Bug 13773 – std.traits.ReturnType does not resolve inout

cat > bug.d << CODE import std.traits; struct Foo { inout(int)[] keys() inout @property { return null; } } void main() { Foo m; const(Foo) c; immutable(Foo) i; pragma(msg, typeof(m.keys), ", ", ReturnType!(m.keys)); pragma(msg, typeof(c.keys), ", ", ReturnType!(c.keys)); pragma(msg, typeof(i.keys), ", ", ReturnType!(i.keys)); } CODE dmd -c bug ---- int[], inout(int)[] const(int)[], inout(int)[] immutable(int)[], inout(int)[] ----

I think this should be marked as invalid or changed as a compiler enhancement, because: 1. ReturnType takes an alias (through the index 0 of the TupleParameter). 2. Currently alias parameter cannot handle the runtime context of the expression, so ReturnType!(m.keys), ReturnType!(c.keys), and ReturnType!(i.keys) are perfectly same with ReturnType!(Foo.keys). 3. The return type of Foo.keys is inout(int)[].