diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/Checker.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/check/Checker.rsc
index d3eeda94e39..98ec75730d4 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/Checker.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/Checker.rsc
@@ -183,7 +183,7 @@ ModuleStatus rascalTModelForLocs(
         mloc = mlocs[i];
         mname = mnames[i];
         if(isModuleLocationInLibs(mloc, pcfg)){
-            ms.status[mloc] ? {} += {rsc_not_found()};
+            ms = addProperty(mloc, ms, tpl_from_library());
         }
        
         ms.moduleLocs[mid] = mloc;
@@ -241,18 +241,15 @@ ModuleStatus rascalTModelForLocs(
             
             jobStep(jobName, intercalate(" + ", [*componentNames]), work=size(componentNames));
 
-            recheck = !all(m <- component, m in ms.status, (tpl_uptodate() in ms.status[m] || checked() in ms.status[m]));
+            recheck = !all(m <- component, hasAnyProperty(m, ms, tpl_uptodate(), checked()));
             for(m <- component){
                
-                if(m notin ms.status){
-                    ms.status[m] = {};
-                }
                 mi += 1;
                 if(!recheck){
-                    if(tpl_uptodate() notin ms.status[m]){
+                    if(hasNotProperty(m, ms, tpl_uptodate())){
                         <found, tm, ms> = getTModelForModule(m, ms);
                         if(found){
-                            ms.status[m] += {tpl_uptodate(), checked()};
+                            ms = addProperty(m, ms, tpl_uptodate(), checked());
                         }
                     }
                }
@@ -262,8 +259,7 @@ ModuleStatus rascalTModelForLocs(
             any_tpl_outdated = any(m <- component, tplOutdated(m, pcfg));
             if(any_tpl_outdated){
                 for(m <- component){
-                    ms.status[m] -= {tpl_uptodate(), checked()};
-                    ms.status[m] += {rsc_changed()};
+                    ms = deleteProperty(m, ms, tpl_uptodate(), checked());
                 }
             } else {
                 for(m <- component){
@@ -275,11 +271,11 @@ ModuleStatus rascalTModelForLocs(
                    
                             <m_compatible, ms> = importsAndExtendsAreBinaryCompatible(tm, imports_extends_m, ms);
                             if(m_compatible){
-                                ms.status[m] += {tpl_uptodate(), checked(), bom_update_needed()};
+                                ms = addProperty(m, ms, tpl_uptodate(), checked(), bom_update_needed());
                             }
                         }
                     } catch rascalTplVersionError(_,_,_,_): {
-                        ms.status[m] += { tpl_version_error() };
+                         ms = addProperty(m, ms, tpl_version_error());
                         // m_compatible remains false
                     };
                     
@@ -287,14 +283,15 @@ ModuleStatus rascalTModelForLocs(
                 }
             }
 
-            any_rsc_changed = any(m <- component, rsc_changed() in ms.status[m]);
-            any_from_lib = any(m <- component, rsc_not_found() in ms.status[m]);
+            any_rsc_changed = any(m <- component, hasProperty(m, ms, rsc_changed()));
+            all_rsc_found = all(m <- component, hasNotProperty(m, ms, rsc_not_found()));
+            any_from_lib = any(m <- component, hasProperty(m, ms, tpl_from_library()));
             all_tmodels_uptodate = true;
             for(m <- component){
-                if(tpl_uptodate() notin ms.status[m] && checked() notin ms.status[m])
+                if(hasNotProperty(m, ms, tpl_uptodate(), checked()))
                     all_tmodels_uptodate = false;
             }
-            recheckCond = !any_from_lib && (!compatible_with_all_imports || any_rsc_changed || !all_tmodels_uptodate);
+            recheckCond = !any_from_lib && all_rsc_found && (!compatible_with_all_imports || any_rsc_changed || !all_tmodels_uptodate);
 
