order of static constructor execution

[Walter Bright]

Currently, it is performed as a strictly "depth-first" traversal of the 
graph defined by the import statements. As we've been discussing here, 
this works great until one has circular imports, meaning the depth-first 
graph has a loop in it.

The current behavior on detecting a loop is to quit with an error message.

The problems are:

1. The cycles are not easily gotten rid of when they are the result of 
template mixins.

2. Trying to analyze the static constructors to see what the 
dependencies actually are is fraught with unsolvable problems.


So, I propose the following:

1. Attempt the depth-first traversal of the static constructors.

2. If a loop is detected, rather than issuing an error message, simply 
arbitrarily pick one order and continue constructing.


The mitigating rationale is that modules that import each other are 
presumably written by the same person or team, and so that person is in 
the best place to explicitly control dependencies themselves.


I'm not happy with this solution, but it seems to be the best compromise 
I can come up with.

What do you think?