add tests for doc coverage

src/test/rustdoc-ui/coverage/basic.rs

@@ -0,0 +1,50 @@
+// compile-flags:-Z unstable-options --show-coverage
+// compile-pass
+
+#![feature(extern_types)]
+
+//! Make sure to have some docs on your crate root
+
+/// This struct is documented, but its fields are not.
+///
+/// However, one field is private, so it shouldn't show in the total.
+pub struct SomeStruct {
+    pub some_field: usize,
+    other_field: usize,
+}
+
+impl SomeStruct {
+    /// Method with docs
+    pub fn this_fn(&self) {}
+
+    // Method without docs
+    pub fn other_method(&self) {}
+}
+
+// struct without docs
+pub struct OtherStruct;
+
+// function with no docs
+pub fn some_fn() {}
+
+/// Function with docs
+pub fn other_fn() {}
+
+pub enum SomeEnum {
+    /// Some of these variants are documented...
+    VarOne,
+    /// ...but some of them are not.
+    VarTwo,
+    // (like this one)
+    VarThree,
+}
+
+/// There's a macro here, too
+#[macro_export]
+macro_rules! some_macro {
+    () => {};
+}
+
+extern {
+    pub type ExternType;
+}