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[dcl.contract.func]/4 Missing IFNDR

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
55/100
Issue type
Documentation
Clarity
Mostly clear
Activity status
Active
Tech stack
cpp, latex, tex

Research direction

The issue points to missing IFNDR (ill-formed, no diagnostic required) clauses in the C++ standard draft. Start by reading the linked sections [dcl.contract.func]/4 and /5 and the IFNDR annex G.6.4. Compare the wording to identify the discrepancy: one IFNDR case about mismatched contract specifiers in first declarations across translation units is documented, but another about non-first declarations may be missing. Verify the draft's structure and propose an edit to the LaTeX source, likely in the relevant .tex files under the 'dcl' or 'ifndr' sections.

Written by the indexing model from the issue text.

Description

ub-ifndr

[dcl.contract.func]/4 says

A declaration D of a function or function template f that is not a first declaration shall have either no function-contract-specifier-seq or the same function-contract-specifier-seq (see below) as any first declaration F reachable from D.
If D and F are in different translation units, a diagnostic is required only if D is attached to a named module.
If a declaration F₁ is a first declaration of f in one translation unit and a declaration F₂ is a first declaration of f in another translation unit, F₁ and F₂ shall specify the same function-contract-specifier-seq, no diagnostic required ([ifndr:dcl.contract.func.mismatched.contract.specifiers]).

There are two IFNDR cases, one about not-the-first declarations and another is about first declarations.

However, G.6.4 is only about the latter case.

If two different first declarations of a function (which must therefore not be reachable from one another) do not have equivalent function contract specifiers the program is ill-formed, no diagnostic required.

BTW, [dcl.contract.func]/5 has a totally missing IFNDR

... If this condition is not met solely due to the comparison of two lambda-expressions that are contained within P₁ and P₂, no diagnostic is required.

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