!standard 11.5(20)                                   16-10-03  AI12-0202-1/01
!class Amendment 10-10-03
!status No Action (8-0-3) 18-06-23
!status work item 16-10-03
!status received 16-09-05
!priority Low
!difficulty Easy
!subject Tampering_Check
!summary

Add a new check name, Tampering_Check, that may be used in pragmas Suppress
and Unsuppress.

!problem

The tampering checks required for the predefined containers packages are in
practice very expensive, and compilers usually do not have enough information
to optimize them away.

!proposal

(See Summary.)

!wording

Add after 11.5(20):

Tampering_Check
    When an operation in an instance of a predefined container involves a
    tampering check, check that tampering with cursors or with elements is not
    currently prohibited (see A.18.2).

Add after A.18.2(264/2):

    NOTES
    ...
    50  Tampering checks can be suppressed via "pragma
    Suppress(Tampering_Check);" (see 11.5).

!discussion

This check is already implemented in the GNAT compiler, and has proved to be
quite popular among users of the containers who care about efficiency.

!ASIS

No ASIS effect.

!ACATS test

An ACATS C-Test is needed to check that Tampering_Check is recognized.

!appendix

From: Bob Duff
Sent: Monday, September 5, 2016  2:47 PM

> It's only a month before the ARG homework is due for the Pittsburgh ARG
> 	Bob Duff:
>           AI to define suppress check name Tampering_Check (see 
> discussion of AI12-0111-1 in meeting #54)

OK, here it is:

[This is version /01 of the AI - Editor.]

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From: Jeff Cousins
Sent: Thursday, September 8, 2016  7:40 AM

Seems straightforward enough.

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