Fix up did_you_mean nastiness

Author: kddnewton

lib/syntax_tree/basic_visitor.rb

@@ -33,7 +33,11 @@ def corrections
           ).correct(visit_method)
       end
 
-      DidYouMean.correct_error(VisitMethodError, self)
+      # In some setups with Ruby you can turn off DidYouMean, so we're going to
+      # respect that setting here.
+      if defined?(DidYouMean) && DidYouMean.method_defined?(:correct_error)
+        DidYouMean.correct_error(VisitMethodError, self)
+      end
     end
 
     class << self

test/visitor_test.rb

@@ -40,9 +40,18 @@ def initialize
       end
     end
 
-    def test_visit_method_correction
-      error = assert_raises { Visitor.visit_method(:visit_binar) }
-      assert_match(/visit_binary/, error.message)
+    if defined?(DidYouMean) && DidYouMean.method_defined?(:correct_error)
+      def test_visit_method_correction
+        error = assert_raises { Visitor.visit_method(:visit_binar) }
+        message =
+          if Exception.method_defined?(:detailed_message)
+            error.detailed_message
+          else
+            error.message
+          end
+
+        assert_match(/visit_binary/, message)
+      end
     end
   end
 end