1 files changed, 104 insertions, 0 deletions
diff --git a/src/test/ui/associated-types/project-defer-unification.rs b/src/test/ui/associated-types/project-defer-unification.rs
new file mode 100644
index 000000000..547ff45c2
--- /dev/null
+++ b/src/test/ui/associated-types/project-defer-unification.rs
@@ -0,0 +1,104 @@
+// 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() { }