Error checks are added to disallow index constraints given with a
mixture of constrained and fixed-lower-bound ranges, and also to
disallow an index constraint with a fixed-lower-bound index applied to a
type or subtype with fixed-lower-bound indexes.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* sem_ch3.adb (Constrain_Array): Add error checking for
fixed-lower-bound and constrained index ranges applied
inappropriately on subtypes of unconstrained and
fixed-lower-bound array types.
(Constrain_Index): Correct and refine comment related to
fixed-lower-bound index ranges.diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -13373,8 +13373,40 @@ package body Sem_Ch3 is
-- entity will need to be marked as being a fixed-lower-bound
-- array subtype.
- if Is_Fixed_Lower_Bound_Index_Subtype (Etype (S)) then
- Is_FLB_Array_Subtype := True;
+ if S = First (Constraints (C)) then
+ Is_FLB_Array_Subtype :=
+ Is_Fixed_Lower_Bound_Index_Subtype (Etype (S));
+
+ -- If the parent subtype (or should this be Etype of that?)
+ -- is an FLB array subtype, we flag an error, because we
+ -- don't currently allow subtypes of such subtypes to
+ -- specify a fixed lower bound for any of their indexes,
+ -- even if the index of the parent subtype is a "range <>"
+ -- index.
+
+ if Is_FLB_Array_Subtype
+ and then Is_Fixed_Lower_Bound_Array_Subtype (T)
+ then
+ Error_Msg_NE
+ ("index with fixed lower bound not allowed for subtype "
+ & "of fixed-lower-bound }", S, T);
+
+ Is_FLB_Array_Subtype := False;
+ end if;
+
+ elsif Is_FLB_Array_Subtype
+ and then not Is_Fixed_Lower_Bound_Index_Subtype (Etype (S))
+ then
+ Error_Msg_NE
+ ("constrained index not allowed for fixed-lower-bound "
+ & "subtype of}", S, T);
+
+ elsif not Is_FLB_Array_Subtype
+ and then Is_Fixed_Lower_Bound_Index_Subtype (Etype (S))
+ then
+ Error_Msg_NE
+ ("index with fixed lower bound not allowed for "
+ & "constrained subtype of}", S, T);
end if;
Next (Index);
@@ -14396,9 +14428,9 @@ package body Sem_Ch3 is
Set_First_Rep_Item (Def_Id, First_Rep_Item (T));
-- If this is a range for a fixed-lower-bound subtype, then set the
- -- index itype's lower bound to the FLB and the index type's upper bound
- -- to the high bound of the index subtype's high bound, mark the itype
- -- as an FLB index subtype, and set the range's Etype to the itype.
+ -- index itype's low bound to the FLB and the index itype's upper bound
+ -- to the high bound of the parent array type's index subtype. Also,
+ -- mark the itype as an FLB index subtype.
if Nkind (S) = N_Range and then Is_FLB_Index then
Set_Scalar_Range
