From f95fb9d019147b2af0c8107d6c6a6e2b6034d9fe Mon Sep 17 00:00:00 2001 From: Ed Schonberg Date: Mon, 9 Mar 2020 16:36:55 -0400 Subject: [PATCH] [Ada] Additional warnings on overlapping actuals of composite types 2020-06-10 Ed Schonberg gcc/ada/ * sem_warn.adb (Warn_On_Overlapping_Actuals): Add a warning when two actuals in a call overlap, both are composite types that may be passed by reference, and only one of them is writable. --- gcc/ada/sem_warn.adb | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/gcc/ada/sem_warn.adb b/gcc/ada/sem_warn.adb index b84e82e989a..a3195a19369 100644 --- a/gcc/ada/sem_warn.adb +++ b/gcc/ada/sem_warn.adb @@ -3742,10 +3742,26 @@ package body Sem_Warn is -- If appropriate warning switch is set, we also report warnings on -- overlapping parameters that are record types or array types. + -- It is also worthwhile to warn on overlaps of composite objects when + -- only one of the formals is (in)-out. Note that the RM rule above is + -- a legality rule. We choose to implement this check as a warning to + -- avoid major incompatibilities with legacy code. We exclude internal + -- sources from the warning, because subprograms in Container libraries + -- would be affected by the warning. + + -- Note also that the rule in 6.4.1 (6.17/3), introduced by AI12-0324, + -- is potentially more expensive to verify, and is not yet implemented. + + if Is_Internal_Unit (Current_Sem_Unit) then + return; + end if; + Form1 := First_Formal (Subp); Act1 := First_Actual (N); while Present (Form1) and then Present (Act1) loop - if Is_Covered_Formal (Form1) then + if Is_Covered_Formal (Form1) + or else not Is_Elementary_Type (Etype (Act1)) + then Form2 := First_Formal (Subp); Act2 := First_Actual (N); while Present (Form2) and then Present (Act2) loop -- 2.30.2