fix #16458; make useNimRtl compile for --gc:orc (#19512)

* fix #16458; make useNimRtl compile for --gc:orc/arc

* fix tests

lib/system/mmdisp.nim

@@ -82,8 +82,9 @@ else:
     # XXX due to bootstrapping reasons, we cannot use  compileOption("gc", "stack") here
     include "system/gc_regions"
   elif defined(nimV2) or usesDestructors:
-    var allocator {.rtlThreadVar.}: MemRegion
-    instantiateForRegion(allocator)
+    when not defined(useNimRtl):
+      var allocator {.rtlThreadVar.}: MemRegion
+      instantiateForRegion(allocator)
     when defined(gcHooks):
       include "system/gc_hooks"
   elif defined(gcMarkAndSweep):

lib/system/orc.nim

@@ -119,7 +119,7 @@ template orcAssert(cond, msg) =
 when logOrc:
   proc strstr(s, sub: cstring): cstring {.header: "<string.h>", importc.}
 
-proc nimTraceRef(q: pointer; desc: PNimTypeV2; env: pointer) {.compilerRtl, inline.} =
+proc nimTraceRef(q: pointer; desc: PNimTypeV2; env: pointer) {.compilerRtl, inl.} =
   let p = cast[ptr pointer](q)
   if p[] != nil:
 
@@ -128,7 +128,7 @@ proc nimTraceRef(q: pointer; desc: PNimTypeV2; env: pointer) {.compilerRtl, inli
     var j = cast[ptr GcEnv](env)
     j.traceStack.add(p, desc)
 
-proc nimTraceRefDyn(q: pointer; env: pointer) {.compilerRtl, inline.} =
+proc nimTraceRefDyn(q: pointer; env: pointer) {.compilerRtl, inl.} =
   let p = cast[ptr pointer](q)
   if p[] != nil:
     var j = cast[ptr GcEnv](env)

lib/system/seqs_v2.nim

@@ -75,7 +75,8 @@ proc prepareSeqAdd(len: int; p: pointer; addlen, elemSize, elemAlign: int): poin
 
 proc shrink*[T](x: var seq[T]; newLen: Natural) {.tags: [], raises: [].} =
   when nimvm:
-    setLen(x, newLen)
+    {.cast(tags: []).}:
+      setLen(x, newLen)
   else:
     #sysAssert newLen <= x.len, "invalid newLen parameter for 'shrink'"
     when not supportsCopyMem(T):

tests/arc/t16458.nim

@@ -0,0 +1,6 @@
+discard """
+  matrix: "--gc:orc --d:useNimRtl"
+  action: "compile"
+"""
+
+echo 134