Can you please give an example of what those tools were actually doing? Do you think they/other tools will work with modules without any modification?

-----Original Message-----
From: Ville Voutilainen <ville.voutilainen_at_[hidden]il.com>
Sent: Thursday, August 29, 2019 10:22 AM
To: sg15_at_lists.isocpp.org
Cc: Michael Spencer <bigcheesegs_at_gmail.com>; Olga Arkhipova <olgaark_at_microsoft.com>
Subject: Re: [SG15] module source suffixes

On Thu, 29 Aug 2019 at 20:03, Olga Arkhipova via SG15 <sg15_at_lists.isocpp.org> wrote:
>
> I’d like to better understand the reasons why people find new file extension for module interface sources problematic/undesirable. Can somebody describe some scenarios where new extension will cause problems while having modules with old extension will not?

A bit less than 20 years ago, half of my tools didn't think .cpp is a
c++ source file, and the other half
didn't think .C or .cc are. That was not a pleasant experience. While such problems are temporary by nature, they are annoying.