Re: [9front] gefs unnamed substructure undefined behavior

[ori@eigenstate.org]

For plan9port/gcc, you can add the '-fplan9-extensions' flag,
and things will work for this, I believe.

(FWIW, I've ported to linux in order to use tsan and asan,
but didn't find it worthwhile to maintain the port; I can
try to find some of the hacks I put in place if you're
interested)

Quoth ashley <ashley@tilde.institute>:
> that seems cromulent to me.
> 
> I noticed this while trying to port gefs to plan9port/gcc it's just
> annoying is all. in any case the man page should reflect the actual
> behavior, and I agree that hard errors are far preferable to
> unspecified behavior if they're possible to detect statically.

How's this?

diff 051804186780ef7f3b2f4cb548be1dd0685de5fe uncommitted
--- a/sys/man/1/2c
+++ b/sys/man/1/2c
@@ -232,7 +232,7 @@
 A structure or union may contain unnamed substructures and subunions.
 The fields of the substructures or
 subunions can then be used as if they were members of the parent
-structure or union (the resolution of a name conflict is unspecified).
+structure or union.
 When a pointer to the outer structure or union is used in a context
 that is only legal for the unnamed substructure, the compiler promotes
 the type and adjusts the pointer value to point at the substructure.
@@ -241,6 +241,10 @@
 statement,
 the unnamed structure or union can be explicitly referenced
 by <struct variable>.<tagname>.
+If an enclosed structure or union contains a member with the same name as the enclosing structure,
+the enclosing structure takes priority.
+If an enclosing structure or union contains two structures with the same member,
+accessing the ambiguous member without disambiguation is an error.
 .TP
 \-
 A structure value can be formed with an expression such as