Use `Primitive.mandatory_only?` for `Time.at`

2 files changed, 11 insertions, 1 deletions

diff --git a/time.c b/time.c
index 44864ff748..9c23089cfd 100644
--- a/time.c
+++ b/time.c
@@ -2708,6 +2708,12 @@ time_s_at(rb_execution_context_t *ec, VALUE klass, VALUE time, VALUE subsec, VAL
     return t;
 }
 
+static VALUE
+time_s_at1(rb_execution_context_t *ec, VALUE klass, VALUE time)
+{
+    return time_s_at(ec, klass, time, Qfalse, ID2SYM(id_microsecond), Qnil);
+}
+
 static const char months[][4] = {
     "jan", "feb", "mar", "apr", "may", "jun",
     "jul", "aug", "sep", "oct", "nov", "dec",
diff --git a/timev.rb b/timev.rb
index a475fc482d..675b54faf6 100644
--- a/timev.rb
+++ b/timev.rb
@@ -268,7 +268,11 @@ class Time
   # :include: doc/time/in.rdoc
   #
   def self.at(time, subsec = false, unit = :microsecond, in: nil)
-    Primitive.time_s_at(time, subsec, unit, Primitive.arg!(:in))
+    if Primitive.mandatory_only?
+      Primitive.time_s_at1(time)
+    else
+      Primitive.time_s_at(time, subsec, unit, Primitive.arg!(:in))
+    end
   end
 
   # Returns a new \Time object based the on given arguments.