              if(recheckCond){
                 // if(ms.compilerConfig.verbose){
@@ -306,16 +303,16 @@ ModuleStatus rascalTModelForLocs(
                 map[str,TModel] tmodels_for_component = ();
                 map[MODID,set[MODID]] m_imports = ();
                 map[MODID,set[MODID]] m_extends = ();
-                for(m <- component, rsc_not_found() notin ms.status[m], MStatus::ignored() notin ms.status[m]){
-                    imports =  { imp | <m1, importPath(), imp> <- ms.paths, m1 == m, MStatus::ignored() notin ms.status[imp]};
+                for(m <- component, hasNotProperty(m, ms, rsc_not_found(), ModuleProperty::ignored())){
+                    imports =  { imp | <m1, importPath(), imp> <- ms.paths, m1 == m, hasNotProperty(imp, ms, ModuleProperty::ignored())};
                     m_imports[m] =  imports;
-                    extends = { ext | <m1, extendPath(), ext > <- ms.paths, m1 == m, MStatus::ignored() notin ms.status[ext] };
+                    extends = { ext | <m1, extendPath(), ext > <- ms.paths, m1 == m, hasNotProperty(ext, ms, ModuleProperty::ignored()) };
                     m_extends[m] = extends;
                     invertedExtends = ms.paths<2,0>;
                     if(compilerConfig.warnUnused){
                         // Look for unused imports or extends
                         //usedModules = {path2module[l.path] | loc l <- range(tm.useDef), tm.definitions[l].idRole == moduleId(), path2module[l.path]?};
-                        usedModules = {l | loc l <- range(tm.useDef), tm.definitions[l].idRole == moduleId()};
+                        usedModules = {l | loc l <- range(tm.useDef), l in tm.definitions, tm.definitions[l].idRole == moduleId()};
                         usedModules += {*invertedExtends[um] | um <- usedModules}; // use of an extended module via import
                         list[Message] imsgs = [];
                         <success, pt, ms> = getModuleParseTree(m, ms);
@@ -327,10 +324,7 @@ ModuleStatus rascalTModelForLocs(
                             for(imod <- pt.header.imports, imod has \module){
                                 iname = unescape("<imod.\module.name>");
                                 inameId = moduleName2moduleId(iname);
-                                if(!ms.status[inameId]?){
-                                    ms.status[inameId] = {};
-                                }
-                                if({tpl_version_error(), rsc_not_found()} <= ms.status[inameId]){
+                                if(hasProperty(inameId, ms, tpl_version_error(), rsc_not_found())){
                                      imsgs += error("Rascal TPL version error for `<iname>`, no source found", imod@\loc);
                                 }
                                 if(inameId notin usedModules){
@@ -343,8 +337,8 @@ ModuleStatus rascalTModelForLocs(
                                    if(ms.moduleLocs[inameId]? && ms.moduleLocs[m]? && usesOrExtendsADT(ms.moduleLocs[m].path, ms.moduleLocs[inameId].path, tm)){
                                     continue check_imports;
                                    }
-                                   if((inameId in component || checked() in ms.status[inameId]) && rsc_not_found() notin ms.status[inameId]){
-                                       if(imod is \default){
+                                   if((inameId in component || hasProperty(inameId, ms, checked())) && hasNotProperty(inameId, ms, rsc_not_found())){
+                                    if(imod is \default){
                                          imsgs += warning("Unused import of `<iname>`", imod@\loc);
                                        } //else { //TODO: maybe add option to turn off info messages?
                                          //imsgs += info("Extended module `<iname>` is unused in the current module", imod@\loc);
@@ -360,9 +354,9 @@ ModuleStatus rascalTModelForLocs(
                     }
                     ms.messages[m] ? {} += toSet(tm.messages);
 
-                    ms.status[m] += {tpl_uptodate(), checked()};
+                    ms = addProperty(m, ms, tpl_uptodate(), checked());
                     if(errorsPresent(ms.messages[m])){
-                        ms.status[m]  += {check_error()};
+                        ms = addProperty(m, ms, check_error());
                     }
                 }
                 // prepare the TModels of the modules in this component for compilation
@@ -370,24 +364,19 @@ ModuleStatus rascalTModelForLocs(
                 <transient_tms, ms> = prepareForCompilation(component, m_imports, m_extends, ms, tm);
 
