[gcc r13-239] [Ada] Check declare and qualified expressions for unset references

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:3a978538036cd43d629c7b003c5ee6c8b3bf2c98

commit r13-239-g3a978538036cd43d629c7b003c5ee6c8b3bf2c98
Author: Piotr Trojanek <trojanek@adacore.com>
Date:   Sat Jan 22 16:32:57 2022 +0100

    [Ada] Check declare and qualified expressions for unset references
    
    Detection of references to unset (uninitialized) objects requires calls
    to Check_Unset_Reference on every subexpression of a composite statement
    and expression. For declare and qualified expressions this was done only
    when they occurred within another composite statement/expression.
    
    gcc/ada/
    
            * sem_res.adb (Resolve_Declare_Expression): Check expression for
            references to unset objects.
            (Resolve_Qualified_Expression): Likewise.
            * sem_warn.adb (Check_Unset_Reference): Remove handling of
            declare and qualified expressions; clarify comment for type
            conversions.

Diff:
---
 gcc/ada/sem_res.adb  |  2 ++
 gcc/ada/sem_warn.adb | 10 ++++------
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
index 7d30f150e3d..5a57d62faae 100644
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -7673,6 +7673,7 @@ package body Sem_Res is
       end if;
 
       Resolve (Expr, Typ);
+      Check_Unset_Reference (Expr);
    end Resolve_Declare_Expression;
 
    -----------------------------------------
@@ -10586,6 +10587,7 @@ package body Sem_Res is
 
    begin
       Resolve (Expr, Target_Typ);
+      Check_Unset_Reference (Expr);
 
       --  A qualified expression requires an exact match of the type, class-
       --  wide matching is not allowed. However, if the qualifying type is
diff --git a/gcc/ada/sem_warn.adb b/gcc/ada/sem_warn.adb
index e02f6e04947..8ca5c76a075 100644
--- a/gcc/ada/sem_warn.adb
+++ b/gcc/ada/sem_warn.adb
@@ -2244,13 +2244,11 @@ package body Sem_Warn is
                Check_Unset_Reference (Pref);
             end;
 
-         --  For type conversions, qualifications, or expressions with actions,
-         --  examine the expression.
+         --  Type conversions can appear in assignment statements both
+         --  as variable names and as expressions. We examine their own
+         --  expressions only when processing their parent node.
 
-         when N_Expression_With_Actions
-            | N_Qualified_Expression
-            | N_Type_Conversion
-         =>
+         when N_Type_Conversion =>
             Check_Unset_Reference (Expression (N));
 
          --  For explicit dereference, always check prefix, which will generate