Raise Liquid::SyntaxError instead of NoMethodError for invalid range (#1607)

lib/liquid/range_lookup.rb

@@ -8,7 +8,17 @@ module Liquid
       if start_obj.respond_to?(:evaluate) || end_obj.respond_to?(:evaluate)
         new(start_obj, end_obj)
       else
-        start_obj.to_i..end_obj.to_i
+        begin
+          start_obj.to_i..end_obj.to_i
+        rescue NoMethodError
+          invalid_expr = start_markup unless start_obj.respond_to?(:to_i)
+          invalid_expr ||= end_markup unless end_obj.respond_to?(:to_i)
+          if invalid_expr
+            raise Liquid::SyntaxError, "Invalid expression type '#{invalid_expr}' in range expression"
+          end
+
+          raise
+        end
       end
     end
 

test/integration/expression_test.rb

@@ -29,6 +29,11 @@ class ExpressionTest < Minitest::Test
   def test_range
     assert_equal(1..2, parse_and_eval("(1..2)"))
     assert_equal(3..4, parse_and_eval(" ( 3 .. 4 ) "))
+
+    exc = assert_raises(Liquid::SyntaxError) { Liquid::Expression.parse("(false..true)") }
+    assert_equal("Liquid syntax error: Invalid expression type 'false' in range expression", exc.message)
+    exc = assert_raises(Liquid::SyntaxError) { Liquid::Expression.parse("((1..2)..3)") }
+    assert_equal("Liquid syntax error: Invalid expression type '(1..2)' in range expression", exc.message)
   end
 
   private