Surprisingly, a Range attribute reference many not be used as a signed
integer type reference. This patch gives a clearer error message in
this case as shown by this example program:
1. package Typ_Is_Range is
2. S : constant String := "abc";
3. type T is range S'Range;
|
>>> Range attribute not allowed here, use First .. Last
4. end Typ_Is_Range;
Tested on x86_64-pc-linux-gnu, committed on trunk
2012-02-22 Robert Dewar <de...@adacore.com>
* par-ch3.adb (P_Signed_Integer_Type_Definition): Specialize
error message for 'Range.
Index: par-ch3.adb
===================================================================
--- par-ch3.adb (revision 184470)
+++ par-ch3.adb (working copy)
@@ -6,7 +6,7 @@
-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2012, 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- --
@@ -2279,13 +2279,30 @@
Scan; -- past RANGE
end if;
- Expr_Node := P_Expression;
- Check_Simple_Expression (Expr_Node);
- Set_Low_Bound (Typedef_Node, Expr_Node);
- T_Dot_Dot;
- Expr_Node := P_Expression;
- Check_Simple_Expression (Expr_Node);
- Set_High_Bound (Typedef_Node, Expr_Node);
+ Expr_Node := P_Expression_Or_Range_Attribute;
+
+ -- Range case (not permitted by the grammar, this is surprising but
+ -- the grammar in the RM is as quoted above, and does not allow Range).
+
+ if Expr_Form = EF_Range_Attr then
+ Error_Msg_N
+ ("Range attribute not allowed here, use First .. Last", Expr_Node);
+ Set_Low_Bound (Typedef_Node, Expr_Node);
+ Set_Attribute_Name (Expr_Node, Name_First);
+ Set_High_Bound (Typedef_Node, Copy_Separate_Tree (Expr_Node));
+ Set_Attribute_Name (High_Bound (Typedef_Node), Name_Last);
+
+ -- Normal case of explicit range
+
+ else
+ Check_Simple_Expression (Expr_Node);
+ Set_Low_Bound (Typedef_Node, Expr_Node);
+ T_Dot_Dot;
+ Expr_Node := P_Expression;
+ Check_Simple_Expression (Expr_Node);
+ Set_High_Bound (Typedef_Node, Expr_Node);
+ end if;
+
return Typedef_Node;
end P_Signed_Integer_Type_Definition;
