https://github.com/dlang/dmd/pull/11392 implies that the language designers decided not to flatten template argument tuples (or whatever is he right name) passed to __traits(isSame). The PR partially implements the decision but makes no distinction between a singleton tuple and a scalar, which introduces an undesirable inconsistency:
static assert(is(int == AliasSeq!int)); // false as expected
static assert(__traits(isSame, int, AliasSeq!int); // true, but false is expected
Comment #1 by robert.schadek — 2024-12-13T19:13:42Z