diff --git a/spec/core/range/size_spec.rb b/spec/core/range/size_spec.rb
index 379939891c..a1fe3ce17d 100644
--- a/spec/core/range/size_spec.rb
+++ b/spec/core/range/size_spec.rb
@@ -76,23 +76,21 @@
 
   ruby_version_is "3.4" do
     it 'raises TypeError if a range is not iterable' do
-      NATFIXME 'it raises TypeError if a range is not iterable' do
-        -> { (1.0..16.0).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (1.0...16.0).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (1.0..15.9).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (1.1..16.0).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (1.1..15.9).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (16.0..0.0).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (Float::INFINITY..0).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (-Float::INFINITY..0).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (-Float::INFINITY..Float::INFINITY).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (..1).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (...0.5).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (..nil).size }.should raise_error(TypeError, /can't iterate from/)
-        -> { (...'o').size }.should raise_error(TypeError, /can't iterate from/)
-        -> { eval("(0.5...)").size }.should raise_error(TypeError, /can't iterate from/)
-        -> { eval("([]...)").size }.should raise_error(TypeError, /can't iterate from/)
-      end
+      -> { (1.0..16.0).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (1.0...16.0).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (1.0..15.9).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (1.1..16.0).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (1.1..15.9).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (16.0..0.0).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (Float::INFINITY..0).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (-Float::INFINITY..0).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (-Float::INFINITY..Float::INFINITY).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (..1).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (...0.5).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (..nil).size }.should raise_error(TypeError, /can't iterate from/)
+      -> { (...'o').size }.should raise_error(TypeError, /can't iterate from/)
+      -> { eval("(0.5...)").size }.should raise_error(TypeError, /can't iterate from/)
+      -> { eval("([]...)").size }.should raise_error(TypeError, /can't iterate from/)
     end
   end
 
diff --git a/src/match_data_object.cpp b/src/match_data_object.cpp
index 397a75795b..b4ae59a1b8 100644
--- a/src/match_data_object.cpp
+++ b/src/match_data_object.cpp
@@ -344,10 +344,12 @@ ArrayObject *MatchDataObject::values_at(Env *env, Args &&args) {
                 env->raise("RangeError", "{} out of range", range->inspect_str(env));
             auto append = ref(env, range);
             result->concat(env, { append });
-            auto size = range->send(env, "size"_s);
-            if (append->is_array() && size->is_integer() && size->as_integer()->to_nat_int_t() > static_cast<nat_int_t>(append->as_array()->size())) {
-                for (nat_int_t i = append->as_array()->size(); i < size->as_integer()->to_nat_int_t(); i++)
-                    result->push(NilObject::the());
+            if (range->begin()->is_integer()) {
+                auto size = range->send(env, "size"_s);
+                if (append->is_array() && size->is_integer() && size->as_integer()->to_nat_int_t() > static_cast<nat_int_t>(append->as_array()->size())) {
+                    for (nat_int_t i = append->as_array()->size(); i < size->as_integer()->to_nat_int_t(); i++)
+                        result->push(NilObject::the());
+                }
             }
         } else {
             result->push(ref(env, key));
diff --git a/src/range.rb b/src/range.rb
index 85d7fc36d7..b6aba79695 100644
--- a/src/range.rb
+++ b/src/range.rb
@@ -122,23 +122,21 @@ def minmax(&block)
   end
 
   def size
+    raise TypeError, "can't iterate from #{self.begin.class}" unless self.begin.respond_to?(:succ)
     return if self.begin.nil? && !self.end.is_a?(Numeric)
-    return Float::INFINITY if self.begin.nil?
     return unless self.begin.is_a?(Numeric)
     return Float::INFINITY if self.end.nil?
-    return unless self.end.is_a?(Numeric)
     return 0 if self.end < self.begin
-    return Float::INFINITY if self.begin.is_a?(Float) && self.begin.infinite?
     return Float::INFINITY if self.end.is_a?(Float) && self.end.infinite?
     size = self.end - self.begin
     size += 1 unless exclude_end?
-    return size.floor if size.is_a?(Float)
     size
   end
 
   def reverse_each
     raise TypeError, "can't iterate from #{self.end.class}" if self.end.nil?
     return super unless self.end.respond_to?(:pred)
+    size = self.begin.nil? ? Float::INFINITY : self.size
     return enum_for(:reverse_each) { size } unless block_given?
     item = self.end
     item = item.pred if exclude_end?