                 // generate code for the modules in this component
-
-                for(MODID m <- component, MStatus::ignored() notin ms.status[m]){
+                for(MODID m <- component, hasNotProperty(m, ms, ModuleProperty::ignored())){
                     <success, pt, ms> = getModuleParseTree(m, ms);
                     if(success){
                         lmsgs = codgen(m, pt, transient_tms, ms, compilerConfig);
                         ms.messages[m] += toSet(lmsgs);
-                        ms.status[m] += errorsPresent(lmsgs) ? {code_generation_error()} : {code_generated()};
+                        ms = addProperty(m, ms, errorsPresent(lmsgs) ? code_generation_error() : code_generated());
                     }
                 }
                 ms = doSaveModule(component, m_imports, m_extends, ms, transient_tms, compilerConfig);
                 for(m <- component){
-                    ms.status[m] -= {rsc_changed()};
-                    ms.status[m] += {tpl_uptodate()};
+                    ms = deleteProperty(m, ms, rsc_changed());
+                    ms = addProperty(m, ms, tpl_uptodate());
                 }
-            } else {
-                ;//  for(m <- component){  
-                //     ms.status[m] += bom_update_needed();
-                //  }
             }
         }
     } catch ParseError(loc src): {
@@ -433,7 +422,7 @@ tuple[set[MODID], ModuleStatus] loadImportsAndExtends(set[MODID] moduleIds, Modu
     pcfg = ms.pathConfig;
     for(<from, pathRole, imp> <- ms.paths, from in moduleIds){
         if(imp notin added, imp notin moduleIds){
-            if(tpl_uptodate() in ms.status[imp]){
+            if(hasProperty(imp, ms, tpl_uptodate())){
                 added += imp;
                 <found, tm, ms> = getTModelForModule(imp, ms);
                 try {
@@ -458,15 +447,16 @@ tuple[TModel, ModuleStatus] rascalTModelComponent(set[MODID] moduleIds, ModuleSt
     map[MODID, Module] idTrees = ();
     for(MODID mid <- moduleIds){
         mname = moduleId2moduleName(mid);
-        //ms.status[mid] = {};
-        //ms.messages[mid] = {};
         ms = removeTModel(mid, ms);
         mloc = |unknown:///|(0,0,<0,0>,<0,0>);
         try {
             mloc = getRascalModuleLocation(mid, ms);
+            if(endsWith(mloc.path, "tpl")){
+                ms = addProperty(mid, ms, tpl_from_library());
+            }
         } catch Message err: {
             ms.messages[mid] = { err };
-            ms.status[mid] += { rsc_not_found() };
+            ms = addProperty(mid, ms, rsc_not_found());
             tm = tmodel(modelName=mname, messages=[ err ]);
             ms = addTModel(mid, tm, ms);
             return <tm, ms>;
@@ -480,7 +470,7 @@ tuple[TModel, ModuleStatus] rascalTModelComponent(set[MODID] moduleIds, ModuleSt
 
             if(hasIgnoreCompilerTag(tagsMap)) {
                     ms.messages[mid] ? {} += { Message::info("Ignoring module <mid>", pt.header.name@\loc) };
-                    ms.status[mid] += MStatus::ignored();
+                    ms = addProperty(mid, ms, ModuleProperty::ignored());
             }
             idTrees[mid] = pt;
         }
@@ -522,8 +512,8 @@ tuple[TModel, ModuleStatus] rascalTModelComponent(set[MODID] moduleIds, ModuleSt
         return <tm, ms>;
     } else {
         oneOfComponent = getOneFrom(moduleIds);
-        ms.status[oneOfComponent]? {} += { tpl_saved() };            // TODO check this, when is this executed?
-        <found, tm, ms> = getTModelForModule(oneOfComponent, ms);
+        ms = addProperty(oneOfComponent, ms, tpl_saved());
+       <found, tm, ms> = getTModelForModule(oneOfComponent, ms);
         return <tm, ms>;
     }
 }
@@ -565,7 +555,7 @@ tuple[bool, ModuleStatus] libraryDependenciesAreCompatible(list[MODID] candidate
         try {
             <found, tm, ms> = getTModelForModule(candidate, ms);
             if(found){ // TODO: needed?
-                imports_and_extends = ms.paths<0,2>[candidate];
+                imports_and_extends = tm.paths<0,2>[candidate]; // ms.paths<0,2>[candidate];
                 <compatible, ms> = importsAndExtendsAreBinaryCompatible(tm, imports_and_extends, ms);
                 if(!compatible){
                     return <false, ms>;
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/CheckerCommon.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/check/CheckerCommon.rsc
index b8f89b62721..391ef186eef 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/CheckerCommon.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/CheckerCommon.rsc
@@ -68,14 +68,10 @@ void checkSupportedByParserGenerator(Tree t, Collector c){
     });
  }
 
