Here, in 20.00.25, this seems to "function" just fine:
TCC 20.00.25 x64 Windows 7 [Version 6.1.7601]
TCC: No functions defined
[TEST]function test foo
[TEST]function test bar
TCC: No aliases defined
[TEST]alias test foo
[TEST]alias test bar
I've been working with a few aliases lately and noticed that I now have to *unalias the existing aliases before redefining a newer version at the command line. Made me wonder what was happening for awhile.
Not the expected behavior since I didn't observe this issue in V19. Didn't check any further back.
I read several aliases from a file and multiple definitions for the same alias does not produce multiple definitions, LILO.
Conclusion: The multiple alias with same name behavior only seems to manifest when working with aliases at the V20 command line.