Fix #18662 (#19534)

compiler/jsgen.nim

@@ -2796,7 +2796,9 @@ proc myClose(graph: ModuleGraph; b: PPassContext, n: PNode): PNode =
       var map: SourceMap
       (code, map) = genSourceMap($(code), outFile.string)
       writeFile(outFile.string & ".map", $(%map))
-    discard writeRopeIfNotEqual(code, outFile)
+    if not equalsFile(code, outFile):
+      if not writeRope(code, outFile):
+        rawMessage(m.config, errCannotOpenFile, outFile.string)
 
 
 proc myOpen(graph: ModuleGraph; s: PSym; idgen: IdGenerator): PPassContext =

compiler/ropes.nim

@@ -329,10 +329,3 @@ proc equalsFile*(r: Rope, filename: AbsoluteFile): bool =
   if result:
     result = equalsFile(r, f)
     close(f)
-
-proc writeRopeIfNotEqual*(r: Rope, filename: AbsoluteFile): bool =
-  # returns true if overwritten
-  if not equalsFile(r, filename):
-    result = writeRope(r, filename)
-  else:
-    result = false