To: J3                                                     J3/16-172
From: Steve Lionel
Subject: Missing constraint from GENERIC statement
Date: 2016 March 14

Reference: 16-007

Fortran 2015 adds the GENERIC statement as an alternative to using
interface blocks for declaring generic interfaces. 12.4.3.2 (Interface
block) includes a constraint prohibiting naming a specific procedure
more than once:

C1209 (R1201) An interface-specification in a generic interface block
shall not specify a procedure that was specified previously in any
accessible interface with the same generic identifier.

but 12.4.3.3 (GENERIC statement) lacks a corresponding constraint. A
correction is supplied:

EDIT:

[290:4+, 12.4.3.3]

Insert the constraint:

"C1209+ (R1210) A <specific-procedure> in a GENERIC statement shall not
specify a procedure that was specified previously in any accessible
interface with the same generic identifier."