-
-
-data MStatus =
+data ModuleProperty =
       rsc_not_found()
-    | tpl_not_found()
-    | tpl_version_error()
     | rsc_changed()
-    | parsed()
+    // | parsed()
     | parse_error()
     | module_dependencies_extracted()
     | checked()
@@ -83,7 +79,10 @@ data MStatus =
     | code_generated()
     | code_generation_error()
     | tpl_uptodate()
+    | tpl_from_library()
     | tpl_saved()
+    | tpl_not_found()
+    | tpl_version_error()
     | ignored()
     | bom_update_needed()
     ;
@@ -99,11 +98,46 @@ data ModuleStatus =
       map[MODID,loc] moduleLocs,
       map[MODID,datetime] moduleLastModified,
       map[MODID, set[Message]] messages,
-      map[MODID, set[MStatus]] status,
+      map[MODID, set[ModuleProperty]] status,
       PathConfig pathConfig,
       RascalCompilerConfig compilerConfig
    );
 
+// p1 in status && p2 in status ...
+bool hasProperty(MODID mid, ModuleStatus ms, ModuleProperty properties...){
+    if(mid notin ms.status) return false;
+    mstatus = ms.status[mid];
+    return !isEmpty(mstatus) && all(p <- properties, p in mstatus);
+}
+
+// p1 in status || p2 in status ...
+bool hasAnyProperty(MODID mid, ModuleStatus ms, ModuleProperty properties...){
+    if(mid notin ms.status) return false;
+    mstatus = ms.status[mid];
+    return !isEmpty(mstatus) && any(p <- properties, p in mstatus);
+}
+
+// p1 notin status && p2 notin status ...
+bool hasNotProperty(MODID mid, ModuleStatus ms, ModuleProperty properties...){
+    if(mid notin ms.status) return true;
+    mstatus = ms.status[mid];
+    return isEmpty(mstatus) || all(ModuleProperty p <- properties, p notin mstatus);
+}
+
+ModuleStatus addProperty(MODID mid, ModuleStatus ms, ModuleProperty properties...){
+    mstatus = mid notin ms.status ? {} : ms.status[mid];
+    mstatus += toSet(properties);
+    ms.status[mid] = mstatus;
+    return ms;
+}
+
+ModuleStatus deleteProperty(MODID mid, ModuleStatus ms, ModuleProperty properties...){
+    mstatus = mid notin ms.status ? {} : ms.status[mid];
+    mstatus -= toSet(properties);
+    ms.status[mid] = mstatus;
+    return ms;
+}
+
 ModuleStatus moduleStatus(          // TEMPORARY FOR COMPATIBILITY BETWEEN VERSIONS
       rel[str, PathRole, str] _strPaths,
       rel[MODID, PathRole, MODID] _paths,
@@ -115,7 +149,7 @@ ModuleStatus moduleStatus(          // TEMPORARY FOR COMPATIBILITY BETWEEN VERSI
       map[MODID,loc] _moduleLocs,
       map[MODID,datetime] _moduleLastModified,
       map[MODID, set[Message]] _messages,
-      map[MODID, set[MStatus]] _status,
+      map[MODID, set[ModuleProperty]] _status,
       PathConfig pathConfig,
       RascalCompilerConfig compilerConfig)
       = newModuleStatus(pathConfig, compilerConfig);
@@ -221,6 +255,7 @@ bool tplOutdated(MODID moduleId, PathConfig pcfg){
     try {
         qualifiedModuleName = moduleId2moduleName(moduleId);
         mloc = getRascalModuleLocation(qualifiedModuleName, pcfg);
+        if(endsWith(mloc.path, "tpl")) return false;
         <found, tpl> = getTPLReadLoc(qualifiedModuleName, pcfg);
         lmMloc = lastModified(mloc);
         lmTpl = lastModified(tpl);
@@ -244,10 +279,7 @@ tuple[bool, Module, ModuleStatus] getModuleParseTree(MODID moduleId, ModuleStatu
         if(traceParseTreeCache) println("*** using cached parse tree for <moduleId>");
         return <true, ms.parseTrees[moduleId], ms>;
     } else {
-        if(!ms.status[moduleId]?){
-            ms.status[moduleId] = {};
-        }
-        if(parse_error() notin ms.status[moduleId]){
+        if(hasNotProperty(moduleId, ms, parse_error())){
             if(size(ms.parseTreeLIFO) >= parseTreeCacheSize){
                 ms.parseTrees = delete(ms.parseTrees, ms.parseTreeLIFO[-1]);
                 if(traceParseTreeCache) println("*** deleting parse tree <ms.parseTreeLIFO[-1]>");
@@ -259,7 +291,7 @@ tuple[bool, Module, ModuleStatus] getModuleParseTree(MODID moduleId, ModuleStatu
                 mloc = getRascalModuleLocation(moduleId, ms);
                 // Make sure we found a real source module (as opposed to a tpl module in a library
                 if(isModuleLocationInLibs(mloc, pcfg)) {
-                    ms.status[moduleId] += {rsc_not_found()};
+                    ms = addProperty(moduleId, ms, tpl_from_library());
                     throw "No src or library module";
                 }
             } catch e: {
@@ -273,12 +305,11 @@ tuple[bool, Module, ModuleStatus] getModuleParseTree(MODID moduleId, ModuleStatu
                 ms.parseTrees[moduleId] = pt;
                 newLoc = getLoc(pt);
                 ms.moduleLocs[moduleId] = newLoc;
-                ms.status[moduleId] ? {} += {parsed()};
                 return <true, pt, ms>;
             } catch ParseError(loc src): {
                 ms.messages[moduleId] ? {} = {error("Parse error in <moduleId>", src)};
                 ms.moduleLocs[moduleId] = mloc;
-                ms.status[moduleId] += parse_error();
+                ms = addProperty(moduleId, ms, parse_error());
                 return <false, dummyModule, ms>;
             }
         }
@@ -307,14 +338,14 @@ loc getRascalModuleLocation(MODID moduleId, ModuleStatus ms){
 int tmodelCacheSize = 30; // should be > 0
 
