===================================================================
@@ -8831,6 +8831,19 @@
then
null;
+ -- Finally, the expression may be a qualified expression whose
+ -- own expression is a possibly overloaded function call. The
+ -- qualified expression is needed to be disambiguate the call,
+ -- but it appears in a context in which a name is needed, forcing
+ -- the use of a conversion.
+ -- In Ada2012 a qualified expression is a name, and this idiom
+ -- is not needed any longer.
+
+ elsif Nkind (Orig_N) = N_Qualified_Expression
+ and then Nkind (Expression (Orig_N)) = N_Function_Call
+ then
+ null;
+
-- Here we give the redundant conversion warning. If it is an
-- entity, give the name of the entity in the message. If not,
-- just mention the expression.
If the argument of a conversion is a qualified expression with the same type, the compiler will warn that the conversion is redundant. However, the qualifi- cation may be used to disambiguate a function call in an context that requires a name, and the conversion is used to provide it. This patch disables the warning in this special case. The following must compile quietly: gcc -c -gnatwa redconv.adb --- procedure RedConv is type E is record C : Integer; end record; type EE is new E; function Get return E is R : constant E := (C => 2); begin return R; end Get; function Get return EE is R : constant EE := (C => 1); begin return R; end Get; V : Integer; begin V := 1 + E (E'(Get)).C; V := 1 + EE (EE'(Get)).C; if V > 5 then null; end if; end RedConv; Tested on x86_64-pc-linux-gnu, committed on trunk 2010-09-10 Ed Schonberg <schonberg@adacore.com> * sem_res.adb (Resolve_Type_Conversion): Do not warn on a redundant conversion is the expression is a qualified expression used to disambiguate a function call.