diff --git a/lib/system.nim b/lib/system.nim
index da49386ed7..f8edca7602 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -2125,7 +2125,8 @@ elif hostOS != "standalone":
       inc(i)
   {.pop.}
 
-proc echo*[T](x: varargs[T, `$`]) {.magic: "Echo", tags: [WriteIOEffect], gcsafe.}
+proc echo*[T](x: varargs[T, `$`]) {.magic: "Echo", tags: [WriteIOEffect], gcsafe,
+                                    locks: 0.}
   ## Writes and flushes the parameters to the standard output.
   ##
   ## Special built-in that takes a variable number of arguments. Each argument
@@ -2141,7 +2142,7 @@ proc echo*[T](x: varargs[T, `$`]) {.magic: "Echo", tags: [WriteIOEffect], gcsafe
   ## instead.
 
 proc debugEcho*[T](x: varargs[T, `$`]) {.magic: "Echo", noSideEffect, 
-                                         tags: [], raises: [].}
+                                         tags: [], raises: [], locks: 0.}
   ## Same as `echo <#echo>`_, but as a special semantic rule, ``debugEcho``
   ## pretends to be free of side effects, so that it can be used for debugging
   ## routines marked as `noSideEffect <manual.html#nosideeffect-pragma>`_.