[Bug ada/114636] New: Actual does not match formal in generic instantiation

[Bug ada/114636] New: Actual does not match formal in generic instantiation

[simon at pushface dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114636

            Bug ID: 114636
           Summary: Actual does not match formal in generic instantiation
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: simon at pushface dot org
                CC: dkm at gcc dot gnu.org
  Target Milestone: ---

Created attachment 57899
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57899&action=edit
example.adb

Compiler can’t match an actual type with a formal.
This appears to have been present from GCC 8.2, and is still present.
Could it be related to PR24480?

$ gnatmake -gnatl example.adb
gcc -c -gnatl example.adb

GNAT 13.2.1
Copyright 1992-2023, Free Software Foundation, Inc.

Compiling: example.adb
Source file time stamp: 2024-04-08 09:57:34
Compiled at: 2024-04-08 11:09:37

     1. procedure Example is
     2.    generic
     3.       type Terminals is (<>);
     4.       type Nonterminals is (<>);
     5.    package Types is
     6.       type Action is record
     7.          data : Integer;
     8.       end record;
     9.    end Types;
    10.
    11.    generic
    12.       type States is (<>);
    13.       type Input_T is (<>);
    14.       type Action_T is private;
    15.    package FSM is
    16.    end FSM;
    17.
    18.    generic
    19.       with package Typs is new Types (<>);
    20.       with package SMs is new FSM
    21.         (States => <>, Input_T => Typs.Terminals, Action_T =>
Typs.Action);
    22.    package Gen is
    23.    end Gen;
    24.
    25.    package Typs is new Types (Natural, Integer);
    26.    package SMs is new FSM (Integer, Natural, Typs.Action);
    27.    package Generator is new Gen (Typs, SMs);
                                               |
        >>> error: actual for "Action_T" in actual instance does not match
formal

    28. begin
    29.    null;
    30. end Example;

 30 lines: 1 error

[Bug ada/114636] actual does not match formal in instantiation with formal package

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114636

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Actual does not match       |actual does not match
                   |formal in generic           |formal in instantiation
                   |instantiation               |with formal package
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-04-20
                 CC|                            |ebotcazou at gcc dot gnu.org

--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
This comes from the formal discrete types and has probably never worked.

[Bug ada/114636] actual does not match formal in instantiation with formal package

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114636

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
This appears to be sufficient:

diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb
index e7b759c4e88..c06377ab4c9 100644
--- a/gcc/ada/sem_ch12.adb
+++ b/gcc/ada/sem_ch12.adb
@@ -6696,8 +6696,12 @@ package body Sem_Ch12 is
          then
             --  If the formal is a tagged type the corresponding class-wide
             --  type has been generated as well, and it must be skipped.
+            --  Likewise, for a formal discrete type, the base type has been
+            --  generated as well (see Analyze_Formal_Discrete_Type).

-            if Is_Type (E2) and then Is_Tagged_Type (E2) then
+            if Is_Type (E2)
+              and then (Is_Tagged_Type (E2) or else Is_Enumeration_Type (E2))
+            then
                Next_Entity (E2);
             end if;

[Bug ada/114636] actual does not match formal in instantiation with formal package

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114636

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |ebotcazou at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #3 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
I'll test the above fixlet.