From 2a38c2330fd498dd929fedff32023050e223c039 Mon Sep 17 00:00:00 2001
From: Bob Duff <duff@adacore.com>
Date: Mon, 9 Dec 2024 12:20:34 -0500
Subject: [PATCH] ada: null procedure cannot be used as compilation unit
This patch gives a syntax error if a null procedure is used as
a compilation unit. The error was already given during semantic
analysis; now it is given in the parser, which is more convenient
for other tools like gprbuild, because the -gnats switch now
gives the error.
Note that the old message "null procedure cannot be declared at library
level" was wrong; "library level" is not the same thing as "is a library
unit".
gcc/ada/ChangeLog:
* par-ch10.adb (P_Compilation_Unit): Give an error for "is null".
* sem_ch10.adb (Analyze_Subunit): Remove check for "is null"
as a subunit.
* sem_ch6.adb (Analyze_Subprogram_Declaration):
Remove check for "is null" as a library unit.
---
gcc/ada/par-ch10.adb | 9 +++++++++
gcc/ada/sem_ch10.adb | 16 +++++-----------
gcc/ada/sem_ch6.adb | 8 --------
3 files changed, 14 insertions(+), 19 deletions(-)
diff --git a/gcc/ada/par-ch10.adb b/gcc/ada/par-ch10.adb
index 7317b75a1a5d..576614f09019 100644
--- a/gcc/ada/par-ch10.adb
+++ b/gcc/ada/par-ch10.adb
@@ -532,6 +532,15 @@ package body Ch10 is
Unit_Node := Specification (Unit_Node);
end if;
+ -- Disallow null procedures as library units and subunits
+
+ if Nkind (Unit_Node) = N_Procedure_Specification
+ and then Null_Present (Unit_Node)
+ then
+ Error_Msg_N
+ ("null procedure cannot be used as compilation unit", Unit_Node);
+ end if;
+
if Nkind (Unit_Node) in N_Task_Body
| N_Protected_Body
| N_Task_Type_Declaration
diff --git a/gcc/ada/sem_ch10.adb b/gcc/ada/sem_ch10.adb
index d0aaa6c10503..fee6583d5359 100644
--- a/gcc/ada/sem_ch10.adb
+++ b/gcc/ada/sem_ch10.adb
@@ -2820,20 +2820,14 @@ package body Sem_Ch10 is
Install_Elaboration_Model (Par_Unit);
- -- The syntax rules require a proper body for a subprogram subunit
+ -- The syntax rules require a proper body for a subprogram subunit.
+ -- Note that we already checked for "is null" in the parser.
if Nkind (Proper_Body (Sinfo.Nodes.Unit (N))) = N_Subprogram_Declaration
then
- if Null_Present (Specification (Proper_Body (Sinfo.Nodes.Unit (N))))
- then
- Error_Msg_N
- ("null procedure not allowed as subunit",
- Proper_Body (Unit (N)));
- else
- Error_Msg_N
- ("subprogram declaration not allowed as subunit",
- Defining_Unit_Name (Specification (Proper_Body (Unit (N)))));
- end if;
+ Error_Msg_N
+ ("subprogram declaration not allowed as subunit",
+ Defining_Unit_Name (Specification (Proper_Body (Unit (N)))));
end if;
Analyze (Proper_Body (Unit (N)));
diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
index 2e619d89444a..1e91bf810ef1 100644
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -5156,14 +5156,6 @@ package body Sem_Ch6 is
if Nkind (Parent (N)) = N_Compilation_Unit then
Set_Body_Required (Parent (N), True);
-
- if Ada_Version >= Ada_2005
- and then Nkind (Specification (N)) = N_Procedure_Specification
- and then Null_Present (Specification (N))
- then
- Error_Msg_N
- ("null procedure cannot be declared at library level", N);
- end if;
end if;
Generate_Reference_To_Formals (Designator);
--
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