This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of WP status.

3132. Library needs to ban macros named expects or ensures

Section: [macro.names] Status: WP Submitter: Tim Song Opened: 2018-06-30 Last modified: 2018-11-13

Priority: 0

View all other issues in [macro.names].

View all issues with WP status.


expects and ensures are not technically described as attribute-tokens when used in a contract-attribute-specifier, so the existing prohibition in [macro.names] doesn't apply to them.

The remaining special identifiers used by the contract attributes are all already covered by existing wording: assert is also a library name so falls under p1, default is a keyword, and both axiom and audit were added to Table 4.

[2018-07-20 Status to Tentatively Ready after five positive votes on the reflector.]

[2018-11, Adopted in San Diego]

Proposed resolution:

This wording is relative to N4762.

  1. Change [macro.names] p2 as indicated:

    -2- A translation unit shall not #define or #undef names lexically identical to keywords, to the identifiers listed in Table 4, or to the attribute-tokens described in 9.11 [dcl.attr], or to the identifiers expects or ensures.