restore does-nothing

src/tools/tidy/src/ui_tests.rs

@@ -18,7 +18,7 @@ const ENTRY_LIMIT: usize = 900;
 // FIXME: The following limits should be reduced eventually.
 
 const ISSUES_ENTRY_LIMIT: usize = 1733;
-const ROOT_ENTRY_LIMIT: usize = 859;
+const ROOT_ENTRY_LIMIT: usize = 861;
 
 const EXPECTED_TEST_FILE_EXTENSIONS: &[&str] = &[
     "rs",     // test source files

tests/ui/does-nothing.rs

@@ -0,0 +1,2 @@
+fn main() { println!("doing"); this_does_nothing_what_the; println!("boing"); }
+//~^ ERROR cannot find value `this_does_nothing_what_the` in this scope

tests/ui/does-nothing.stderr

@@ -0,0 +1,9 @@
+error[E0425]: cannot find value `this_does_nothing_what_the` in this scope
+  --> $DIR/does-nothing.rs:1:32
+   |
+LL | fn main() { println!("doing"); this_does_nothing_what_the; println!("boing"); }
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0425`.