diff options
Diffstat (limited to 'gcc/ada/a-cidlli.adb')
| -rw-r--r-- | gcc/ada/a-cidlli.adb | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/gcc/ada/a-cidlli.adb b/gcc/ada/a-cidlli.adb index 42bd3c48313..dbdc6de47d4 100644 --- a/gcc/ada/a-cidlli.adb +++ b/gcc/ada/a-cidlli.adb @@ -563,10 +563,24 @@ package body Ada.Containers.Indefinite_Doubly_Linked_Lists is LI, RI : Cursor; begin - if Target'Address = Source'Address then + + -- The semantics of Merge changed slightly per AI05-0021. It was + -- originally the case that if Target and Source denoted the same + -- container object, then the GNAT implementation of Merge did + -- nothing. However, it was argued that RM05 did not precisely + -- specify the semantics for this corner case. The decision of the + -- ARG was that if Target and Source denote the same non-empty + -- container object, then Program_Error is raised. + + if Source.Is_Empty then return; end if; + if Target'Address = Source'Address then + raise Program_Error with + "Target and Source denote same non-empty container"; + end if; + if Target.Busy > 0 then raise Program_Error with "attempt to tamper with cursors of Target (list is busy)"; |