[Ada] No error on missing enclosing parentheses in Expression Function

This patch fixes an issue whereby an expression within an expression
function declaration or completion without proper parenthesization is
incorrectly accepted by the compiler.

2018-01-11  Justin Squirek  <squirek@adacore.com>

gcc/ada/

	* par-ch6.adb (Scan_Body_Or_Expression_Function): Add additional check
	to make sure a given expression function is properly parenthesized.

gcc/testsuite/

	* gnat.dg/expr_func4.adb: New testcase.

From-SVN: r256517

gcc/ada/ChangeLog

+2018-01-11  Justin Squirek  <squirek@adacore.com>
+
+	* par-ch6.adb (Scan_Body_Or_Expression_Function): Add additional check
+	to make sure a given expression function is properly parenthesized.
+
 2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>
 
 	* sem_ch6.adb (Analyze_Subprogram_Body_Helper): Check the

gcc/ada/par-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- --
@@ -873,7 +873,25 @@ package body Ch6 is
                     New_Node
                       (N_Expression_Function, Sloc (Specification_Node));
                   Set_Specification (Body_Node, Specification_Node);
-                  Set_Expression (Body_Node, P_Expression);
+                  declare
+                     Expr : constant Node_Id := P_Expression;
+                  begin
+                     Set_Expression (Body_Node, Expr);
+
+                     --  Check that the full expression is properly
+                     --  parenthesized since we may have a left-operand that is
+                     --  parenthesized but that is not one of the allowed cases
+                     --  with syntactic parentheses.
+
+                     if not (Paren_Count (Expr) /= 0
+                              or else Nkind_In (Expr, N_Aggregate,
+                                                      N_Extension_Aggregate,
+                                                      N_Quantified_Expression))
+                     then
+                        Error_Msg ("expression function must be enclosed "
+                          & "in parentheses", Sloc (Expr));
+                     end if;
+                  end;
 
                   --  Expression functions can carry pre/postconditions
 

gcc/testsuite/ChangeLog

+2018-01-11  Justin Squirek  <squirek@adacore.com>
+
+	* gnat.dg/expr_func4.adb: New testcase.
+
 2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>
 
 	* gnat.dg/pure_subp_body.adb, gnat.dg/pure_subp_body_pkg.ads: New

gcc/testsuite/gnat.dg/expr_func4.adb

+--  { dg-do compile }
+
+procedure Test_Exp is
+   function X return Boolean is
+     (Integer'Size = 32) or else (Float'Size = 32);  -- { dg-error "expression function must be enclosed in parentheses" }
+begin
+   null;
+end;