Bug 18990 – Failing class instantiations ignored in UDAs

This compiles without error: struct Attr { A h; } @Attr(new A(3)) // Line 6 class A {} static assert(!__traits(compiles, new A(3))); Clearly, line 6 should fail, since new A(3) doesn't compile elsewhere. This issue seems to cause problem with std.traits.getSymbolsByUDA: import std.traits; static assert(!getSymbolsByUDA!(mixin(__MODULE__), Attr).length); static assert(hasUDA!(A, Attr)); clearly, if hasUDA is true, then getSymbolsByUDA should return that symbol, but it doesn't. This could be a separate issue, but I'm not sure.

What version of the compiler are you using? I tried compiling your example with git HEAD master and the result was: test.d(6): Error: no constructor for `A`

This was under 2.080.0, which I just realized isn't the newest. It's indeed fixed in 2.080.1. Sorry for the noise. :p