more checking for --gc:arc, no need for valgrind (#14467)

* sigmatch: removed dead code

compiler/cgen.nim

@@ -2067,7 +2067,8 @@ proc myClose(graph: ModuleGraph; b: PPassContext, n: PNode): PNode =
       let disp = generateMethodDispatchers(graph)
       for x in disp: genProcAux(m, x.sym)
 
-  m.g.modulesClosed.add m
+  let mm = m
+  m.g.modulesClosed.add mm
 
 proc genForwardedProcs(g: BModuleList) =
   # Forward declared proc:s lack bodies when first encountered, so they're given

compiler/dfa.nim

@@ -809,4 +809,7 @@ proc constructCfg*(s: PSym; body: PNode): ControlFlowGraph =
   withBlock(s):
     gen(c, body)
     genImplicitReturn(c)
-  shallowCopy(result, c.code)
+  when defined(gcArc) or defined(gcOrc):
+    result = c.code # will move
+  else:
+    shallowCopy(result, c.code)

compiler/injectdestructors.nim

@@ -354,6 +354,8 @@ proc genWasMoved(n: PNode; c: var Con): PNode =
   result = newNodeI(nkCall, n.info)
   result.add(newSymNode(createMagic(c.graph, "wasMoved", mWasMoved)))
   result.add copyTree(n) #mWasMoved does not take the address
+  #if n.kind != nkSym:
+  #  message(c.graph.config, n.info, warnUser, "wasMoved(" & $n & ")")
 
 proc genDefaultCall(t: PType; c: Con; info: TLineInfo): PNode =
   result = newNodeI(nkCall, info)

compiler/sigmatch.nim

@@ -993,6 +993,11 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
   result = isNone
   assert(f != nil)
 
+  when declared(deallocatedRefId):
+    let corrupt = deallocatedRefId(cast[pointer](f))
+    if corrupt != 0:
+      quit "it's corrupt " & $corrupt
+
   if f.kind == tyUntyped:
     if aOrig != nil: put(c, f, aOrig)
     return isGeneric
@@ -1409,7 +1414,6 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
     let roota = a.skipGenericAlias
     let rootf = f.skipGenericAlias
 
-    var m = c
     if a.kind == tyGenericInst:
       if roota.base == rootf.base:
         let nextFlags = flags + {trNoCovariance}