I've researched a bit though I still haven't come up with a solution.
Since the problem lies within (the most simple) constructor, I tried to
modify it for another outcome. If I supplied a generic parameter to the
pre-constructor the "Cannot evaluate at compile time" message
disappeared but two new errors appeared instead.
This is what I modified:
this()(float x, float y, float z) => this(T)(float x, float y, float z)
If I use this code instead, I get two other errors appearing:
Error: template test.DVECTOR2.__ctor(T) does not match any function
template declaration
This error and another one (individual to each statement) appears in the
following code statements:
Error: template test.DVECTOR2.__ctor(T) cannot deduce template function
from argument types !()(float,float)
DVECTOR2 m_zoom = DVECTOR2(2f, 2f);
Error: template test.DVECTOR2.__ctor(T) cannot deduce template function
from argument types !()(immutable(float),const(float))
immutable DVECTOR2 m_UP_DIR = DVECTOR2(0f, 1f, 0f);