March 28 [Issue 24465] New: Tuple does not get a copy constructor when its members need it | ||||
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https://issues.dlang.org/show_bug.cgi?id=24465 Issue ID: 24465 Summary: Tuple does not get a copy constructor when its members need it Product: D Version: D2 Hardware: All OS: All Status: NEW Severity: normal Priority: P1 Component: phobos Assignee: nobody@puremagic.com Reporter: issues.dlang@jmdavisProg.com An example: --- import std.typecons; void main() { Tuple!(int, S) t; foo(t); } struct S { int i; this(ref return scope inout(S) rhs) scope @trusted inout pure nothrow { this.i = rhs.i; } } void foo(Tuple!(int, S)) { } --- It fails with --- bug.d(6): Error: function `foo` is not callable using argument types `(Tuple!(int, S))` bug.d(6): `struct Tuple` does not define a copy constructor for `Tuple!(int, S)` to `Tuple!(int, S)` copies bug.d(19): `bug.foo(Tuple!(int, S))` declared here --- I _think_ that the problem is that this constructor --- this(U)(U another) if (areBuildCompatibleTuples!(typeof(this), U)) { field[] = another.field[]; } --- is managing to serve as an rvalue constructor, which unfortunately, is incompatible with copy constructors (I'm not convinced that it should be, but it is). But regardless of what the exact reason that it's currently failing is, it should work to create and copy Tuples which contain types with copy constructors. -- |
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