> std.functional is not importing std.uni, so count!"std.uni.toLower(a) == std.uni.toLower(b)"(...) should trigger error. But because of bug 313/314, std.uni.toLower is accidentally accessible via "string lambdas".

Where does `std.functional` come in play? You mean `std.algorithm`?

Anyway I'm asking about the new code, if you use `import std.uni : toLower;`, then `std.uni.toLower` shouldn't be available, only `toLower` should.