diff --git a/compiler/sigmatch.nim b/compiler/sigmatch.nim
index 544011f2d..00802e69b 100644
--- a/compiler/sigmatch.nim
+++ b/compiler/sigmatch.nim
@@ -418,7 +418,8 @@ proc procTypeRel(c: var TCandidate, f, a: PType): TTypeRelation =
 
     if tfNoSideEffect in f.flags and tfNoSideEffect notin a.flags:
       return isNone
-    elif tfThread in f.flags and a.flags * {tfThread, tfNoSideEffect} == {}:
+    elif tfThread in f.flags and a.flags * {tfThread, tfNoSideEffect} == {} and
+        optThreadAnalysis in gGlobalOptions:
       # noSideEffect implies ``tfThread``!
       return isNone
     elif f.flags * {tfIterator} != a.flags * {tfIterator}: