instantiation_Declaration => 891,
+      Iir_Kind_Procedure_Instantiation_Declaration => 901,
+      Iir_Kind_Terminal_Declaration => 911,
+      Iir_Kind_Object_Alias_Declaration => 923,
+      Iir_Kind_Free_Quantity_Declaration => 935,
+      Iir_Kind_Spectrum_Quantity_Declaration => 948,
+      Iir_Kind_Noise_Quantity_Declaration => 960,
+      Iir_Kind_Across_Quantity_Declaration => 976,
+      Iir_Kind_Through_Quantity_Declaration => 992,
+      Iir_Kind_File_Declaration => 1007,
+      Iir_Kind_Guard_Signal_Declaration => 1021,
+      Iir_Kind_Signal_Declaration => 1038,
+      Iir_Kind_Variable_Declaration => 1051,
+      Iir_Kind_Constant_Declaration => 1065,
+      Iir_Kind_Iterator_Declaration => 1077,
+      Iir_Kind_Interface_Constant_Declaration => 1094,
+      Iir_Kind_Interface_Variable_Declaration => 1110,
+      Iir_Kind_Interface_Signal_Declaration => 1131,
+      Iir_Kind_Interface_File_Declaration => 1147,
+      Iir_Kind_Interface_Quantity_Declaration => 1163,
+      Iir_Kind_Interface_Terminal_Declaration => 1175,
+      Iir_Kind_Interface_Type_Declaration => 1186,
+      Iir_Kind_Interface_Package_Declaration => 1199,
+      Iir_Kind_Interface_Function_Declaration => 1218,
+      Iir_Kind_Interface_Procedure_Declaration => 1233,
+      Iir_Kind_Attribute_Implicit_Declaration => 1236,
+      Iir_Kind_Suspend_State_Declaration => 1239,
+      Iir_Kind_Identity_Operator => 1243,
+      Iir_Kind_Negation_Operator => 1247,
+      Iir_Kind_Absolute_Operator => 1251,
+      Iir_Kind_Not_Operator => 1255,
+      Iir_Kind_Implicit_Condition_Operator => 1259,
+      Iir_Kind_Condition_Operator => 1263,
+      Iir_Kind_Reduction_And_Operator => 1267,
+      Iir_Kind_Reduction_Or_Operator => 1271,
+      Iir_Kind_Reduction_Nand_Operator => 1275,
+      Iir_Kind_Reduction_Nor_Operator => 1279,
+      Iir_Kind_Reduction_Xor_Operator => 1283,
+      Iir_Kind_Reduction_Xnor_Operator => 1287,
+      Iir_Kind_And_Operator => 1292,
+      Iir_Kind_Or_Operator => 1297,
+      Iir_Kind_Nand_Operator => 1302,
+      Iir_Kind_Nor_Operator => 1307,
+      Iir_Kind_Xor_Operator => 1312,
+      Iir_Kind_Xnor_Operator => 1317,
+      Iir_Kind_Equality_Operator => 1322,
+      Iir_Kind_Inequality_Operator => 1327,
+      Iir_Kind_Less_Than_Operator => 1332,
+      Iir_Kind_Less_Than_Or_Equal_Operator => 1337,
+      Iir_Kind_Greater_Than_Operator => 1342,
+      Iir_Kind_Greater_Than_Or_Equal_Operator => 1347,
+      Iir_Kind_Match_Equality_Operator => 1352,
+      Iir_Kind_Match_Inequality_Operator => 1357,
+      Iir_Kind_Match_Less_Than_Operator => 1362,
+      Iir_Kind_Match_Less_Than_Or_Equal_Operator => 1367,
+      Iir_Kind_Match_Greater_Than_Operator => 1372,
+      Iir_Kind_Match_Greater_Than_Or_Equal_Operator => 1377,
+      Iir_Kind_Sll_Operator => 1382,
+      Iir_Kind_Sla_Operator => 1387,
+      Iir_Kind_Srl_Operator => 1392,
+      Iir_Kind_Sra_Operator => 1397,
+      Iir_Kind_Rol_Operator => 1402,
+      Iir_Kind_Ror_Operator => 1407,
+      Iir_Kind_Addition_Operator => 1412,
+      Iir_Kind_Substraction_Operator => 1417,
+      Iir_Kind_Concatenation_Operator => 1422,
+      Iir_Kind_Multiplication_Operator => 1427,
+      Iir_Kind_Division_Operator => 1432,
+      Iir_Kind_Modulus_Operator => 1437,
+      Iir_Kind_Remainder_Operator => 1442,
+      Iir_Kind_Exponentiation_Operator => 1447,
+      Iir_Kind_Function_Call => 1455,
+      Iir_Kind_Aggregate => 1462,
+      Iir_Kind_Parenthesis_Expression => 1465,
+      Iir_Kind_Qualified_Expression => 1469,
+      Iir_Kind_Type_Conversion => 1474,
+      Iir_Kind_Allocator_By_Expression => 1479,
+      Iir_Kind_Allocator_By_Subtype => 1485,
+      Iir_Kind_Selected_Element => 1493,
+      Iir_Kind_Dereference => 1498,
+      Iir_Kind_Implicit_Dereference => 1503,
+      Iir_Kind_Slice_Name => 1510,
+      Iir_Kind_Indexed_Name => 1516,
+      Iir_Kind_Psl_Prev => 1522,
+      Iir_Kind_Psl_Stable => 1527,
+      Iir_Kind_Psl_Rose => 1532,
+      Iir_Kind_Psl_Fell => 1537,
+      Iir_Kind_Psl_Onehot => 1540,
+      Iir_Kind_Psl_Onehot0 => 1543,
+      Iir_Kind_Psl_Expression => 1545,
+      Iir_Kind_Sensitized_Process_Statement => 1567,
+      Iir_Kind_Process_Statement => 1588,
+      Iir_Kind_Concurrent_Simple_Signal_Assignment => 1601,
+      Iir_Kind_Concurrent_Conditional_Signal_Assignment => 1614,
+      Iir_Kind_Concurrent_Selected_Signal_Assignment => 1628,
+      Iir_Kind_Concurrent_Assertion_Statement => 1636,
+      Iir_Kind_Concurrent_Procedure_Call_Statement => 1643,
+      Iir_Kind_Concurrent_Break_Statement => 1651,
+      Iir_Kind_Psl_Assert_Directive => 1665,
+      Iir_Kind_Psl_Assume_Directive => 1677,
+      Iir_Kind_Psl_Cover_Directive => 1689,
+      Iir_Kind_Psl_Restrict_Directive => 1700,
+      Iir_Kind_Block_Statement => 1714,
+      Iir_Kind_If_Generate_Statement => 1725,
+      Iir_Kind_Case_Generate_Statement => 1734,
+      Iir_Kind_For_Generate_Statement => 1743,
+      Iir_Kind_Component_Instantiation_Statement => 1754,
+      Iir_Kind_Psl_Default_Clock => 1757,
+      Iir_Kind_Generate_Statement_Body => 1768,
+      Iir_Kind_If_Generate_Else_Clause => 1774,
+      Iir_Kind_Simple_Simultaneous_Statement => 1781,
+      Iir_Kind_Simultaneous_Null_Statement => 1785,
+      Iir_Kind_Simultaneous_Procedural_Statement => 1796,
+      Iir_Kind_Simultaneous_Case_Statement => 1805,
+      Iir_Kind_Simultaneous_If_Statement => 1814,
+      Iir_Kind_Simultaneous_Elsif => 1820,
+      Iir_Kind_Simple_Signal_Assignment_Statement => 1831,
+      Iir_Kind_Conditional_Signal_Assignment_Statement => 1842,
+      Iir_Kind_Selected_Waveform_Assignment_Statement => 1854,
+      Iir_Kind_Signal_Force_Assignment_Statement => 1864,
+      Iir_Kind_Signal_Release_Assignment_Statement => 1873,
+      Iir_Kind_Null_Statement => 1877,
+      Iir_Kind_Assertion_Statement => 1884,
+      Iir_Kind_Report_Statement => 1890,
+      Iir_Kind_Wait_Statement => 1898,
+      Iir_Kind_Variable_Assignment_Statement => 1905,
+      Iir_Kind_Conditional_Variable_Assignment_Statement => 1912,
+      Iir_Kind_Return_Statement => 1918,
+      Iir_Kind_For_Loop_Statement => 1929,
+      Iir_Kind_While_Loop_Statement => 1940,
+      Iir_Kind_Next_Statement => 1947,
+      Iir_Kind_Exit_Statement => 1954,
+      Iir_Kind_Case_Statement => 1963,
+      Iir_Kind_Procedure_Call_Statement => 1969,
+      Iir_Kind_Break_Statement => 1976,
+      Iir_Kind_If_Statement => 1986,
+      Iir_Kind_Suspend_State_Statement => 1990,
+      Iir_Kind_Elsif => 1996,
+      Iir_Kind_Character_Literal => 2003,
+      Iir_Kind_Simple_Name => 2010,
+      Iir_Kind_Selected_Name => 2018,
+      Iir_Kind_Operator_Symbol => 2023,
+      Iir_Kind_Reference_Name => 2028,
+      Iir_Kind_External_Constant_Name => 2037,
+      Iir_Kind_External_Signal_Name => 2046,
+      Iir_Kind_External_Variable_Name => 2056,
+      Iir_Kind_Selected_By_All_Name => 2062,
+      Iir_Kind_Parenthesis_Name => 2067,
+      Iir_Kind_Package_Pathname => 2071,
+      Iir_Kind_Absolute_Pathname => 2072,
+      Iir_Kind_Relative_Pathname => 2073,
+      Iir_Kind_Pathname_Element => 2078,
+      Iir_Kind_Base_Attribute => 2080,
+      Iir_Kind_Subtype_Attribute => 2085,
+      Iir_Kind_Element_Attribute => 2090,
+      Iir_Kind_Across_Attribute => 2095,
+      Iir_Kind_Through_Attribute => 2100,
+      Iir_Kind_Nature_Reference_Attribute => 2104,
+      Iir_Kind_Left_Type_Attribute => 2109,
+      Iir_Kind_Right_Type_Attribute => 2114,
+      Iir_Kind_High_Type_Attribute => 2119,
+      Iir_Kind_Low_Type_Attribute => 2124,
+      Iir_Kind_Ascending_Type_Attribute => 2129,
+      Iir_Kind_Image_Attribute => 2135,
+      Iir_Kind_Value_Attribute => 2141,
+      Iir_Kind_Pos_Attribute => 2147,
+      Iir_Kind_Val_Attribute => 2153,
+      Iir_Kind_Succ_Attribute => 2159,
+      Iir_Kind_Pred_Attribute => 2165,
+      Iir_Kind_Leftof_Attribute => 2171,
+      Iir_Kind_Rightof_Attribute => 2177,
+      Iir_Kind_Signal_Slew_Attribute => 2185,
+      Iir_Kind_Quantity_Slew_Attribute => 2193,
+      Iir_Kind_Ramp_Attribute => 2201,
+      Iir_Kind_Zoh_Attribute => 2209,
+      Iir_Kind_Ltf_Attribute => 2217,
+      Iir_Kind_Ztf_Attribute => 2227,
+      Iir_Kind_Dot_Attribute => 2234,
+      Iir_Kind_Integ_Attribute => 2241,
+      Iir_Kind_Quantity_Delayed_Attribute => 2249,
+      Iir_Kind_Above_Attribute => 2257,
+      Iir_Kind_Delayed_Attribute => 2266,
+      Iir_Kind_Stable_Attribute => 2275,
+      Iir_Kind_Quiet_Attribute => 2284,
+      Iir_Kind_Transaction_Attribute => 2293,
+      Iir_Kind_Event_Attribute => 2297,
+      Iir_Kind_Active_Attribute => 2301,
+      Iir_Kind_Last_Event_Attribute => 2305,
+      Iir_Kind_Last_Active_Attribute => 2309,
+      Iir_Kind_Last_Value_Attribute => 2313,
+      Iir_Kind_Driving_Attribute => 2317,
+      Iir_Kind_Driving_Value_Attribute => 2321,
+      Iir_Kind_Behavior_Attribute => 2321,
+      Iir_Kind_Structure_Attribute => 2321,
+      Iir_Kind_Simple_Name_Attribute => 2328,
+      Iir_Kind_Instance_Name_Attribute => 2333,
+      Iir_Kind_Path_Name_Attribute => 2338,
+      Iir_Kind_Left_Array_Attribute => 2345,
+      Iir_Kind_Right_Array_Attribute => 2352,
+      Iir_Kind_High_Array_Attribute => 2359,
+      Iir_Kind_Low_Array_Attribute => 2366,
+      Iir_Kind_Length_Array_Attribute => 2373,
+      Iir_Kind_Ascending_Array_Attribute => 2380,
+      Iir_Kind_Range_Array_Attribute => 2387,
+      Iir_Kind_Reverse_Range_Array_Attribute => 2394,
+      Iir_Kind_Attribute_Name => 2403
      );
 
    function Get_Fields_First (K : Iir_Kind) return Fields_Index is
@@ -6141,6 +6154,8 @@ package body Vhdl.Nodes_Meta is
             return Get_Formal (N);
          when Field_Actual =>
             return Get_Actual (N);
+         when Field_Open_Actual =>
+            return Get_Open_Actual (N);
          when Field_Actual_Conversion =>
             return Get_Actual_Conversion (N);
          when Field_Formal_Conversion =>
@@ -6227,6 +6242,8 @@ package body Vhdl.Nodes_Meta is
             return Get_Base_Name (N);
          when Field_Interface_Declaration_Chain =>
             return Get_Interface_Declaration_Chain (N);
+         when Field_Default_Subprogram =>
+            return Get_Default_Subprogram (N);
          when Field_Subprogram_Specification =>
             return Get_Subprogram_Specification (N);
          when Field_Sequential_Statement_Chain =>
@@ -6601,6 +6618,8 @@ package body Vhdl.Nodes_Meta is
             Set_Formal (N, V);
          when Field_Actual =>
             Set_Actual (N, V);
+         when Field_Open_Actual =>
+            Set_Open_Actual (N, V);
          when Field_Actual_Conversion =>
             Set_Actual_Conversion (N, V);
          when Field_Formal_Conversion =>
@@ -6687,6 +6706,8 @@ package body Vhdl.Nodes_Meta is
             Set_Base_Name (N, V);
          when Field_Interface_Declaration_Chain =>
             Set_Interface_Declaration_Chain (N, V);
+         when Field_Default_Subprogram =>
+            Set_Default_Subprogram (N, V);
          when Field_Subprogram_Specification =>
             Set_Subprogram_Specification (N, V);
          when Field_Sequential_Statement_Chain =>
@@ -8177,6 +8198,11 @@ package body Vhdl.Nodes_Meta is
       end case;
    end Has_Actual;
 
+   function Has_Open_Actual (K : Iir_Kind) return Boolean is
+   begin
+      return K = Iir_Kind_Association_Element_Open;
+   end Has_Open_Actual;
+
    function Has_Actual_Conversion (K : Iir_Kind) return Boolean is
    begin
       case K is
@@ -9121,6 +9147,17 @@ package body Vhdl.Nodes_Meta is
       end case;
    end Has_Interface_Declaration_Chain;
 
+   function Has_Default_Subprogram (K : Iir_Kind) return Boolean is
+   begin
+      case K is
+         when Iir_Kind_Interface_Function_Declaration
+           | Iir_Kind_Interface_Procedure_Declaration =>
+            return True;
+         when others =>
+            return False;
+      end case;
+   end Has_Default_Subprogram;
+
    function Has_Subprogram_Specification (K : Iir_Kind) return Boolean is
    begin
       case K is
diff --git a/src/vhdl/vhdl-nodes_meta.ads b/src/vhdl/vhdl-nodes_meta.ads
index 538c40910..214f2f067 100644
--- a/src/vhdl/vhdl-nodes_meta.ads
+++ b/src/vhdl/vhdl-nodes_meta.ads
@@ -112,6 +112,7 @@ package Vhdl.Nodes_Meta is
       Field_Designated_Entity,
       Field_Formal,
       Field_Actual,
+      Field_Open_Actual,
       Field_Actual_Conversion,
       Field_Formal_Conversion,
       Field_Whole_Association_Flag,
@@ -169,6 +170,7 @@ package Vhdl.Nodes_Meta is
       Field_Signal_Kind,
       Field_Base_Name,
       Field_Interface_Declaration_Chain,
+      Field_Default_Subprogram,
       Field_Subprogram_Specification,
       Field_Sequential_Statement_Chain,
       Field_Simultaneous_Statement_Chain,
@@ -702,6 +704,7 @@ package Vhdl.Nodes_Meta is
    function Has_Designated_Entity (K : Iir_Kind) return Boolean;
    function Has_Formal (K : Iir_Kind) return Boolean;
    function Has_Actual (K : Iir_Kind) return Boolean;
+   function Has_Open_Actual (K : Iir_Kind) return Boolean;
    function Has_Actual_Conversion (K : Iir_Kind) return Boolean;
    function Has_Formal_Conversion (K : Iir_Kind) return Boolean;
    function Has_Whole_Association_Flag (K : Iir_Kind) return Boolean;
@@ -760,6 +763,7 @@ package Vhdl.Nodes_Meta is
    function Has_Signal_Kind (K : Iir_Kind) return Boolean;
    function Has_Base_Name (K : Iir_Kind) return Boolean;
    function Has_Interface_Declaration_Chain (K : Iir_Kind) return Boolean;
+   function Has_Default_Subprogram (K : Iir_Kind) return Boolean;
    function Has_Subprogram_Specification (K : Iir_Kind) return Boolean;
    function Has_Sequential_Statement_Chain (K : Iir_Kind) return Boolean;
    function Has_Simultaneous_Statement_Chain (K : Iir_Kind) return Boolean;
diff --git a/src/vhdl/vhdl-parse.adb b/src/vhdl/vhdl-parse.adb
index 4f8ac27c0..177d46f88 100644
--- a/src/vhdl/vhdl-parse.adb
+++ b/src/vhdl/vhdl-parse.adb
@@ -2206,6 +2206,7 @@ package body Vhdl.Parse is
       Subprg: Iir;
       Old : Iir;
       pragma Unreferenced (Old);
+      Def : Iir;
    begin
       --  Create the node.
       case Current_Token is
@@ -2254,6 +2255,22 @@ package body Vhdl.Parse is
         (Subprg, Kind = Iir_Kind_Interface_Function_Declaration, True);
 
       --  TODO: interface_subprogram_default
+      if Current_Token = Tok_Is then
+         --  Skip 'is'.
+         Scan;
+
+         if Current_Token = Tok_Box then
+            Def := Create_Iir (Iir_Kind_Reference_Name);
+            Set_Location (Def);
+
+            --  Skip '<>'.
+            Scan;
+         else
+            Def := Parse_Name;
+         end if;
+
+         Set_Default_Subprogram (Subprg, Def);
+      end if;
 
       return Subprg;
    end Parse_Interface_Subprogram_Declaration;
diff --git a/src/vhdl/vhdl-sem_assocs.adb b/src/vhdl/vhdl-sem_assocs.adb
index 41c93273f..57f3b8815 100644
--- a/src/vhdl/vhdl-sem_assocs.adb
+++ b/src/vhdl/vhdl-sem_assocs.adb
@@ -150,8 +150,9 @@ package body Vhdl.Sem_Assocs is
                Inter := Find_Name_In_Chain
                  (Inter_Chain, Get_Identifier (Formal));
                if Inter /= Null_Iir
-                 and then
-                 Get_Kind (Inter) not in Iir_Kinds_Interface_Object_Declaration
+                 and then Get_Kind (Assoc) /= Iir_Kind_Association_Element_Open
+                 and then (Get_Kind (Inter) not in
+                             Iir_Kinds_Interface_Object_Declaration)
                then
                   Assoc := Rewrite_Non_Object_Association (Assoc, Inter);
                end if;
@@ -1811,58 +1812,37 @@ package body Vhdl.Sem_Assocs is
       return True;
    end Has_Interface_Subprogram_Profile;
 
-   procedure Sem_Association_Subprogram (Assoc : Iir;
-                                         Inter : Iir;
-                                         Finish : Boolean;
-                                         Match : out Compatibility_Level)
+   --  LOC is the location (usually the association, but could be the
+   --  instantiation for unassociated interface).
+   --  RES is set to NULL_IIR in case of error, or the result (in case of
+   --  overload).
+   procedure Sem_Association_Subprogram_Check
+     (Inter : Iir; Res : in out Iir; Loc : Iir)
    is
       Discard : Boolean;
       pragma Unreferenced (Discard);
-      Actual : Iir;
-      Res : Iir;
    begin
-      if not Finish then
-         Sem_Association_Package_Type_Not_Finish (Assoc, Inter, Match);
-         return;
-      end if;
-
-      Match := Fully_Compatible;
-      Sem_Association_Package_Type_Finish (Assoc, Inter);
-      Actual := Get_Actual (Assoc);
-
-      --  LRM08 6.5.7.2 Generic map aspects
-      --  An actual associated with a formal generic subprogram shall be a name
-      --  that denotes a subprogram whose profile conforms to that of the
-      --  formal, or the reserved word OPEN.  The actual, if a predefined
-      --  attribute name that denotes a function, shall be one of the
-      --  predefined attributes 'IMAGE, 'VALUE, 'POS, 'VAL, 'SUCC, 'PREV,
-      --  'LEFTOF, or 'RIGHTOF.
-      Sem_Name (Actual);
-      Res := Get_Named_Entity (Actual);
-
-      if Is_Error (Res) then
-         return;
-      end if;
-
       case Get_Kind (Res) is
          when Iir_Kinds_Subprogram_Declaration
            | Iir_Kinds_Interface_Subprogram_Declaration =>
             if not Has_Interface_Subprogram_Profile (Inter, Res) then
                Error_Msg_Sem
-                 (+Assoc, "profile of %n doesn't match profile of %n",
-                  (+Actual, +Inter));
+                 (+Loc, "profile of %n doesn't match profile of %n",
+                  (+Res, +Inter));
                --  Explain
                Discard := Has_Interface_Subprogram_Profile
-                 (Inter, Res, Get_Location (Assoc));
-               return;
+                 (Inter, Res, Get_Location (Loc));
+               Res := Null_Iir;
             end if;
          when Iir_Kind_Overload_List =>
             declare
+               Orig : Iir;
                Nbr_Errors : Natural;
                List : Iir_List;
                It : List_Iterator;
                El, R : Iir;
             begin
+               Orig := Res;
                Nbr_Errors := 0;
                R := Null_Iir;
                List := Get_Overload_List (Res);
@@ -1875,14 +1855,14 @@ package body Vhdl.Sem_Assocs is
                      else
                         if Nbr_Errors = 0 then
                            Error_Msg_Sem
-                             (+Assoc,
+                             (+Loc,
                               "many possible actual subprogram for %n:",
                               +Inter);
                            Error_Msg_Sem
-                             (+Assoc, " %n declared at %l", (+R, + R));
+                             (+Loc, " %n declared at %l", (+R, + R));
                         else
                            Error_Msg_Sem
-                             (+Assoc, " %n declared at %l", (+El, +El));
+                             (+Loc, " %n declared at %l", (+El, +El));
                         end if;
                         Nbr_Errors := Nbr_Errors + 1;
                      end if;
@@ -1890,33 +1870,99 @@ package body Vhdl.Sem_Assocs is
                   Next (It);
                end loop;
                if Is_Null (R) then
-                  Error_Msg_Sem
-                    (+Assoc, "no matching name for %n", +Inter);
+                  Error_Msg_Sem (+Loc, "no matching name for %n", +Inter);
                   if True then
-                     Error_Msg_Sem
-                       (+Assoc, " these names were incompatible:");
+                     Error_Msg_Sem (+Loc, " these names were incompatible:");
                      It := List_Iterate (List);
                      while Is_Valid (It) loop
                         El := Get_Element (It);
                         Error_Msg_Sem
-                          (+Assoc, " %n declared at %l", (+El, +El));
+                          (+Loc, " %n declared at %l", (+El, +El));
                         Next (It);
                      end loop;
                   end if;
-                  return;
+                  Res := Null_Iir;
                elsif Nbr_Errors > 0 then
-                  return;
+                  Res := Null_Iir;
+               else
+                  Res := R;
                end if;
-               Free_Overload_List (Res);
-               Res := R;
+               Free_Overload_List (Orig);
             end;
          when others =>
-            Error_Kind ("sem_association_subprogram", Res);
+            Report_Start_Group;
+            Error_Msg_Sem
+              (+Loc, "%n must be associated with a subprogram", +Inter);
+            Error_Msg_Sem (+Loc, "found %n defined at %l", (+Res, +Res));
+            Report_End_Group;
+            Res := Null_Iir;
       end case;
+   end Sem_Association_Subprogram_Check;
 
-      Set_Named_Entity (Actual, Res);
-      Vhdl.Xrefs.Xref_Name (Actual);
+   function Sem_Association_Subprogram_Open (Inter : Iir; Loc : Iir)
+                                            return Iir
+   is
+      Res : Iir;
+   begin
+      Res := Sem_Identifier_Name
+        (Get_Identifier (Inter), Loc, False, False);
+      if Is_Error (Res) then
+         return Null_Iir;
+      end if;
+      Sem_Association_Subprogram_Check (Inter, Res, Loc);
+      if Res = Null_Iir then
+         return Null_Iir;
+      end if;
       Sem_Decls.Mark_Subprogram_Used (Res);
+      return Res;
+   end Sem_Association_Subprogram_Open;
+
+   procedure Sem_Association_Subprogram (Assoc : Iir;
+                                         Inter : Iir;
+                                         Finish : Boolean;
+                                         Match : out Compatibility_Level)
+   is
+      Actual : Iir;
+      Res : Iir;
+   begin
+      if not Finish then
+         --  Common code when not finished.
+         Sem_Association_Package_Type_Not_Finish (Assoc, Inter, Match);
+         return;
+      end if;
+
+      Match := Fully_Compatible;
+      Sem_Association_Package_Type_Finish (Assoc, Inter);
+      if Get_Kind (Assoc) = Iir_Kind_Association_Element_Open then
+         Res := Sem_Association_Subprogram_Open (Inter, Assoc);
+         Set_Open_Actual (Assoc, Res);
+      else
+         Actual := Get_Actual (Assoc);
+
+         --  LRM08 6.5.7.2 Generic map aspects
+         --  An actual associated with a formal generic subprogram shall be a
+         --  name that denotes a subprogram whose profile conforms to that of
+         --  the formal, or the reserved word OPEN.  The actual, if a
+         --  predefined attribute name that denotes a function, shall be one
+         --  of the predefined attributes 'IMAGE, 'VALUE, 'POS, 'VAL, 'SUCC,
+         --  'PREV, 'LEFTOF, or 'RIGHTOF.
+         Sem_Name (Actual);
+         Res := Get_Named_Entity (Actual);
+
+         if Is_Error (Res) then
+            return;
+         end if;
+
+         Sem_Association_Subprogram_Check (Inter, Res, Assoc);
+         if Res = Null_Iir then
+            return;
+         end if;
+
+         Set_Named_Entity (Actual, Res);
+         Vhdl.Xrefs.Xref_Name (Actual);
+
+         Sem_Decls.Mark_Subprogram_Used (Res);
+      end if;
    end Sem_Association_Subprogram;
 
    procedure Sem_Association_Terminal
@@ -2296,13 +2342,12 @@ package body Vhdl.Sem_Assocs is
       end case;
    end Sem_Association;
 
-   procedure Sem_Association_Chain
-     (Interface_Chain : Iir;
-      Assoc_Chain: in out Iir;
-      Finish: Boolean;
-      Missing : Missing_Type;
-      Loc : Iir;
-      Match : out Compatibility_Level)
+   procedure Sem_Association_Chain (Interface_Chain : Iir;
+                                    Assoc_Chain: in out Iir;
+                                    Finish: Boolean;
+                                    Missing : Missing_Type;
+                                    Loc : Iir;
+                                    Match : out Compatibility_Level)
    is
       Assoc : Iir;
       Inter : Iir;
@@ -2321,6 +2366,7 @@ package body Vhdl.Sem_Assocs is
       Pos : Integer;
       Formal : Iir;
 
+      Last_Assoc : Iir;
       First_Named_Assoc : Iir;
       Last_Named_Assoc : Iir;
 
@@ -2330,6 +2376,7 @@ package body Vhdl.Sem_Assocs is
       Match := Fully_Compatible;
       First_Named_Assoc := Null_Iir;
       Has_Individual := False;
+      Last_Assoc := Null_Iir;
 
       --  Clear associated type of interface type.
       Inter := Interface_Chain;
@@ -2348,6 +2395,7 @@ package body Vhdl.Sem_Assocs is
       --  First positional associations
       Assoc := Assoc_Chain;
       while Assoc /= Null_Iir loop
+         Last_Assoc := Assoc;
          Formal := Get_Formal (Assoc);
          exit when Formal /= Null_Iir;
 
@@ -2429,6 +2477,7 @@ package body Vhdl.Sem_Assocs is
 
             --  Last assoc to be cleaned up.
             Last_Named_Assoc := Assoc;
+            Last_Assoc := Assoc;
 
             if Finish then
                Sem_Name (Formal);
@@ -2624,6 +2673,7 @@ package body Vhdl.Sem_Assocs is
                   Last_Individual := Null_Iir;
                   if Inter_Matched (Pos) = None then
                      if Get_Kind (Assoc) = Iir_Kind_Association_Element_Open
+                       and then Get_Open_Actual (Assoc) = Null_Iir
                      then
                         Inter_Matched (Pos) := Open;
                      else
@@ -2730,7 +2780,44 @@ package body Vhdl.Sem_Assocs is
       Pos := 0;
       while Inter /= Null_Iir loop
          if Inter_Matched (Pos) <= Open then
-            if Sem_Check_Missing_Association
+            if Get_Kind (Inter) in Iir_Kinds_Interface_Subprogram_Declaration
+              and then Get_Default_Subprogram (Inter) /= Null_Iir
+            then
+               declare
+                  Def : constant Iir := Get_Default_Subprogram (Inter);
+                  Res : Iir;
+                  Ref : Iir;
+               begin
+                  if Finish
+                    and then Get_Kind (Def) = Iir_Kind_Reference_Name
+                  then
+                     --  Resolve now the default subprogram (as we have the
+                     --  context for that).
+                     Res := Sem_Association_Subprogram_Open (Inter, Loc);
+                     if Res /= Null_Iir then
+                        --  Create an artificial open association to keep it.
+                        Assoc :=
+                          Create_Iir (Iir_Kind_Association_Element_Open);
+                        Location_Copy (Assoc, Loc);
+                        Set_Open_Actual (Assoc, Res);
+                        Set_Artificial_Flag (Assoc, True);
+                        Set_Whole_Association_Flag (Assoc, True);
+                        Ref := Create_Iir (Iir_Kind_Reference_Name);
+                        Location_Copy (Ref, Loc);
+                        Set_Named_Entity (Ref, Inter);
+                        Set_Formal (Assoc, Ref);
+
+                        --  Append it.
+                        if Last_Assoc /= Null_Iir then
+                           Set_Chain (Last_Assoc, Assoc);
+                        else
+                           Assoc_Chain := Assoc;
+                        end if;
+                        Last_Assoc := Assoc;
+                     end if;
+                  end if;
+               end;
+            elsif Sem_Check_Missing_Association
               (Inter, Missing, Finish, Inter_Matched (Pos) = Open, Loc)
             then
                Match := Not_Compatible;
@@ -2814,8 +2901,10 @@ package body Vhdl.Sem_Assocs is
             end if;
          when Iir_Kind_Interface_Function_Declaration
             | Iir_Kind_Interface_Procedure_Declaration =>
-            Error_Msg_Sem (+Loc, "%n must be associated", +Inter);
-            Err := True;
+            if Get_Default_Subprogram (Inter) = Null_Iir then
+               Error_Msg_Sem (+Loc, "%n must be associated", +Inter);
+               Err := True;
+            end if;
          when others =>
             Error_Kind ("sem_association_chain", Inter);
       end case;
diff --git a/src/vhdl/vhdl-sem_assocs.ads b/src/vhdl/vhdl-sem_assocs.ads
index fc334d828..509bcf2a1 100644
--- a/src/vhdl/vhdl-sem_assocs.ads
+++ b/src/vhdl/vhdl-sem_assocs.ads
@@ -32,20 +32,19 @@ package Vhdl.Sem_Assocs is
    --  Analyze association chain ASSOC_CHAIN with interfaces from
    --  INTERFACE_CHAIN.
    --  Return the level of compatibility between the two chains in LEVEL.
-   --  If FINISH is true, then ASSOC_CHAIN may be modifies (individual assoc
+   --  If FINISH is true, then ASSOC_CHAIN may be modified (individual assoc
    --  added), and error messages (if any) are displayed.
    --  MISSING control unassociated interfaces.
    -- LOC is the association.
    -- Sem_Actual_Of_Association_Chain must have been called before.
    type Missing_Type is (Missing_Parameter, Missing_Port, Missing_Generic,
                          Missing_Allowed);
-   procedure Sem_Association_Chain
-     (Interface_Chain : Iir;
-      Assoc_Chain: in out Iir;
-      Finish: Boolean;
-      Missing : Missing_Type;
-      Loc : Iir;
-      Match : out Compatibility_Level);
+   procedure Sem_Association_Chain (Interface_Chain : Iir;
+                                    Assoc_Chain: in out Iir;
+                                    Finish: Boolean;
+                                    Missing : Missing_Type;
+                                    Loc : Iir;
+                                    Match : out Compatibility_Level);
 
    --  Check association for expression ACTUAL to interface FORMAL.
    --  ASSOC may be null for operator.
diff --git a/src/vhdl/vhdl-sem_inst.adb b/src/vhdl/vhdl-sem_inst.adb
index f51cd960e..d184aa0ea 100644
--- a/src/vhdl/vhdl-sem_inst.adb
+++ b/src/vhdl/vhdl-sem_inst.adb
@@ -927,7 +927,9 @@ package body Vhdl.Sem_Inst is
 
    --  In the instance, replace references (and inner references) to interface
    --  package declaration to the associated package.
-   procedure Instantiate_Generic_Map (Assoc : Iir; Inter: Iir) is
+   procedure Instantiate_Generic_Map (Assoc : Iir; Inter: Iir)
+   is
+      Assoc_Formal : Iir;
    begin
       --  Replace formal reference to the instance.
       --  Cf Get_association_Interface
@@ -939,7 +941,8 @@ package body Vhdl.Sem_Inst is
             loop
                case Get_Kind (Formal) is
                   when Iir_Kind_Simple_Name
-                    | Iir_Kind_Operator_Symbol =>
+                    | Iir_Kind_Operator_Symbol
+                    | Iir_Kind_Reference_Name =>
                      Set_Named_Entity
                        (Formal, Get_Instance (Get_Named_Entity (Formal)));
                      exit;
@@ -954,16 +957,14 @@ package body Vhdl.Sem_Inst is
          end if;
       end;
 
-      case Get_Kind (Assoc) is
-         when Iir_Kind_Association_Element_By_Expression
-           | Iir_Kind_Association_Element_By_Individual
-           | Iir_Kind_Association_Element_Open =>
+      Assoc_Formal := Get_Association_Interface (Assoc, Inter);
+
+      case Get_Kind (Inter) is
+         when Iir_Kind_Interface_Constant_Declaration =>
             --  If the type of the formal is an interface type also
             --  associated by this map, change the type of the formal
             --  to the associated type.
             declare
-               Assoc_Formal : constant Iir :=
-                 Get_Association_Interface (Assoc, Inter);
                Formal_Type : Iir;
                Formal_Orig : Iir;
             begin
@@ -985,13 +986,13 @@ package body Vhdl.Sem_Inst is
                   end if;
                end if;
             end;
-         when Iir_Kind_Association_Element_Package =>
+         when Iir_Kind_Interface_Package_Declaration =>
+            pragma Assert
+              (Get_Kind (Assoc) = Iir_Kind_Association_Element_Package);
             declare
                Sub_Inst : constant Iir :=
                  Get_Named_Entity (Get_Actual (Assoc));
-               Sub_Pkg_Inter : constant Iir :=
-                 Get_Association_Interface (Assoc, Inter);
-               Sub_Pkg : constant Iir := Get_Origin (Sub_Pkg_Inter);
+               Sub_Pkg : constant Iir := Get_Origin (Assoc_Formal);
             begin
                --  Replace references of interface package to references
                --  to the actual package.
@@ -1001,27 +1002,32 @@ package body Vhdl.Sem_Inst is
                Set_Instance_On_Chain (Get_Declaration_Chain (Sub_Pkg),
                                       Get_Declaration_Chain (Sub_Inst));
             end;
-         when Iir_Kind_Association_Element_Type =>
+         when Iir_Kind_Interface_Type_Declaration =>
+            pragma Assert
+              (Get_Kind (Assoc) = Iir_Kind_Association_Element_Type);
             --  Replace the incomplete interface type by the actual subtype
             --  indication.
             declare
-               Assoc_Inter : constant Iir :=
-                 Get_Association_Interface (Assoc, Inter);
-               Inter_Type_Def : constant Iir := Get_Type (Assoc_Inter);
+               Inter_Type_Def : constant Iir := Get_Type (Assoc_Formal);
                Actual_Type : constant Iir := Get_Actual_Type (Assoc);
             begin
                Set_Instance (Inter_Type_Def, Actual_Type);
             end;
-         when Iir_Kind_Association_Element_Subprogram =>
-            --  Replace the interface subprogram by the subprogram.
-            declare
-               Inter_Subprg : constant Iir :=
-                 Get_Association_Interface (Assoc, Inter);
-               Actual_Subprg : constant Iir :=
-                 Get_Named_Entity (Get_Actual (Assoc));
-            begin
-               Set_Instance (Get_Origin (Inter_Subprg), Actual_Subprg);
-            end;
+         when Iir_Kinds_Interface_Subprogram_Declaration =>
+            if Get_Kind (Assoc) = Iir_Kind_Association_Element_Open then
+               Set_Instance (Get_Origin (Assoc_Formal),
+                             Get_Open_Actual (Assoc));
+            else
+               pragma Assert
+                 (Get_Kind (Assoc) = Iir_Kind_Association_Element_Subprogram);
+               --  Replace the interface subprogram by the subprogram.
+               declare
+                  Actual_Subprg : constant Iir :=
+                    Get_Named_Entity (Get_Actual (Assoc));
+               begin
+                  Set_Instance (Get_Origin (Assoc_Formal), Actual_Subprg);
+               end;
+            end if;
          when others =>
             Error_Kind ("instantiate_generic_map", Assoc);
       end case;
@@ -1167,8 +1173,8 @@ package body Vhdl.Sem_Inst is
          Inst_El := Get_Generic_Map_Aspect_Chain (Inst);
          Inter_El := Get_Generic_Chain (Inst);
          while Is_Valid (Inst_El) loop
-            case Get_Kind (Inst_El) is
-               when Iir_Kind_Association_Element_Type =>
+            case Get_Kind (Inter_El) is
+               when Iir_Kind_Interface_Type_Declaration =>
                   Inter := Get_Association_Interface (Inst_El, Inter_El);
                   Set_Instance (Get_Type (Get_Origin (Inter)),
                                 Get_Actual_Type (Inst_El));
@@ -1189,14 +1195,18 @@ package body Vhdl.Sem_Inst is
                      end loop;
                   end;
 
-               when Iir_Kind_Association_Element_Subprogram =>
+               when Iir_Kinds_Interface_Subprogram_Declaration =>
                   Inter := Get_Association_Interface (Inst_El, Inter_El);
-                  Set_Instance (Get_Origin (Inter),
-                                Get_Named_Entity (Get_Actual (Inst_El)));
+                  if Get_Kind (Inst_El) = Iir_Kind_Association_Element_Open
+                  then
+                     Set_Instance (Get_Origin (Inter),
+                                   Get_Open_Actual (Inst_El));
+                  else
+                     Set_Instance (Get_Origin (Inter),
+                                   Get_Named_Entity (Get_Actual (Inst_El)));
+                  end if;
 
-               when Iir_Kind_Association_Element_By_Expression
-                 | Iir_Kind_Association_Element_By_Individual
-                 | Iir_Kind_Association_Element_Open =>
+               when Iir_Kind_Interface_Constant_Declaration =>
                   null;
                when others =>
                   --  TODO.
diff --git a/src/vhdl/vhdl-sem_names.adb b/src/vhdl/vhdl-sem_names.adb
index 438945faa..b6ed45227 100644
--- a/src/vhdl/vhdl-sem_names.adb
+++ b/src/vhdl/vhdl-sem_names.adb
@@ -15,15 +15,15 @@
 --  along with this program.  If not, see <gnu.org/licenses>.
 with Flags; use Flags;
 with Name_Table;
+with Std_Names;
 with Libraries;
+with Errorout; use Errorout;
+
 with Vhdl.Evaluation; use Vhdl.Evaluation;
 with Vhdl.Utils; use Vhdl.Utils;
-with Errorout; use Errorout;
 with Vhdl.Errors; use Vhdl.Errors;
 with Vhdl.Std_Package; use Vhdl.Std_Package;
-with Types; use Types;
 with Vhdl.Nodes_Utils; use Vhdl.Nodes_Utils;
-with Std_Names;
 with Vhdl.Sem;
 with Vhdl.Sem_Lib; use Vhdl.Sem_Lib;
 with Vhdl.Sem_Scopes; use Vhdl.Sem_Scopes;
@@ -2089,19 +2089,11 @@ package body Vhdl.Sem_Names is
       return Finish_Sem_Name_1 (Name, Get_Named_Entity (Name));
    end Finish_Sem_Name;
 
