GitBranch.equals(): simplify, allow subclasses, add null-check to the super.equals

plugins/git4idea/src/git4idea/GitBranch.java

@@ -109,9 +109,9 @@ public class GitBranch extends GitReference {
 
   @Override
   public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-    if (!super.equals(o)) return false;
+    if (!super.equals(o)) {
+      return false;
+    }
 
     // Reusing equals from super: only the name is important:
     // branches are considered equal even if they point to different commits.

plugins/git4idea/src/git4idea/GitReference.java

@@ -50,6 +50,10 @@ public abstract class GitReference implements Comparable<GitReference> {
 
   @Override
   public boolean equals(Object obj) {
+    if (this == obj) {
+      return true;
+    }
+
     return obj instanceof GitReference && getFullName().equals(((GitReference)obj).getFullName());
   }