Bug 8862 – order of declaration of a function and compile time execution

I think these two codes below are equivalent, but DMD outputs two lines when compiling the first. http://dpaste.dzfl.pl/3bcc6b95 http://dpaste.dzfl.pl/167ef2ac I am not sure this is caused by CTFE, template mixin, something else, or some combination of them.

Reduced test case. The the line of initialization of the 'b' variable matters. If it's defined after bar() it compiles, otherwise it doesn't compile: mixin template Foo() { static Spam[1] b = bar(); // Bad. static Spam[1] bar() { Spam[1] result; return result; } // static Spam[1] b = bar(); // Good. } struct Spam { mixin Foo!(); } void main() {} Initializing 'b' before defining bar() gives the errors: test.d(3): Error: function test.Spam.Foo!().bar circular dependency. Functions cannot be interpreted while being compiled test.d(2): called from here: bar() test.d(2): called from here: bar() test.d(10): Error: mixin test.Spam.Foo!() error instantiating

(In reply to comment #1) > Reduced test case. The line of initialization of the 'b' variable matters. > If it's defined after bar() it compiles, otherwise it doesn't compile: Thanks, but the behavior you reproduced seems different from mine. In my case, both compiles while the first outputs error-like messages.

(In reply to comment #2) > (In reply to comment #1) > > Reduced test case. The line of initialization of the 'b' variable matters. > > If it's defined after bar() it compiles, otherwise it doesn't compile: > > Thanks, but the behavior you reproduced seems different from mine. > In my case, both compiles while the first outputs error-like messages. I see. Then try to minimize the code yourself. And then attach/paste it here instead of dpaste, please.

> I see. Then try to minimize the code yourself. And then attach/paste it here > instead of dpaste, please. Actually I was trying to reduce test case for a bug http://d.puremagic.com/issues/show_bug.cgi?id=8865 and came up with another (this) one, so it was difficult for me. Thanks to your code, I managed to minimize see below: void main() { F!10 x; } struct F(int n) { mixin I!n; } mixin template I(int n) { int value; static F[1] x = get_xs(); // compiles, but outputs: "error.d(14): called from here: get_xs()" static F[1] get_xs() { return [F(0)]; } //static F[1] x = get_xs(); // compiles, without output. }

The difference is simply that bearophile's case is using git head. The "circular dependency" message was missing from previous compiler releases. This situation is actually a bit strange. It's using sequential semantics, as if it were in a function body, rather than the out-of-order semantics it would have in a struct. This isn't actually a CTFE bug - it should be possible to reproduce this bug without using CTFE.

Works with git-head, so I'm sure that it's a duplication of one of already fixed forward reference issue.