105 lines
2.4 KiB
Rust
105 lines
2.4 KiB
Rust
// run-pass
|
|
|
|
#![allow(dead_code)]
|
|
#![allow(unused_variables)]
|
|
#![allow(unreachable_code)]
|
|
// A regression test extracted from image-0.3.11. The point of
|
|
// failure was in `index_colors` below.
|
|
|
|
use std::ops::{Deref, DerefMut};
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct Luma<T: Primitive> { pub data: [T; 1] }
|
|
|
|
impl<T: Primitive + 'static> Pixel for Luma<T> {
|
|
type Subpixel = T;
|
|
}
|
|
|
|
pub struct ImageBuffer<P: Pixel, Container> {
|
|
pixels: P,
|
|
c: Container,
|
|
}
|
|
|
|
pub trait GenericImage: Sized {
|
|
type Pixel: Pixel;
|
|
}
|
|
|
|
pub trait Pixel: Copy + Clone {
|
|
type Subpixel: Primitive;
|
|
}
|
|
|
|
pub trait Primitive: Copy + PartialOrd<Self> + Clone {
|
|
}
|
|
|
|
impl<P, Container> GenericImage for ImageBuffer<P, Container>
|
|
where P: Pixel + 'static,
|
|
Container: Deref<Target=[P::Subpixel]> + DerefMut,
|
|
P::Subpixel: 'static {
|
|
|
|
type Pixel = P;
|
|
}
|
|
|
|
impl Primitive for u8 { }
|
|
|
|
impl<P, Container> ImageBuffer<P, Container>
|
|
where P: Pixel + 'static,
|
|
P::Subpixel: 'static,
|
|
Container: Deref<Target=[P::Subpixel]>
|
|
{
|
|
pub fn pixels<'a>(&'a self) -> Pixels<'a, Self> {
|
|
loop { }
|
|
}
|
|
|
|
pub fn pixels_mut(&mut self) -> PixelsMut<P> {
|
|
loop { }
|
|
}
|
|
}
|
|
|
|
pub struct Pixels<'a, I: 'a> {
|
|
image: &'a I,
|
|
x: u32,
|
|
y: u32,
|
|
width: u32,
|
|
height: u32
|
|
}
|
|
|
|
impl<'a, I: GenericImage> Iterator for Pixels<'a, I> {
|
|
type Item = (u32, u32, I::Pixel);
|
|
|
|
fn next(&mut self) -> Option<(u32, u32, I::Pixel)> {
|
|
loop { }
|
|
}
|
|
}
|
|
|
|
pub struct PixelsMut<'a, P: Pixel + 'a> where P::Subpixel: 'a {
|
|
chunks: &'a mut P::Subpixel
|
|
}
|
|
|
|
impl<'a, P: Pixel + 'a> Iterator for PixelsMut<'a, P> where P::Subpixel: 'a {
|
|
type Item = &'a mut P;
|
|
|
|
fn next(&mut self) -> Option<&'a mut P> {
|
|
loop { }
|
|
}
|
|
}
|
|
|
|
pub fn index_colors<Pix>(image: &ImageBuffer<Pix, Vec<u8>>)
|
|
-> ImageBuffer<Luma<u8>, Vec<u8>>
|
|
where Pix: Pixel<Subpixel=u8> + 'static,
|
|
{
|
|
// When NLL-enabled, `let mut` below is deemed unnecessary (due to
|
|
// the remaining code being unreachable); so ignore that lint.
|
|
#![allow(unused_mut)]
|
|
|
|
let mut indices: ImageBuffer<_,Vec<_>> = loop { };
|
|
for (pixel, idx) in image.pixels().zip(indices.pixels_mut()) {
|
|
// failured occurred here ^^ because we were requiring that we
|
|
// could project Pixel or Subpixel from `T_indices` (type of
|
|
// `indices`), but the type is insufficiently constrained
|
|
// until we reach the return below.
|
|
}
|
|
indices
|
|
}
|
|
|
|
fn main() { }
|