work around GCC 6~11 ADL bug

[pgroke-dt]

see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51577 ADL seems to work properly when we do the SFINAE check via the return type, but not when using a dummy template parameter

fix #3992

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[asoffer]

Generally looks good. Please sign the CLA, and we'll get this merged.

[pgroke-dt]

The CLA should be signed, but somehow it still doesn't work. The issue is being discussed here: https://github.com/google/closure-compiler/pull/3988 In the meantime I will update the PR to use trailing return type as you requested.

[pgroke-dt]

@asoffer Sorry for taking so long, but the CLA check is finally green now.

[pgroke-dt]

@asoffer Hi. I made the changes you requested and the CLA check is green. Is there anything blocking us from moving forward with this?

[pgroke-dt]

@asoffer @derekmauro I'd really like to proceed with this. Please let me know if there's something I need to do before this can be merged.

[Krzmbrzl]

@asoffer @derekmauro @dinord could someone of you please look into this? This bug is what is keeping me from moving to following HEAD of googletest in my projects as they fail to compile :eyes:

[bencsikandrei]

is there any news on this one?

[Krzmbrzl]

Unfortunately not and I have the feeling that my pings to @asoffer @derekmauro and @dinord didn't get through :shrug: