exp_dist.adb: Minor comment updates.

2009-07-13  Bob Duff  <duff@adacore.com>

	* exp_dist.adb: Minor comment updates.

From-SVN: r149581

gcc/ada/ChangeLog

+2009-07-13  Bob Duff  <duff@adacore.com>
+
+	* exp_dist.adb: Minor comment updates.
+
 2009-07-13  Gary Dismukes  <dismukes@adacore.com>
 
 	* sem_ch10.adb, sem_ch12.adb, gnat1drv.adb, exp_ch4.adb: Fix casing of

gcc/ada/exp_dist.adb

@@ -8672,7 +8672,10 @@ package body Exp_Dist is
             Use_Opaque_Representation : Boolean;
 
          begin
-            --  The following test needs a comment ???
+            --  For a derived type, we can't go past the base type (to the
+            --  parent type) here, because that would cause the attribute's
+            --  formal parameter to have the wrong type; hence the Base_Type
+            --  check here.
 
             if Is_Itype (Typ) and then Typ /= Base_Type (Typ) then
                Build_From_Any_Function
@@ -9499,7 +9502,10 @@ package body Exp_Dist is
             --  opaque sequence of bytes.
 
          begin
-            --  The following test needs a comment ???
+            --  For a derived type, we can't go past the base type (to the
+            --  parent type) here, because that would cause the attribute's
+            --  formal parameter to have the wrong type; hence the Base_Type
+            --  check here.
 
             if Is_Itype (Typ) and then Typ /= Base_Type (Typ) then
                Build_To_Any_Function
@@ -10631,7 +10637,10 @@ package body Exp_Dist is
          --  Start of processing for Build_TypeCode_Function
 
          begin
-            --  The following test needs a comment ???
+            --  For a derived type, we can't go past the base type (to the
+            --  parent type) here, because that would cause the attribute's
+            --  formal parameter to have the wrong type; hence the Base_Type
+            --  check here.
 
             if Is_Itype (Typ) and then Typ /= Base_Type (Typ) then
                Build_TypeCode_Function