4 files changed, 11 insertions, 0 deletions
diff --git a/lib/std/jsbigints.nim b/lib/std/jsbigints.nim
index 27df8fdad..04578fc87 100644
--- a/lib/std/jsbigints.nim
+++ b/lib/std/jsbigints.nim
@@ -3,6 +3,9 @@
 when not defined(js):
   {.fatal: "Module jsbigints is designed to be used with the JavaScript backend.".}
 
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
 type JsBigIntImpl {.importjs: "bigint".} = int # https://github.com/nim-lang/Nim/pull/16606
 type JsBigInt* = distinct JsBigIntImpl         ## Arbitrary precision integer for JavaScript target.
 
diff --git a/lib/std/sysrand.nim b/lib/std/sysrand.nim
index 4ee25d01e..ff62c920b 100644
--- a/lib/std/sysrand.nim
+++ b/lib/std/sysrand.nim
@@ -62,6 +62,9 @@ when not defined(js):
 when defined(posix):
   import posix
 
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
 const
   batchImplOS = defined(freebsd) or defined(openbsd) or defined(zephyr) or (defined(macosx) and not defined(ios))
   batchSize {.used.} = 256
diff --git a/lib/std/tasks.nim b/lib/std/tasks.nim
index 7b931ab14..ac35e26bf 100644
--- a/lib/std/tasks.nim
+++ b/lib/std/tasks.nim
@@ -13,6 +13,9 @@
 import std/[macros, isolation, typetraits]
 import system/ansi_c
 
+when defined(nimPreviewSlimSystem):
+  import std/assertions
+
 export isolation
 
 
diff --git a/lib/std/tempfiles.nim b/lib/std/tempfiles.nim
index ce84c2a37..ee42f8a5c 100644
--- a/lib/std/tempfiles.nim
+++ b/lib/std/tempfiles.nim
@@ -19,6 +19,8 @@ See also:
 
 import os, random
 
+when defined(nimPreviewSlimSystem):
+  import std/syncio
 
 const
   maxRetry = 10000