Add tests for rustdoc --check option

src/test/rustdoc-ui/check-fail.rs

@@ -0,0 +1,10 @@
+// compile-flags: -Z unstable-options --check
+
+#![deny(missing_docs)]
+//~^ ERROR
+//~^^ ERROR
+#![deny(rustdoc)]
+
+pub fn foo() {}
+//~^ ERROR
+//~^^ ERROR

src/test/rustdoc-ui/check-fail.stderr

@@ -0,0 +1,49 @@
+error: missing documentation for the crate
+  --> $DIR/check-fail.rs:3:1
+   |
+LL | / #![deny(missing_docs)]
+LL | |
+LL | |
+LL | | #![deny(rustdoc)]
+LL | |
+LL | | pub fn foo() {}
+   | |_______________^
+   |
+note: the lint level is defined here
+  --> $DIR/check-fail.rs:3:9
+   |
+LL | #![deny(missing_docs)]
+   |         ^^^^^^^^^^^^
+
+error: missing documentation for a function
+  --> $DIR/check-fail.rs:8:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^
+
+error: missing code example in this documentation
+  --> $DIR/check-fail.rs:3:1
+   |
+LL | / #![deny(missing_docs)]
+LL | |
+LL | |
+LL | | #![deny(rustdoc)]
+LL | |
+LL | | pub fn foo() {}
+   | |_______________^
+   |
+note: the lint level is defined here
+  --> $DIR/check-fail.rs:6:9
+   |
+LL | #![deny(rustdoc)]
+   |         ^^^^^^^
+   = note: `#[deny(missing_doc_code_examples)]` implied by `#[deny(rustdoc)]`
+
+error: missing code example in this documentation
+  --> $DIR/check-fail.rs:8:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+

src/test/rustdoc-ui/check.rs

@@ -0,0 +1,11 @@
+// check-pass
+// compile-flags: -Z unstable-options --check
+
+#![warn(missing_docs)]
+//~^ WARN
+//~^^ WARN
+#![warn(rustdoc)]
+
+pub fn foo() {}
+//~^ WARN
+//~^^ WARN

src/test/rustdoc-ui/check.stderr

@@ -0,0 +1,49 @@
+warning: missing documentation for the crate
+  --> $DIR/check.rs:4:1
+   |
+LL | / #![warn(missing_docs)]
+LL | |
+LL | |
+LL | | #![warn(rustdoc)]
+LL | |
+LL | | pub fn foo() {}
+   | |_______________^
+   |
+note: the lint level is defined here
+  --> $DIR/check.rs:4:9
+   |
+LL | #![warn(missing_docs)]
+   |         ^^^^^^^^^^^^
+
+warning: missing documentation for a function
+  --> $DIR/check.rs:9:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^
+
+warning: missing code example in this documentation
+  --> $DIR/check.rs:4:1
+   |
+LL | / #![warn(missing_docs)]
+LL | |
+LL | |
+LL | | #![warn(rustdoc)]
+LL | |
+LL | | pub fn foo() {}
+   | |_______________^
+   |
+note: the lint level is defined here
+  --> $DIR/check.rs:7:9
+   |
+LL | #![warn(rustdoc)]
+   |         ^^^^^^^
+   = note: `#[warn(missing_doc_code_examples)]` implied by `#[warn(rustdoc)]`
+
+warning: missing code example in this documentation
+  --> $DIR/check.rs:9:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^^^^
+
+warning: 4 warnings emitted
+

src/test/rustdoc/check.rs

@@ -0,0 +1,5 @@
+// compile-flags: -Z unstable-options --check
+
+// @!has check/fn.foo.html
+// @!has check/index.html
+pub fn foo() {}