{"id":812742,"url":"http://patchwork.ozlabs.org/api/patches/812742/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/20170912091237.GA64499@adacore.com/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170912091237.GA64499@adacore.com>","list_archive_url":null,"date":"2017-09-12T09:12:37","name":"[Ada] Dynamically tagged expr of expr function is illegal","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"8f2efea051f557578de99f4ac72da577384c0fc7","submitter":{"id":4418,"url":"http://patchwork.ozlabs.org/api/people/4418/?format=json","name":"Arnaud Charlet","email":"charlet@adacore.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/20170912091237.GA64499@adacore.com/mbox/","series":[{"id":2644,"url":"http://patchwork.ozlabs.org/api/series/2644/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=2644","date":"2017-09-12T09:12:37","name":"[Ada] Dynamically tagged expr of expr function is illegal","version":1,"mbox":"http://patchwork.ozlabs.org/series/2644/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/812742/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/812742/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":["patchwork-incoming@bilbo.ozlabs.org","mailing list gcc-patches@gcc.gnu.org"],"Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=gcc.gnu.org\n\t(client-ip=209.132.180.131; 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run by ezmlm","Precedence":"bulk","List-Id":"","List-Unsubscribe":"","List-Archive":"","List-Post":"","List-Help":"","Sender":"gcc-patches-owner@gcc.gnu.org","X-Virus-Found":"No","X-Spam-SWARE-Status":"No, score=-10.5 required=5.0 tests=AWL, BAYES_00,\n\tGIT_PATCH_2, GIT_PATCH_3, KAM_ASCII_DIVIDERS,\n\tRCVD_IN_DNSWL_NONE,\n\tSPF_PASS autolearn=ham version=3.3.2 spammy=","X-HELO":"rock.gnat.com","Date":"Tue, 12 Sep 2017 05:12:37 -0400","From":"Arnaud Charlet ","To":"gcc-patches@gcc.gnu.org","Cc":"Bob Duff ","Subject":"[Ada] Dynamically tagged expr of expr function is illegal","Message-ID":"<20170912091237.GA64499@adacore.com>","MIME-Version":"1.0","Content-Type":"multipart/mixed; boundary=\"sm4nu43k4a2Rpi4c\"","Content-Disposition":"inline","User-Agent":"Mutt/1.5.23 (2014-03-12)"},"content":"It is illegal to return a dynamically tagged expression\nfrom an expression function that returns a specific type. See\nRM-3.9.2(9). This patch fixes a bug that caused the compiler\nto fail to detect this illegality.\n\nTested on x86_64-pc-linux-gnu, committed on trunk\n\n2017-09-12 Bob Duff \n\n\t* sem_ch6.adb (Analyze_Expression_Function): Call\n\tCheck_Dynamically_Tagged_Expression.\n\t* sem_util.adb (Check_Dynamically_Tagged_Expression): Remove\n\t\"and then Is_Tagged_Type (Typ)\" because there is an earlier\n\t\"Assert (Is_Tagged_Type (Typ))\".","diff":"Index: sem_util.adb\n===================================================================\n--- sem_util.adb\t(revision 251998)\n+++ sem_util.adb\t(working copy)\n@@ -2022,7 +2022,6 @@\n or else In_Generic_Actual (Expr))\n and then (Is_Class_Wide_Type (Etype (Expr))\n or else Is_Dynamically_Tagged (Expr))\n- and then Is_Tagged_Type (Typ)\n and then not Is_Class_Wide_Type (Typ)\n then\n Error_Msg_N (\"dynamically tagged expression not allowed!\", Expr);\nIndex: sem_ch6.adb\n===================================================================\n--- sem_ch6.adb\t(revision 251998)\n+++ sem_ch6.adb\t(working copy)\n@@ -741,6 +741,21 @@\n end;\n end if;\n \n+ -- Check incorrect use of dynamically tagged expression. This doesn't\n+ -- fall out automatically when analyzing the generated function body,\n+ -- because Check_Dynamically_Tagged_Expression deliberately ignores\n+ -- nodes that don't come from source.\n+\n+ if Present (Def_Id)\n+ and then Nkind (Def_Id) in N_Has_Etype\n+ and then Is_Tagged_Type (Etype (Def_Id))\n+ then\n+ Check_Dynamically_Tagged_Expression\n+ (Expr => Expr,\n+ Typ => Etype (Def_Id),\n+ Related_Nod => Original_Node (N));\n+ end if;\n+\n -- If the return expression is a static constant, we suppress warning\n -- messages on unused formals, which in most cases will be noise.\n \n","prefixes":["Ada"]}