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

G.6 [dcl]: Declarations [ifndr.dcl]

G.6.3[ifndr:dcl.fct.default.inline.same.defaults]
Specified in: [dcl.fct.default]

1
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If the accumulated set of default arguments for a given inline function with definitions in multiple translation units is different at the end of different translation units, the program is ill-formed, no diagnostic required.
2
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[Example 1: 

Translation unit #1:inline int f(int x, int y = 2); inline int f(int x = 1, int y); // IFNDR, default arguments of f are 1 and 2

Translation unit #2:inline int f(int x = 3, int y = 4); // IFNDR, default arguments of f are 3 and 4 — end example]