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Section: 19.15.2 [meta.type.synop] Status: NAD Submitter: United States Opened: 2017-02-03 Last modified: 2017-07-16
Priority: Not Prioritized
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Addresses US 10
A user specialization of any type trait should produce an ill-formed program, not merely one whose behavior is unspecified. See also the related comment re 19.18.3 [execpol.type].
Reword the paragraph as follows:
Unless otherwise specified, a program that adds specializations for any of the templates defined in this subclause is ill-formed; no diagnostic required.
See also 2909
[2017-07 Toronto Thurs Issue Prioritization]
NAD; what the standard says is that this is "undefined", not "unspecified".
This wording is relative to N4618.
Modify 19.15.2 [meta.type.synop] as indicated:
The behavior of a program that adds specializations for any of the templates defined in this subclause is undefined unless otherwise specified.