Changes based on review.

Author: aardvark179

src/main/java/org/truffleruby/core/numeric/IntegerNodes.java

@@ -872,7 +872,7 @@ public Object compare(long a, Object b,
         @Specialization(guards = "!isRubyNumber(b)")
         public Object compare(DynamicObject a, Object b,
                 @Cached("createPrivate()") CallDispatchHeadNode redoCompare) {
-            return redoCompare.call(a, "redo_compare", coreStrings().SPACESHIP.getSymbol(), b);
+            return redoCompare.call(a, "redo_compare_no_error", b);
         }
 
     }

src/main/ruby/truffleruby/core/integer.rb

@@ -186,8 +186,8 @@ def round(ndigits=undefined, half: nil)
       if kind_of? Integer and f.kind_of? Integer
         x = self < 0 ? -self : self
         x = if (half == :down)
-              (x) / f
-            else
+              x / f
+            else # :up or nil
               (x + f / 2) / f
             end
         x = (x / 2) * 2 if half == :even

src/main/ruby/truffleruby/core/numeric.rb

@@ -241,7 +241,11 @@ def math_coerce(other, error=:coerce_error)
     values = other.coerce(self)
 
     unless Truffle::Type.object_kind_of?(values, Array) && values.length == 2
-      return nil
+      if error == :no_error
+        return nil
+      else
+        raise TypeError, 'coerce must return [x, y]'
+      end
     end
 
     [values[1], values[0]]