Add rustdoc test to check duplicated bounds with parents

Author: GuillaumeGomez

src/test/rustdoc/bounds-parent-child-duplicates.rs

@@ -0,0 +1,43 @@
+// This test ensures that if a child item's bounds are duplicated with the parent, they are not
+// generated in the documentation.
+
+#![crate_name = "foo"]
+
+pub trait Bar {}
+pub trait Bar2 {}
+pub trait Bar3 {}
+pub trait Bar4 {}
+
+// @has 'foo/trait.Foo.html'
+pub trait Foo<'a, T: Bar + 'a> where T: Bar2 {
+    // @has - '//*[@id="method.foo"]/h4' 'fn foo()'
+    // `Bar` shouldn't appear in the bounds.
+    // @!has - '//*[@id="method.foo"]/h4' 'Bar'
+    fn foo() where T: Bar {}
+    // @has - '//*[@id="method.foo2"]/h4' 'fn foo2()'
+    // `Bar2` shouldn't appear in the bounds.
+    // @!has - '//*[@id="method.foo2"]/h4' 'Bar2'
+    fn foo2() where T: Bar2 {}
+    // @has - '//*[@id="method.foo3"]/h4' "fn foo3<'b>()where T: Bar3, 'a: 'b,"
+    fn foo3<'b>() where T: Bar3, 'a: 'b {}
+    // @has - '//*[@id="method.foo4"]/h4' "fn foo4()where T: Bar3,"
+    fn foo4() where T: Bar2 + Bar3 {}
+}
+
+pub struct X;
+
+// @has 'foo/struct.X.html'
+impl<'a, T: Bar> X where T: Bar2 {
+    // @has - '//*[@id="method.foo"]/h4' 'fn foo()'
+    // @!has - '//*[@id="method.foo"]/h4' 'Bar'
+    // `Bar` shouldn't appear in the bounds.
+    pub fn foo() where T: Bar {}
+    // @has - '//*[@id="method.foo2"]/h4' 'fn foo2()'
+    // `Bar2` shouldn't appear in the bounds.
+    // @!has - '//*[@id="method.foo2"]/h4' 'Bar2'
+    pub fn foo2() where T: Bar2 {}
+    // @has - '//*[@id="method.foo3"]/h4' "fn foo3<'b>()where T: Bar3, 'a: 'b,"
+    pub fn foo3<'b>() where 'a: 'b, T: Bar3 {}
+    // @has - '//*[@id="method.foo4"]/h4' "fn foo4()where T: Bar3,"
+    pub fn foo4() where T: Bar2 + Bar3 {}
+}