From 500b21ddb7ff3546e9b7f100b7414347661c7fb9 Mon Sep 17 00:00:00 2001 From: Ed Schonberg Date: Mon, 28 May 2018 08:53:06 +0000 Subject: [PATCH] [Ada] Warning on recursive call within postcondition This patch adds a warning to a function call that appears within a postcondition for said function. This may mean an omission of an attribute reference 'Result, and may lead to an infinite loop on a call to that function. Compiling post_error.ads must yield: post_error.ads:3:11: warning: postcondition does not mention function result post_error.ads:3:19: warning: call to "Foo" within its postcondition will lead to infinite recursion ---- package Post_Error is function Foo (A : out Integer) return Integer with Post => Foo (A) /= 0; pragma Import (C, Foo); end Post_Error; 2018-05-28 Ed Schonberg gcc/ada/ * sem_util.adb (Is_Function_Result): Add a warning if a postcondition includes a call to function to which it applies. This may mean an omission of an attribute reference 'Result, in particular if the function is pqrameterless. From-SVN: r260818 --- gcc/ada/ChangeLog | 7 +++++++ gcc/ada/sem_util.adb | 11 +++++++++++ 2 files changed, 18 insertions(+) diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 10b2c21fa38..6f08ad2efff 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,10 @@ +2018-05-28 Ed Schonberg + + * sem_util.adb (Is_Function_Result): Add a warning if a postcondition + includes a call to function to which it applies. This may mean an + omission of an attribute reference 'Result, in particular if the + function is pqrameterless. + 2018-05-28 Justin Squirek * sem_ch8.adb (Find_Expanded_Name): Add extra guard to make sure the diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb index 033903c09ea..facacbea213 100644 --- a/gcc/ada/sem_util.adb +++ b/gcc/ada/sem_util.adb @@ -3880,6 +3880,17 @@ package body Sem_Util is Result_Seen := True; return Abandon; + -- Warn on infinite recursion if call is to current function. + + elsif Nkind (N) = N_Function_Call + and then Is_Entity_Name (Name (N)) + and then Entity (Name (N)) = Subp_Id + and then not Is_Potentially_Unevaluated (N) + then + Error_Msg_NE ("call to & within its postcondition " + & "will lead to infinite recursion?", N, Subp_Id); + return OK; + -- Continue the traversal else -- 2.30.2