Add invalid rust code for test

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

@@ -0,0 +1,12 @@
+// check-pass
+// compile-flags:--test -Zunstable-options --nocapture
+// normalize-stderr-test: "src/test/rustdoc-ui" -> "$$DIR"
+// normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
+// normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
+
+/// ```compile_fail
+/// fn foo() {
+///     Input: 123
+/// }
+/// ```
+pub struct Foo;

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

@@ -0,0 +1,18 @@
+error: struct literal body without path
+  --> $DIR/nocapture-fail.rs:8:10
+   |
+LL |   fn foo() {
+   |  __________^
+LL | |     Input: 123
+LL | | }
+   | |_^
+   |
+help: you might have forgotten to add the struct literal inside the block
+   |
+LL | fn foo() { SomeStruct {
+LL |     Input: 123
+LL | } }
+   |
+
+error: aborting due to previous error
+

src/test/rustdoc-ui/nocapture-fail.stdout

@@ -0,0 +1,6 @@
+
+running 1 test
+test $DIR/nocapture-fail.rs - Foo (line 7) - compile fail ... ok
+
+test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+