Re: Recursive template instantiation
On 03/13/2017 11:58 PM, Stefan Koch wrote:
On Monday, 13 March 2017 at 22:05:24 UTC, Jack Applegame wrote:
Is this a bug?
No it's not
struct C
{
B!C;
}
is an error.
Howto compute C ? <--\
let's check the members; |
The member needs a template. |
Howto compute the template ? |
let's compute the parameters. |
What is the first Parameter ? |
Its C. |
Howoto compute C---/
I don't think that's it.
Here's a variant where B is not instantiated with C:
struct A()
{
~this() { enum s = C.sizeof; }
}
struct B() { A!() foo; }
struct C { B!() bar; }
How to compute C?
Check members.
For member `B!() bar;`, resolve `B!()`.
Check members of `B!()`.
For member `A!() foo;` resolve `A!()`.
Check members of `A!()`.
No members => size = 0 (or rather 1, I guess).
Bubble up.
But the compiler seems to get confused by the destructor. I guess it
incorrectly(?) sees a need to analyze C again before it can finish up
`A!()`?
Re: Recursive template instantiation
On 03/14/2017 12:02 AM, Stefan Koch wrote:
On Monday, 13 March 2017 at 22:59:36 UTC, ag0aep6g wrote:
[...]
struct A(T) {
void m() {
char[T.sizeof] data;
}
}
/* ... rest as above ... */
I don't see how the destructor makes a difference. Soo, bug?
Try to use m.
Works no problem?
struct A(T) {
void m() {
char[T.sizeof] data;
import std.stdio;
writeln(T.sizeof);
}
}
struct B(T) {
A!T foo;
}
struct C {
B!C bar;
}
void main() {
C c;
c.bar.foo.m();
}
Prints "1".
Re: Recursive template instantiation
On Monday, 13 March 2017 at 22:59:36 UTC, ag0aep6g wrote:
On 03/13/2017 03:26 PM, Jack Applegame wrote:
I'm pretty sure that this code should compile
(https://dpaste.dzfl.pl/cf1e1ee6ef4b):
struct A(T) {
~this() {
char[T.sizeof] data;
}
}
struct B(T) {
A!T foo;
}
struct C {
B!C bar;
}
void main() {
C c;
}
But it doesn't:
/d300/f416.d(3): Error: struct f416.C no size because of
forward
reference /d300/f416.d(12): Error: template instance
f416.B!(C) error
instantiating
It compiles when it's a normal method instead of a destructor:
struct A(T) {
void m() {
char[T.sizeof] data;
}
}
/* ... rest as above ... */
I don't see how the destructor makes a difference. Soo, bug?
Try to use m.
Re: Recursive template instantiation
On 03/13/2017 03:26 PM, Jack Applegame wrote:
I'm pretty sure that this code should compile
(https://dpaste.dzfl.pl/cf1e1ee6ef4b):
struct A(T) {
~this() {
char[T.sizeof] data;
}
}
struct B(T) {
A!T foo;
}
struct C {
B!C bar;
}
void main() {
C c;
}
But it doesn't:
/d300/f416.d(3): Error: struct f416.C no size because of forward
reference /d300/f416.d(12): Error: template instance f416.B!(C) error
instantiating
It compiles when it's a normal method instead of a destructor:
struct A(T) {
void m() {
char[T.sizeof] data;
}
}
/* ... rest as above ... */
I don't see how the destructor makes a difference. Soo, bug?
Re: Recursive template instantiation
On Monday, 13 March 2017 at 22:05:24 UTC, Jack Applegame wrote:
Is this a bug?
No it's not
struct C
{
B!C;
}
is an error.
Howto compute C ? <--\
let's check the members; |
The member needs a template. |
Howto compute the template ? |
let's compute the parameters. |
What is the first Parameter ? |
Its C. |
Howoto compute C---/
Re: Recursive template instantiation
Is this a bug?
Recursive template instantiation
I'm pretty sure that this code should compile
(https://dpaste.dzfl.pl/cf1e1ee6ef4b):
struct A(T) {
~this() {
char[T.sizeof] data;
}
}
struct B(T) {
A!T foo;
}
struct C {
B!C bar;
}
void main() {
C c;
}
But it doesn't:
/d300/f416.d(3): Error: struct f416.C no size because of forward
reference /d300/f416.d(12): Error: template instance f416.B!(C)
error instantiating
Notice that the same C++ code compiles without problems:
template struct A {
~A() {
char data[sizeof(T)];
}
};
template struct B {
A foo;
};
struct C {
B bar;
};
int main() {
C c;
}
A simple recursion is compiled successfully
(https://dpaste.dzfl.pl/5a8ff73bfa88):
struct A(T) {
~this() {
char[T.sizeof] data;
}
}
struct C {
A!C bar;
}
void main() {
C c;
}
