An expression_function_declaration is a different syntactic category from
a subprogram_declaration. As a consequence, an expression function cannot
appear in a protected definition, i.e. cannot declare a protected operation.
Compiling essai.adb must yield:
essai.adb:4:07: an expression function is not a legal protected operation
essai.adb:7:07: an expression function is not a legal protected operation
---
pragma Ada_2012;
procedure Essai is
protected P1 is
function F1 return Integer is (1);
function F2 return Integer; -- ERROR
private
function F3 return Boolean is (False); -- ERROR
end P1;
protected body P1 is
function F2 return Integer is (1); -- OK
end P1;
begin
null;
end Essai;
Tested on x86_64-pc-linux-gnu, committed on trunk
2013-01-29 Ed Schonberg <[email protected]>
* sem_ch6.adb (Analyze_Expression_Function): An expression
function declaration is not a subprogram declaration, and thus
cannot appear in a protected definition.
Index: sem_ch6.adb
===================================================================
--- sem_ch6.adb (revision 195540)
+++ sem_ch6.adb (working copy)
@@ -408,6 +408,15 @@
-- that the expression can be inlined whenever possible.
else
+ -- An expression function that is not a completion is not a
+ -- subprogram declaration, and thus cannot appear in a protected
+ -- definition.
+
+ if Nkind (Parent (N)) = N_Protected_Definition then
+ Error_Msg_N
+ ("an expression function is not a legal protected operation", N);
+ end if;
+
New_Decl :=
Make_Subprogram_Declaration (Loc, Specification => Spec);
