Report use statements that use {} with only one entry

python/tidy/servo_tidy/tidy.py

@@ -390,6 +390,8 @@ def check_rust(file_name, lines):
             # No benefit over using &str
             (r": &String", "use &str instead of &String", no_filter),
             (r"^&&", "operators should go at the end of the first line", no_filter),
+            (r"\{[A-Za-z0-9_]+\};", "use statement contains braces for single import",
+                lambda match, line: line.startswith('use ')),
         ]
 
         for pattern, message, filter_func in regex_rules:

python/tidy/servo_tidy_tests/rust_tidy.rs

@@ -7,6 +7,7 @@ use azure::azure_hl::{AntialiasMode, Color,
 ColorPattern, CompositionOp};
 use euclid::size::Size2D;
 use azure::azure::AzIntSize;
+use azure::azure::{AzIntSize};
 
 use std;
 

python/tidy/servo_tidy_tests/test_tidy.py

@@ -53,6 +53,7 @@ class CheckTidiness(unittest.TestCase):
         self.assertEqual('use statement spans multiple lines', errors.next()[2])
         self.assertEqual('missing space before }', errors.next()[2])
         self.assertTrue('use statement is not in alphabetical order' in errors.next()[2])
+        self.assertEqual('use statement contains braces for single import', errors.next()[2])
         self.assertEqual('encountered whitespace following a use statement', errors.next()[2])
         self.assertTrue('mod declaration is not in alphabetical order' in errors.next()[2])
         self.assertEqual('mod declaration spans multiple lines', errors.next()[2])