Different .stringof format for CT Sequences depending on content

[dlangBugzillaToGithub]

Simen Kjaeraas reported this on 2019-08-12T12:29:27Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=20125

Description

import std.meta;
static assert(AliasSeq!().stringof                 == "()");
static assert(AliasSeq!(1).stringof                == "tuple(1)");
static assert(AliasSeq!(1,2).stringof              == "tuple(1, 2)");
static assert(AliasSeq!(int).stringof              == "(int)");
static assert(AliasSeq!(int, int).stringof         == "(int, int)");
static assert(AliasSeq!(int, 2).stringof           == "tuple((int), 2)");
static assert(AliasSeq!(int, 2, int, int).stringof == "tuple((int), 2, (int), (int))");

As we can see above, CT sequences containing at least one value has a "tuple" prefix, while others don't. Not only that, but mixed sequences wrap every type in (brackets).