diff --git a/src/mfast/decimal_ref.h b/src/mfast/decimal_ref.h
--- a/src/mfast/decimal_ref.h
+++ b/src/mfast/decimal_ref.h
@@ -41,7 +41,7 @@
 
 inline decimal make_decimal(int64_t mantissa, int16_t exponent) {
   decimal r(mantissa);
-  r *= decimal_backend(1.0, exponent);
+  r *= decimal(decimal_backend(1.0, exponent));
   return r;
 }
 
@@ -119,7 +119,7 @@
 
   decimal value() const {
     decimal r(mantissa());
-    r *= decimal_backend(1.0, exponent());
+    r *= decimal(decimal_backend(1.0, exponent()));
     return r;
   }