tsigtypeop.nim works again

compiler/semtypes.nim

@@ -1193,7 +1193,7 @@ proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
       result = typeExpr.typ.base
       if result.isMetaType:
         var preprocessed = semGenericStmt(c, n)
-        result = makeTypeFromExpr(c, preprocessed)
+        result = makeTypeFromExpr(c, preprocessed.copyTree)
   of nkIdent, nkAccQuoted:
     var s = semTypeIdent(c, n)
     if s.typ == nil: 

compiler/semtypinst.nim

@@ -369,6 +369,7 @@ proc replaceTypeVarsTAux(cl: var TReplTypeVars, t: PType): PType =
 
   of tyFromExpr:
     if cl.allowMetaTypes: return
+    assert t.n.typ != t
     var n = prepareNode(cl, t.n)
     n = cl.c.semConstExpr(cl.c, n)
     if n.typ.kind == tyTypeDesc:

compiler/sigmatch.nim

@@ -1187,8 +1187,7 @@ proc paramTypesMatchAux(m: var TCandidate, f, argType: PType,
 
     if argType.kind == tyStatic:
       if m.callee.kind == tyGenericBody and tfGenericTypeParam notin argType.flags:
-        result = newNodeI(nkType, argOrig.info)
-        result.typ = makeTypeFromExpr(c, arg)
+        result = newNodeIT(nkType, argOrig.info, makeTypeFromExpr(c, arg))
         return
     else:
       var evaluated = c.semTryConstExpr(c, arg)