---

yaml
---
r: 224225
b: refs/heads/beta
c: b531776
h: refs/heads/master
i:
  224223: 6d2fb50
v: v3

Author: Manishearth

[refs]

@@ -23,7 +23,7 @@ refs/tags/0.9: 36870b185fc5f5486636d4515f0e22677493f225
 refs/tags/0.10: ac33f2b15782272ae348dbd7b14b8257b2148b5a
 refs/tags/0.11.0: e1247cb1d0d681be034adb4b558b5a0c0d5720f9
 refs/tags/0.12.0: f0c419429ef30723ceaf6b42f9b5a2aeb5d2e2d1
-refs/heads/beta: dc556bef4313b59f082a1a0f7f2d30ef9cc88c0c
+refs/heads/beta: b5317761b8202affde7493d9b81a049b4727c29e
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: 938f5d7af401e2d8238522fed4a612943b6e77fd
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f

branches/beta/src/librustc/diagnostics.rs

@@ -1439,6 +1439,29 @@ anything, please remove the attribute or add some helpful note for users of the
 trait.
 "##,
 
+E0275: r##"
+This error occurs when there was a recursive trait requirement that overflowed
+before it could be evaluated. Often this means that there is unbounded recursion
+in resolving some type bounds.
+
+For example, in the following code
+
+```
+trait Foo {}
+
+struct Bar<T>(T);
+
+impl<T> Foo for T where Bar<T>: Foo {}
+```
+
+to determine if a `T` is `Foo`, we need to check if `Bar<T>` is `Foo`. However,
+to do this check, we need to determine that `Bar<Bar<T>>` is `Foo`. To determine
+this, we check if `Bar<Bar<Bar<T>>>` is `Foo`, and so on. This is clearly a
+recursive requirement that can't be resolved directly.
+
+Consider changing your trait bounds so that they're less self-referential.
+"##,
+
 E0277: r##"
 You tried to use a type which doesn't implement some trait in a place which
 expected that trait. Erroneous code example:
@@ -1863,7 +1886,6 @@ register_diagnostics! {
 //  E0134,
 //  E0135,
     E0264, // unknown external lang item
-    E0275, // overflow evaluating requirement
     E0276, // requirement appears on impl method but not on corresponding trait method
     E0278, // requirement is not satisfied
     E0279, // requirement is not satisfied