[gcc r13-1626] [Ada] Warn on unset objects in packages with no bodies

[gcc r13-1626] [Ada] Warn on unset objects in packages with no bodies

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:a8d17a88a52d2f773423adb55399d23ed5ea03c8

commit r13-1626-ga8d17a88a52d2f773423adb55399d23ed5ea03c8
Author: Piotr Trojanek <trojanek@adacore.com>
Date:   Tue Jun 21 10:17:57 2022 +0200

    [Ada] Warn on unset objects in packages with no bodies
    
    Fix an inconsistency, where GNAT was warning about references to unset
    objects inside generic packages with no bodies but not inside ordinary
    packages with no bodies.
    
    gcc/ada/
    
            * sem_ch7.adb (Analyze_Package_Declaration): Check references to
            unset objects.
    
    gcc/testsuite/
    
            * gnat.dg/specs/discr5.ads: Expect new warnings.
            * gnat.dg/specs/empty_variants.ads: Likewise.
            * gnat.dg/specs/pack13.ads: Likewise.

Diff:
---
 gcc/ada/sem_ch7.adb                            | 7 +++++++
 gcc/testsuite/gnat.dg/specs/discr5.ads         | 5 +++--
 gcc/testsuite/gnat.dg/specs/empty_variants.ads | 4 ++--
 gcc/testsuite/gnat.dg/specs/pack13.ads         | 2 +-
 4 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/gcc/ada/sem_ch7.adb b/gcc/ada/sem_ch7.adb
index 31c04ad077d..5c347bd8b4f 100644
--- a/gcc/ada/sem_ch7.adb
+++ b/gcc/ada/sem_ch7.adb
@@ -1253,6 +1253,13 @@ package body Sem_Ch7 is
               (Context      => N,
                Is_Main_Unit => Parent (N) = Cunit (Main_Unit));
          end if;
+
+         --  Warn about references to unset objects, which is straightforward
+         --  for packages with no bodies. For packages with bodies this is more
+         --  complicated, because some of the objects might be set between spec
+         --  and body elaboration, in nested or child packages, etc.
+
+         Check_References (Id);
       end if;
 
       --  Set Body_Required indication on the compilation unit node
diff --git a/gcc/testsuite/gnat.dg/specs/discr5.ads b/gcc/testsuite/gnat.dg/specs/discr5.ads
index c265723ec47..79c234a487b 100644
--- a/gcc/testsuite/gnat.dg/specs/discr5.ads
+++ b/gcc/testsuite/gnat.dg/specs/discr5.ads
@@ -22,7 +22,7 @@ package Discr5 is
    subtype Rt is R(True);
    subtype Rf is R(False);
 
-   type R1 (D1 : Boolean) is new R (X) with record
+   type R1 (D1 : Boolean) is new R (X) with record -- { dg-warning "\"X\" may be referenced before it has a value" }
       FF : Float;
       case D1 is
          when True =>
@@ -38,7 +38,7 @@ package Discr5 is
    subtype R1t is R1 (True);
    subtype R1f is R1 (False);
 
-   type R2 (D2 : Boolean) is new R1 (Y) with record
+   type R2 (D2 : Boolean) is new R1 (Y) with record -- { dg-warning "\"Y\" may be referenced before it has a value" }
       FFF: System.Address;
       case D2 is
          when True =>
@@ -55,3 +55,4 @@ package Discr5 is
    subtype R2f is R2 (False);
 
 end Discr5;
+
diff --git a/gcc/testsuite/gnat.dg/specs/empty_variants.ads b/gcc/testsuite/gnat.dg/specs/empty_variants.ads
index 079b64ac812..9b0cdadeae8 100644
--- a/gcc/testsuite/gnat.dg/specs/empty_variants.ads
+++ b/gcc/testsuite/gnat.dg/specs/empty_variants.ads
@@ -1,5 +1,4 @@
 --  { dg-do compile }
---  { dg-options "-gnatdF" }
 
 package Empty_Variants is
    
@@ -23,10 +22,11 @@ package Empty_Variants is
    
    R : Rec;
    
-   I : Integer := R.I;
+   I : Integer := R.I; -- { dg-warning "\"R\.I\" may be referenced before it has a value" }
    J : Integer := R.J;
    K : Integer := R.K;
    L : Integer := R.L;
    M : Integer := R.L;
 
 end Empty_Variants;
+
diff --git a/gcc/testsuite/gnat.dg/specs/pack13.ads b/gcc/testsuite/gnat.dg/specs/pack13.ads
index 4594ab7ca03..86145500ca0 100644
--- a/gcc/testsuite/gnat.dg/specs/pack13.ads
+++ b/gcc/testsuite/gnat.dg/specs/pack13.ads
@@ -20,6 +20,6 @@ package Pack13 is
 
   A : Arr;
 
-  package My_G is new G (Boolean, A(True).B);
+  package My_G is new G (Boolean, A(True).B); -- { dg-warning "\"A\" may be referenced before it has a value" }
 
 end Pack13;