1 files changed, 62 insertions, 0 deletions
diff --git a/src/test/ui/traits/inheritance/self-in-supertype.rs b/src/test/ui/traits/inheritance/self-in-supertype.rs
new file mode 100644
index 000000000..e8a2bd791
--- /dev/null
+++ b/src/test/ui/traits/inheritance/self-in-supertype.rs
@@ -0,0 +1,62 @@
+// run-pass
+// Test for issue #4183: use of Self in supertraits.
+
+pub static FUZZY_EPSILON: f64 = 0.1;
+
+pub trait FuzzyEq<Eps> {
+    fn fuzzy_eq(&self, other: &Self) -> bool;
+    fn fuzzy_eq_eps(&self, other: &Self, epsilon: &Eps) -> bool;
+}
+
+trait Float: Sized+FuzzyEq<Self> {
+    fn two_pi() -> Self;
+}
+
+impl FuzzyEq<f32> for f32 {
+    fn fuzzy_eq(&self, other: &f32) -> bool {
+        self.fuzzy_eq_eps(other, &(FUZZY_EPSILON as f32))
+    }
+
+    fn fuzzy_eq_eps(&self, other: &f32, epsilon: &f32) -> bool {
+        (*self - *other).abs() < *epsilon
+    }
+}
+
+impl Float for f32 {
+    fn two_pi() -> f32 { 6.28318530717958647692528676655900576_f32 }
+}
+
+impl FuzzyEq<f64> for f64 {
+    fn fuzzy_eq(&self, other: &f64) -> bool {
+        self.fuzzy_eq_eps(other, &(FUZZY_EPSILON as f64))
+    }
+
+    fn fuzzy_eq_eps(&self, other: &f64, epsilon: &f64) -> bool {
+        (*self - *other).abs() < *epsilon
+    }
+}
+
+impl Float for f64 {
+    fn two_pi() -> f64 { 6.28318530717958647692528676655900576_f64 }
+}
+
+fn compare<F:Float>(f1: F) -> bool {
+    let f2 = Float::two_pi();
+    f1.fuzzy_eq(&f2)
+}
+
+pub fn main() {
+    assert!(compare::<f32>(6.28318530717958647692528676655900576));
+    assert!(compare::<f32>(6.29));
+    assert!(compare::<f32>(6.3));
+    assert!(compare::<f32>(6.19));
+    assert!(!compare::<f32>(7.28318530717958647692528676655900576));
+    assert!(!compare::<f32>(6.18));
+
+    assert!(compare::<f64>(6.28318530717958647692528676655900576));
+    assert!(compare::<f64>(6.29));
+    assert!(compare::<f64>(6.3));
+    assert!(compare::<f64>(6.19));
+    assert!(!compare::<f64>(7.28318530717958647692528676655900576));
+    assert!(!compare::<f64>(6.18));
+}