[Ada] Missing diagnostic of categorization dependency

This patch modifies the analysis of subprogram bodies to catch a case where a
pure subprogram body unit depends on non-pure units.

2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* sem_ch6.adb (Analyze_Subprogram_Body_Helper): Check the
	categorization of a subprogram body which does not complete a previous
	declaration.

gcc/testsuite/

	* gnat.dg/pure_subp_body.adb, gnat.dg/pure_subp_body_pkg.ads: New
	testcase.

From-SVN: r256516

gcc/ada/ChangeLog

 2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>
 
+	* sem_ch6.adb (Analyze_Subprogram_Body_Helper): Check the
+	categorization of a subprogram body which does not complete a previous
+	declaration.
+
+2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>
+
 	* sem_ch10.adb (Check_Private_Child_Unit): Ensure that the enclosing
 	scope of package Ada is Standard.
 

gcc/ada/sem_ch6.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2017, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2018, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -4463,6 +4463,12 @@ package body Sem_Ch6 is
             Set_First_Entity (Spec_Id, Empty);
             Set_Last_Entity  (Spec_Id, Empty);
          end if;
+
+      --  Otherwise the body does not complete a previous declaration. Check
+      --  the categorization of the body against the units it withs.
+
+      else
+         Validate_Categorization_Dependency (N, Body_Id);
       end if;
 
       Check_Missing_Return;

gcc/testsuite/ChangeLog

+2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>
+
+	* gnat.dg/pure_subp_body.adb, gnat.dg/pure_subp_body_pkg.ads: New
+	testcase.
+
 2018-01-11  Bob Duff  <duff@adacore.com>
 
 	* gnat.dg/protected_null.adb: New testcase.

gcc/testsuite/gnat.dg/pure_subp_body.adb

+--  { dg-do compile }
+
+with Pure_Subp_Body_Pkg;
+
+procedure Pure_Subp_Body with Pure is
+begin
+    null;
+end Pure_Subp_Body;
+
+--  cannot depend on "Pure_Subp_Body_Pkg" (wrong categorization)
+--  { dg-error "cannot depend on \"Pure_Subp_Body_Pkg\" \\(wrong categorization\\)" "" { target *-*-* } 3 }
+--  { dg-error "pure unit cannot depend on non-pure unit" "non-pure unit" { target *-*-* } 3 }

gcc/testsuite/gnat.dg/pure_subp_body_pkg.ads

+package Pure_Subp_Body_Pkg is
+end Pure_Subp_Body_Pkg;