[Issue 17927] [scope] `scope inout` parameter value can be escaped via return

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17927

--- Comment #7 from Walter Bright <bugzilla at digitalmars.com> ---
Spec pull: https://github.com/dlang/dlang.org/pull/1914

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