diff --git a/stdlib/internal/format.codon b/stdlib/internal/format.codon
index c7fb1769..145ac1ee 100644
--- a/stdlib/internal/format.codon
+++ b/stdlib/internal/format.codon
@@ -8,7 +8,7 @@ class int:
     def __format__(self, format_spec: str) -> str:
         err = False
         ret = _C.seq_str_int(self, format_spec, __ptr__(err))
-        if err:
+        if format_spec and err:
             _format_error(ret)
         return ret
 
@@ -17,7 +17,7 @@ class Int:
     def __format__(self, format_spec: str) -> str:
         err = False
         ret = _C.seq_str_int(self.__int__(), format_spec, __ptr__(err))
-        if err:
+        if format_spec and err:
             _format_error(ret)
         return ret
 
@@ -26,7 +26,7 @@ class UInt:
     def __format__(self, format_spec: str) -> str:
         err = False
         ret = _C.seq_str_uint(self.__int__(), format_spec, __ptr__(err))
-        if err:
+        if format_spec and err:
             _format_error(ret)
         return ret
 
@@ -35,7 +35,7 @@ class float:
     def __format__(self, format_spec: str) -> str:
         err = False
         ret = _C.seq_str_float(self, format_spec, __ptr__(err))
-        if err:
+        if format_spec and err:
             _format_error(ret)
         return ret if ret != "-nan" else "nan"
 
@@ -44,7 +44,7 @@ class str:
     def __format__(self, format_spec: str) -> str:
         err = False
         ret = _C.seq_str_str(self, format_spec, __ptr__(err))
-        if err:
+        if format_spec and err:
             _format_error(ret)
         return ret
 
@@ -53,6 +53,6 @@ class Ptr:
     def __format__(self, format_spec: str) -> str:
         err = False
         ret = _C.seq_str_ptr(self.as_byte(), format_spec, __ptr__(err))
-        if err:
+        if format_spec and err:
             _format_error(ret)
         return ret