[racerd] document GuardedBy issue

Summary: As per title

Reviewed By: jvillard

Differential Revision: D22019339

fbshipit-source-id: 0aab4475e

infer/documentation/issues/GUARDEDBY_VIOLATION.md

@@ -0,0 +1,16 @@
+A field annotated with `@GuardedBy` is being accessed by a call-chain that starts at a non-private method without synchronization.
+
+Example:
+
+```java
+class C {
+  @GuardedBy("this")
+  String f;
+
+  void foo(String s) {
+    f = s; // unprotected access here
+  }
+}
+```
+
+Action: Protect the offending access by acquiring the lock indicated by the `@GuardedBy(...)`.

infer/src/base/IssueType.ml

@@ -575,6 +575,7 @@ let _global_variable_initialized_with_function_or_method_call =
 
 let guardedby_violation_racerd =
   register_from_string Warning ~id:"GUARDEDBY_VIOLATION" ~hum:"GuardedBy Violation" RacerD
+    ~user_documentation:[%blob "../../documentation/issues/GUARDEDBY_VIOLATION.md"]
 
 
 let impure_function = register_from_string ~id:"IMPURE_FUNCTION" Error Impurity