The expanded code for an instantiation may contain apparent ambiguities when
two subprograms that are generic formals or that depend on formal types become
homonyms after formals are replaced with actuals. In some cases, the ambiguity
can be resolved by favoring the innermost interpretation, when both of them
are declared within the instance.
No small example available.
Tested on x86_64-pc-linux-gnu, committed on trunk
2011-08-29 Ed Schonberg <[email protected]>
* sem_ch8.adb (Find_Renamed_Entity): Within an instance, use scope
depth of candidates to resolve a potentially spurious ambiguity between
two visible subprograms.
Index: sem_ch8.adb
===================================================================
--- sem_ch8.adb (revision 178191)
+++ sem_ch8.adb (working copy)
@@ -4841,7 +4841,9 @@
Set_Entity_Or_Discriminal (N, E);
if Ada_Version >= Ada_2012
- and then Nkind (Parent (N)) in N_Subexpr
+ and then
+ (Nkind (Parent (N)) in N_Subexpr
+ or else Nkind (Parent (N)) = N_Object_Declaration)
then
Check_Implicit_Dereference (N, Etype (E));
end if;
@@ -5531,13 +5533,30 @@
if Present (Inst) then
if Within (It.Nam, Inst) then
- return (It.Nam);
+ if Within (Old_S, Inst) then
+
+ -- Choose the innermost subprogram, which would
+ -- have hidden the outer one in the generic.
+
+ if Scope_Depth (It.Nam) <
+ Scope_Depth (Old_S)
+ then
+ return Old_S;
+
+ else
+ return It.Nam;
+ end if;
+ end if;
+
elsif Within (Old_S, Inst) then
return (Old_S);
+
else
return Report_Overload;
end if;
+ -- If not within an instance, ambiguity is real.
+
else
return Report_Overload;
end if;
