Raise TypeError instead of ArgumentError when Array#fill's 3d argument length is not Number

Author: andrykonchin

spec/ruby/core/array/fill_spec.rb

@@ -205,6 +205,12 @@
     -> { [].fill('a', obj) }.should raise_error(TypeError)
   end
 
+  it "raises a TypeError when the length is not numeric" do
+    -> { [1, 2, 3].fill("x", 1, "foo") }.should raise_error(TypeError, /no implicit conversion of String into Integer/)
+    -> { [1, 2, 3].fill("x", 1, :"foo") }.should raise_error(TypeError, /no implicit conversion of Symbol into Integer/)
+    -> { [1, 2, 3].fill("x", 1, Object.new) }.should raise_error(TypeError, /no implicit conversion of Object into Integer/)
+  end
+
   not_supported_on :opal do
     it "raises an ArgumentError or RangeError for too-large sizes" do
       error_types = [RangeError, ArgumentError]

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

@@ -455,12 +455,7 @@ def fetch(idx, default=undefined)
       left = 0 if left < 0
 
       if !Primitive.undefined?(length) and length
-        begin
-          right = Primitive.rb_num2int length
-        rescue TypeError
-          raise ArgumentError, 'second argument must be an Integer'
-        end
-
+        right = Primitive.rb_num2int length
         return self if right == 0
         right += left
       else