Annex G (informative) Ill-formed, no diagnostic required [ifndr]

G.4 [expr]: Expressions [ifndr.expr]

G.4.1[ifndr:expr.prim.req.always.sub.fail]
Specified in: [expr.prim.req.general]

1
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If the substitution of template arguments into a requirement would always result in a substitution failure, the program is ill-formed; no diagnostic required.
2
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[Example 1: template <typename T> concept C = requires { new int[-(int)sizeof(T)]; // IFNDR, the size of the allocation is required to be greater // than zero but can never be }; — end example]