declaration/expression

[Ellery Newcomer]

Sorry for not posting this in learn, but I'd also like to hear the
Language Designer's input on this one.

How does dmd resolve the declaration/expression ambiguity?

My first instinct would be to try the declaration, and if it doesn't
work because the type doesn't exist or something like that then try the
expression, or vice versa. But that could easily lead to undefined and
unexpected behavior. what if both are valid?

Are there any straightforward rules for determining how to proceed?

And I might be wrong, but I don't think any of this is mentioned in the
spec? Should it be?

I can think of a number of examples, most of which dmd handles
gracefully. Here are a couple which, though contrived, seem to
illustrate that the rules are complicated, or more so than I would
conceive off the top of my head. Is the compiler doing what it should,
and if so, how?

import tango.io.Stdout;
void main(){
    int[4] i = [1,2,3,4];
    T(t); // compiler: I think this is an expression *barf*
    t(i[])(i[]); //compiler: I think this is a declaration *barf*
}

class T{
    public T opCall(int[] i){
        Stdout(i).newline;
        return this;
    }
}