diff options
Diffstat (limited to 'gcc/ada/stand.ads')
| -rw-r--r-- | gcc/ada/stand.ads | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/gcc/ada/stand.ads b/gcc/ada/stand.ads index 16f388d5fe6..33a184ccfbc 100644 --- a/gcc/ada/stand.ads +++ b/gcc/ada/stand.ads @@ -6,7 +6,7 @@ -- -- -- S p e c -- -- -- --- Copyright (C) 1992-2012, Free Software Foundation, Inc. -- +-- Copyright (C) 1992-2013, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- @@ -362,10 +362,23 @@ package Stand is -- identifier references to prevent cascaded errors. Any_Type : Entity_Id; - -- Used to represent some unknown type. Plays an important role in - -- avoiding cascaded errors, since any node that remains labeled with - -- this type corresponds to an already issued error message. Any_Type - -- is propagated to avoid cascaded errors from a single type error. + -- Used to represent some unknown type. Any_Type is the type of an + -- unresolved operator, and it is the type of a node where a type error + -- has been detected. Any_Type plays an important role in avoiding cascaded + -- errors, because it is compatible with all other types, and is propagated + -- to any expression that has a subexpression of Any_Type. When resolving + -- operators, Any_Type is the initial type of the node before any of its + -- candidate interpretations has been examined. If after examining all of + -- them the type is still Any_Type, the node has no possible interpretation + -- and an error can be emitted (and Any_Type will be propagated upwards). + -- + -- There is one situation in which Any_Type is used to legitimately + -- represent a case where the type is not known pre-resolution, and that + -- is for the N_Raise_Expression node. In this case, the Etype being set to + -- Any_Type is normal and does not represent an error. In particular, it is + -- compatible with the type of any constituent of the enclosing expression, + -- if any. The type is eventually replaced with the type of the context, + -- which plays no role in the resolution of the Raise_Expression. Any_Access : Entity_Id; -- Used to resolve the overloaded literal NULL |