1 files changed, 7 insertions, 3 deletions
diff --git a/lib/pure/json.nim b/lib/pure/json.nim
index 85c3393b2..c831bf85d 100644
--- a/lib/pure/json.nim
+++ b/lib/pure/json.nim
@@ -437,7 +437,7 @@ macro `%*`*(x: untyped): untyped =
   ## `%` for every element.
   result = toJsonImpl(x)
 
-proc `==`*(a, b: JsonNode): bool =
+proc `==`*(a, b: JsonNode): bool {.noSideEffect.} =
   ## Check two nodes for equality
   if a.isNil:
     if b.isNil: return true
@@ -464,12 +464,16 @@ proc `==`*(a, b: JsonNode): bool =
       if a.fields.len != b.fields.len: return false
       for key, val in a.fields:
         if not b.fields.hasKey(key): return false
-        if b.fields[key] != val: return false
+        when defined(nimHasEffectsOf):
+          {.noSideEffect.}:
+            if b.fields[key] != val: return false
+        else:
+          if b.fields[key] != val: return false
       result = true
 
 proc hash*(n: OrderedTable[string, JsonNode]): Hash {.noSideEffect.}
 
-proc hash*(n: JsonNode): Hash =
+proc hash*(n: JsonNode): Hash {.noSideEffect.} =
   ## Compute the hash for a JSON node
   case n.kind
   of JArray: