diff options
Diffstat (limited to 'gcc/ada/sem_util.adb')
| -rw-r--r-- | gcc/ada/sem_util.adb | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb index 8e6a2a2..edf1fec 100644 --- a/gcc/ada/sem_util.adb +++ b/gcc/ada/sem_util.adb @@ -2437,7 +2437,8 @@ package body Sem_Util is (Defining_Identifier (Associated_Node_For_Itype (Typ)))); - -- For generic formal type, return Int'Last (infinite) (why ???) + -- For generic formal type, return Int'Last (infinite). + -- See comment preceding Is_Generic_Type call in Type_Access_Level. elsif Is_Generic_Type (Root_Type (Typ)) then return UI_From_Int (Int'Last); @@ -12719,7 +12720,20 @@ package body Sem_Util is end if; end if; - -- Return library level for a generic formal type (why???) + -- Return library level for a generic formal type. This is done because + -- RM(10.3.2) says that "The statically deeper relationship does not + -- apply to ... a descendant of a generic formal type". Rather than + -- checking at each point where a static accessibility check is + -- performed to see if we are dealing with a formal type, this rule is + -- implemented by having Type_Access_Level and Deepest_Type_Access_Level + -- return extreme values for a formal type; Deepest_Type_Access_Level + -- returns Int'Last. By calling the appropriate function from among the + -- two, we ensure that the static accessibility check will pass if we + -- happen to run into a formal type. More specifically, we should call + -- Deepest_Type_Access_Level instead of Type_Access_Level whenever the + -- call occurs as part of a static accessibility check and the error + -- case is the case where the type's level is too shallow (as opposed + -- to too deep). if Is_Generic_Type (Root_Type (Btyp)) then return Scope_Depth (Standard_Standard); |