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January 18, 2011 enum of struct not calling constructor | ||||
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Example 1: import std.stdio; enum WindowSizes : QSize { Minimum = QSize(10) } struct QSize { int store; this(int x) { store = x + 10; } } void main() { auto foo = WindowSizes.Minimum; assert(foo.store == 10); // What? auto bar = QSize(10); assert(bar.store == 20); } It appears the constructor is never called for the enum. It does field by field assignments instead, just take a look at this case: import std.stdio; enum WindowSizes : Inverted { Minimum = Inverted(10, 20) } struct Inverted { int x; int y; this(int in_x, int in_y) { x = in_y; y = in_x; } } void main() { auto foo = WindowSizes.Minimum; assert(foo.x == 10); assert(foo.y == 20); auto bar = Inverted(10, 20); assert(bar.x == 20); assert(bar.y == 10); } As can be seen, this could be a potential source of bugs. Should I file it? |
January 18, 2011 Re: enum of struct not calling constructor | ||||
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Posted in reply to Andrej Mitrovic | On Tuesday, January 18, 2011 08:44:02 Andrej Mitrovic wrote:
> Example 1:
>
> import std.stdio;
>
> enum WindowSizes : QSize
> {
> Minimum = QSize(10)
> }
>
> struct QSize
> {
> int store;
> this(int x)
> {
> store = x + 10;
> }
> }
>
> void main()
> {
> auto foo = WindowSizes.Minimum;
> assert(foo.store == 10); // What?
>
> auto bar = QSize(10);
> assert(bar.store == 20);
> }
>
> It appears the constructor is never called for the enum. It does field by field assignments instead, just take a look at this case:
>
> import std.stdio;
>
> enum WindowSizes : Inverted
> {
> Minimum = Inverted(10, 20)
> }
>
> struct Inverted
> {
> int x;
> int y;
> this(int in_x, int in_y)
> {
> x = in_y;
> y = in_x;
> }
> }
>
> void main()
> {
> auto foo = WindowSizes.Minimum;
> assert(foo.x == 10);
> assert(foo.y == 20);
>
> auto bar = Inverted(10, 20);
> assert(bar.x == 20);
> assert(bar.y == 10);
> }
>
> As can be seen, this could be a potential source of bugs. Should I file it?
Absolutely.
- Jonathan M Davis
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January 18, 2011 Re: enum of struct not calling constructor | ||||
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http://d.puremagic.com/issues/show_bug.cgi?id=5460 |
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