module test; struct Foo { this (int i) { } } void bar(Foo foo = Foo(42)) { } void main() { bar(); } # dmd test.d Internal error: ..\ztc\out.c 1201 I briefly recall submitting similar bug-report a few months ago, but that one got fixed IIRC. I'll add more info as I find.
*** This issue has been marked as a duplicate of issue 2935 ***