In GNU Emacs 23.0.60.1 (i686-pc-linux-gnu, GTK+ Version 2.12.0)
 of 2008-11-26 on geert-laptop
Windowing system distributor `The X.Org Foundation', version 11.0.10300000


When a C/C++ file contains mixed struct/function definitions,
which-func-mode gets confused.

To reproduce (see also the comments in the test case file):

1. open the test case file whichfunc-testcase.cpp
2. make sure which-func-mode is enabled (M-x which-func-mode)
3. put the point within the funcA() definition
4. the modeline shows "structA", not the expected "funcA"

In the following I'll describe the problem in somewhat more detail.

In `which-function()' it is assumed that the entries from
`imenu--index-alist' are ordered by buffer possition.  `which-function()'
does a linear search through the items, and as soon as a buffer position
is encountered greater than point, the search stops.  However, when
submenu's are present in `imenu--index-alist', the items are not
necessarily ordered by buffer position anymore:

  For the testcase the imenu--index-alist variable looks like this:

     (("Class"
       ("structA" . #<marker at 2 in whichfunc-testcase.cpp>)
       ("structB" . #<marker at 63 in whichfunc-testcase.cpp>))
      ("funcA" . #<marker at 34 in whichfunc-testcase.cpp>)
      ("funcB" . #<marker at 96 in whichfunc-testcase.cpp>))

The attached patch ensures the linear search through `menu--index-alist
does not end prematurely, and all items are taken into account.  This
fixes the problem.