import std.array; import std.range; import std.algorithm; class Foo { } void main() { auto result = iota(3).map!(i => new immutable Foo).array(); } /usr/include/dmd/phobos/std/conv.d(4028): Error: cannot implicitly convert expression (arg) of type immutable(Foo) to test.Foo /usr/include/dmd/phobos/std/conv.d(3931): Error: template instance std.conv.emplaceImpl!(immutable(Foo)).emplaceImpl!(immutable(Foo)) error instantiating /usr/include/dmd/phobos/std/array.d(115): instantiated from here: emplaceRef!(immutable(Foo), Foo, immutable(Foo)) test.d(9): instantiated from here: array!(MapResult!(__lambda1, Result))
Fix - https://github.com/D-Programming-Language/phobos/pull/3524
Reasons of this issue and issue 15313 are the same. Fixing issue 1513 also fixed this one.