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From: Pierre-Marie de Rodat <derodat@adacore.com>
To: gcc-patches@gcc.gnu.org
Cc: Justin Squirek <squirek@adacore.com>
Subject: [Ada] Compiler hangs on evaluation of use-clause within package context
Date: Fri, 29 Sep 2017 13:24:00 -0000	[thread overview]
Message-ID: <20170929132359.GA145182@adacore.com> (raw)

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Due to the installation order of packages within a context clause it is
possible to create circularities within the Prev_Use_Clause clain. This patch
corrects this issue by identifying this case through the use of an extra check.

Tested on x86_64-pc-linux-gnu, committed on trunk

2017-09-29  Justin Squirek  <squirek@adacore.com>

	* sem_ch8.adb (Analyze_Use_Package): Add sanity check to avoid
	circularities in the use-clause chain.


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Index: sem_ch8.adb
===================================================================
--- sem_ch8.adb	(revision 253285)
+++ sem_ch8.adb	(working copy)
@@ -3782,9 +3782,10 @@
       --  before setting its previous use clause.
 
       if Ekind (Pack) = E_Package
-         and then Present (Current_Use_Clause (Pack))
-         and then Current_Use_Clause (Pack) /= N
-         and then No (Prev_Use_Clause (N))
+        and then Present (Current_Use_Clause (Pack))
+        and then Current_Use_Clause (Pack) /= N
+        and then No (Prev_Use_Clause (N))
+        and then Prev_Use_Clause (Current_Use_Clause (Pack)) /= N
       then
          Set_Prev_Use_Clause (N, Current_Use_Clause (Pack));
       end if;

                 reply	other threads:[~2017-09-29 13:24 UTC|newest]

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