-   --  LRM93 6.2
-   --  The evaluation of a simple name has no other effect than to determine
-   --  the named entity denoted by the name.
-   --
-   --  NAME may be a simple name, a strig literal or a character literal.
-   --  GHDL: set interpretation of NAME (possibly an overload list) or
-   --  error_mark for unknown names.
-   --  If SOFT is TRUE, then no error message is reported in case of failure.
-   procedure Sem_Simple_Name (Name : Iir; Keep_Alias : Boolean; Soft : Boolean)
+   function Sem_Identifier_Name
+     (Id : Name_Id; Loc : Iir; Keep_Alias : Boolean; Soft : Boolean) return Iir
    is
-      Id : constant Name_Id := Get_Identifier (Name);
       Interpretation: Name_Interpretation_Type;
-      Res: Iir;
+      Res : Iir;
       Res_List : Iir_List;
       Res_It : List_Iterator;
       N : Natural;
@@ -2116,9 +2108,9 @@ package body Vhdl.Sem_Names is
               and then Is_Conflict_Declaration (Interpretation)
             then
                Error_Msg_Sem
-                 (+Name, "no declaration for %i (due to conflicts)", +Name);
+                 (+Loc, "no declaration for %i (due to conflicts)", +Id);
             else
-               Error_Msg_Sem (+Name, "no declaration for %i", +Name);
+               Error_Msg_Sem (+Loc, "no declaration for %i", +Id);
             end if;
          end if;
          Res := Error_Mark;
@@ -2130,7 +2122,7 @@ package body Vhdl.Sem_Names is
          --  For a design unit, return the library unit
          if Get_Kind (Res) = Iir_Kind_Design_Unit then
             --  FIXME: should replace interpretation ?
-            Load_Design_Unit (Res, Name);
+            Load_Design_Unit (Res, Loc);
             Sem.Add_Dependence (Res);
             Res := Get_Library_Unit (Res);
          end if;
@@ -2144,7 +2136,7 @@ package body Vhdl.Sem_Names is
                Res := Get_Declaration (Get_Under_Interpretation (Id));
             else
                if not Soft then
-                  Error_Msg_Sem (+Name, "%n is not visible here", +Res);
+                  Error_Msg_Sem (+Loc, "%n is not visible here", +Res);
                end if;
                --  Even if a named entity was found, return an error_mark.
                --  Indeed, the named entity found is certainly the one being
@@ -2189,7 +2181,23 @@ package body Vhdl.Sem_Names is
 
          Res := Create_Overload_List (Res_List);
       end if;
+      return Res;
+   end Sem_Identifier_Name;
 
+   --  LRM93 6.2
+   --  The evaluation of a simple name has no other effect than to determine
+   --  the named entity denoted by the name.
+   --
+   --  NAME may be a simple name, a strig literal or a character literal.
+   --  GHDL: set interpretation of NAME (possibly an overload list) or
+   --  error_mark for unknown names.
+   --  If SOFT is TRUE, then no error message is reported in case of failure.
+   procedure Sem_Simple_Name (Name : Iir; Keep_Alias : Boolean; Soft : Boolean)
+   is
+      Id : constant Name_Id := Get_Identifier (Name);
+      Res : Iir;
+   begin
+      Res := Sem_Identifier_Name (Id, Name, Keep_Alias, Soft);
       Set_Named_Entity (Name, Res);
    end Sem_Simple_Name;
 
diff --git a/src/vhdl/vhdl-sem_names.ads b/src/vhdl/vhdl-sem_names.ads
index 8c8abf488..2ed16a001 100644
--- a/src/vhdl/vhdl-sem_names.ads
+++ b/src/vhdl/vhdl-sem_names.ads
@@ -13,6 +13,7 @@
 --
 --  You should have received a copy of the GNU General Public License
 --  along with this program.  If not, see <gnu.org/licenses>.
+with Types; use Types;
 with Vhdl.Nodes; use Vhdl.Nodes;
 
 package Vhdl.Sem_Names is
@@ -73,6 +74,20 @@ package Vhdl.Sem_Names is
    --  To be used only for names (weakly) analyzed by sem_name_soft.
    procedure Sem_Name_Clean (Name : Iir);
 
+   --  Return an interpretation for identifier ID.
+   --  Used mostly by Sem_Simple_Name but also for unassociated interface
+   --  subprogram whose default is <>.
+   --  Do not follow aliases is KEEP_ALIAS is true (used for attribute
+   --  specification),
+   --  do not report error if SOFT is true (used for associations of
+   --  overloaded names).
+   --
+   --  Returns either the interpretation, an overload list or a error_mark.
+   function Sem_Identifier_Name (Id : Name_Id;
+                                 Loc : Iir;
+                                 Keep_Alias : Boolean;
+                                 Soft : Boolean) return Iir;
+
    --  If NAME is a selected name whose prefix is a protected variable, set
    --  method_object of CALL.
    procedure Name_To_Method_Object (Call : Iir; Name : Iir);
diff --git a/src/vhdl/vhdl-utils.adb b/src/vhdl/vhdl-utils.adb
index 729e7352b..8c94903a0 100644
--- a/src/vhdl/vhdl-utils.adb
+++ b/src/vhdl/vhdl-utils.adb
@@ -569,6 +569,7 @@ package body Vhdl.Utils is
       loop
          case Get_Kind (El) is
             when Iir_Kind_Simple_Name
+              | Iir_Kind_Reference_Name
               | Iir_Kind_Operator_Symbol =>
                --  Operator is for subprogram interfaces.
                return Get_Named_Entity (El);
@@ -630,6 +631,7 @@ package body Vhdl.Utils is
          --  Strip denoting name
          case Get_Kind (Formal) is
             when Iir_Kind_Simple_Name
+              | Iir_Kind_Reference_Name
               | Iir_Kind_Operator_Symbol =>
                return Get_Named_Entity (Formal);
             when Iir_Kinds_Interface_Declaration =>