[Voted into WP at March, 2010 meeting.]

Proposed resolution (October, 2009):

1. Change 7.6.2.2 [expr.unary.op] paragraph 3 as follows:

...For a qualified-id, if the member is a static member of type “T”, the type of the result is plain “pointer to T.” If the member is a non-static member of class C of type T, the type of the result is “pointer to member of class C of type T.,” and the program is ill-formed if C is an ambiguous base (6.5.2 [class.member.lookup]) of the class designated by the nested-name-specifier of the qualified-id....

2. Change 6.5.2 [class.member.lookup] paragraph 13 as follows:

[Note: Even if the result of name lookup is unambiguous, use of a name found in multiple subobjects might still be ambiguous (7.3.13 [conv.mem], 7.6.1.5 [expr.ref], 7.6.2.2 [expr.unary.op], 11.8.3 [class.access.base]). —end note] [Example:...

The resolution of issue 39 changed the diagnosis of ambiguity because of multiple subobjects from being a lookup error to being diagnosed where the result of the lookup is used. The formation of a pointer to member is one such context but was overlooked in the changes. 7.6.2.2 [expr.unary.op] paragraph 3 should have language similar to 7.6.1.5 [expr.ref] paragraph 5 and should be mentioned in the note in 6.5.2 [class.member.lookup] paragraph 13.