Add rustdoc test for bounds de-duplication and merge

Author: GuillaumeGomez

src/test/rustdoc/bounds-in-multiple-parts.rs

@@ -0,0 +1,20 @@
+#![crate_name = "foo"]
+
+pub trait Eq {}
+pub trait Eq2 {}
+
+// Checking that "where predicates" and "generics params" are merged.
+// @has 'foo/trait.T.html'
+// @has - "//*[@id='tymethod.f']/h4" "fn f<'a, 'b, 'c, T>()where Self: Eq, T: Eq + 'a, 'c: 'b + 'a,"
+pub trait T {
+    fn f<'a, 'b, 'c: 'a, T: Eq + 'a>()
+        where Self: Eq, Self: Eq, T: Eq, 'c: 'b;
+}
+
+// Checking that a duplicated "where predicate" is removed.
+// @has 'foo/trait.T2.html'
+// @has - "//*[@id='tymethod.f']/h4" "fn f<T>()where Self: Eq + Eq2, T: Eq2 + Eq,"
+pub trait T2 {
+    fn f<T: Eq>()
+        where Self: Eq, Self: Eq2, T: Eq2;
+}