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+A pattern binding is using the same name as one of the variants of a type.
+
+Erroneous code example:
+
+```compile_fail,E0170
+# #![deny(warnings)]
+enum Method {
+    GET,
+    POST,
+}
+
+fn is_empty(s: Method) -> bool {
+    match s {
+        GET => true,
+        _ => false
+    }
+}
+
+fn main() {}
+```
+
+Enum variants are qualified by default. For example, given this type:
+
+```
+enum Method {
+    GET,
+    POST,
+}
+```
+
+You would match it using:
+
+```
+enum Method {
+    GET,
+    POST,
+}
+
+let m = Method::GET;
+
+match m {
+    Method::GET => {},
+    Method::POST => {},
+}
+```
+
+If you don't qualify the names, the code will bind new variables named "GET" and
+"POST" instead. This behavior is likely not what you want, so `rustc` warns when
+that happens.
+
+Qualified names are good practice, and most code works well with them. But if
+you prefer them unqualified, you can import the variants into scope:
+
+```
+use Method::*;
+enum Method { GET, POST }
+# fn main() {}
+```
+
+If you want others to be able to import variants from your module directly, use
+`pub use`:
+
+```
+pub use Method::*;
+pub enum Method { GET, POST }
+# fn main() {}
+```