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