NULL_LITERAL expressions may always be null

there is no reason to give handlers a chance to override this because we
are also not doing this for other literals that we filter out at the
start of the method

nullaway/src/main/java/com/uber/nullaway/NullAway.java

@@ -23,11 +23,7 @@
 package com.uber.nullaway;
 
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
-import static com.sun.source.tree.Tree.Kind.EXPRESSION_STATEMENT;
-import static com.sun.source.tree.Tree.Kind.IDENTIFIER;
-import static com.sun.source.tree.Tree.Kind.OTHER;
-import static com.sun.source.tree.Tree.Kind.PARENTHESIZED;
-import static com.sun.source.tree.Tree.Kind.TYPE_CAST;
+import static com.sun.source.tree.Tree.Kind.*;
 import static com.uber.nullaway.ErrorBuilder.errMsgForInitializer;
 import static com.uber.nullaway.NullabilityUtil.castToNonNull;
 
@@ -2197,14 +2193,14 @@ private boolean mayBeNullExpr(VisitorState state, ExpressionTree expr) {
       // obviously not null
       return false;
     }
+    if (expr.getKind() == NULL_LITERAL) {
+      // obviously null, so same as for above literals we return early without consulting handlers
+      return true;
+    }
     // the logic here is to avoid doing dataflow analysis whenever possible
     Symbol exprSymbol = ASTHelpers.getSymbol(expr);
     boolean exprMayBeNull;
     switch (expr.getKind()) {
-      case NULL_LITERAL:
-        // obviously null
-        exprMayBeNull = true;
-        break;
       case ARRAY_ACCESS:
         // unsound!  we cannot check for nullness of array contents yet
         exprMayBeNull = false;