https://issues.dlang.org/show_bug.cgi?id=12862
--- Comment #2 from Martin Nowak <c...@dawg.eu> --- Mmh, the codegen assertion vanished with this commit (https://github.com/D-Programming-Language/dmd/commit/9efe7f74c2462e8743f5a479cd04f9be733be4b0). I reproduced another test case for the issue. cat > bug.d << CODE struct FPoint { float x, y; } struct FRect { float left, top, right, bottom; static FRect calcBounds(FPoint[] ) { return FRect(); } } struct Matrix { FRect mapRect(FRect src) { FPoint[] pts = new FPoint[](1); pts[0].x = src.left; pts[0].y = src.top; return FRect.calcBounds(pts); } } // TODO: FPoint -> Point!T struct Path { @property FRect bounds() { if (points.length) return FRect(); else return FRect(); } FPoint[] points; } void foo() { Matrix mat; Path path; mat.mapRect(path.bounds); } CODE The issues first appeared with dmd2.060 and seems to be triggered by assigning tym = TYucent to 16 byte structs that consist of either 4 floats or 2 doubles in elstruct (https://github.com/D-Programming-Language/dmd/blob/5cc1c812227440d199f265dec8fb976bea7ad943/src/backend/cgelem.c#L3077). I don't understand that code good enough to fix the issue though. --