 ModuleStatus clearTModelCache(ModuleStatus ms){
-    todo = { mname | mname <- ms.status, bom_update_needed() in ms.status[mname]};
+    todo = { mname | mname <- ms.status, hasProperty(mname, ms, bom_update_needed())};
     for(candidate <- ms.tmodelLIFO){
         ms = removeOldestTModelFromCache(ms/*, updateBOMneeded=true*/);
         todo -= candidate;
     }
     for(candidate <- todo){
         ms = removeTModel(candidate, ms/*, updateBOMneeded=true*/);
-        ms.status[candidate] -= bom_update_needed();
+        ms = deleteProperty(candidate, ms, bom_update_needed());
     }
     return ms;
 }
@@ -330,7 +361,7 @@ rel[str,datetime,PathRole] makeBom(MODID moduleId, ModuleStatus ms){
 }
 
 ModuleStatus updateBOM(MODID moduleId, ModuleStatus ms){
-    if(rsc_not_found() in ms.status[moduleId]){
+    if(hasAnyProperty(moduleId, ms, rsc_not_found(), tpl_from_library())){
         return ms;
     }
     <found, tm, ms> = getTModelForModule(moduleId, ms);
@@ -339,7 +370,7 @@ ModuleStatus updateBOM(MODID moduleId, ModuleStatus ms){
         newBom = makeBom(moduleId, ms);
         if(newBom != tm.store[key_bom]){
             tm.store[key_bom] = newBom;
-            ms.status[moduleId] -= {tpl_saved(), bom_update_needed()};
+            ms = deleteProperty(moduleId, ms, tpl_saved(), bom_update_needed());
             ms = addTModel(moduleId, tm, ms);
 
             if(ms.compilerConfig.logWrittenFiles) println("Updated BOM: <moduleId>");
@@ -353,20 +384,18 @@ ModuleStatus updateBOM(MODID moduleId, ModuleStatus ms){
 ModuleStatus removeTModel(MODID candidate, ModuleStatus ms, bool updateBOMneeded = false){
     assert isModuleId(candidate) : "removeTModel: <candidate>";
     if(   updateBOMneeded
-       || (   candidate in ms.tmodels 
-           && candidate in ms.status
-           && tpl_saved() notin ms.status[candidate] 
-           && rsc_not_found() notin ms.status[candidate])
+       ||    candidate in ms.tmodels 
+          && !hasAnyProperty(candidate, ms, tpl_saved(), rsc_not_found(), tpl_from_library())
       ){
         pcfg = ms.pathConfig;
         if(updateBOMneeded){
             ms = updateBOM(candidate, ms);
          } 
-        ms.status[candidate] -= bom_update_needed();
+         ms = deleteProperty(candidate, ms,  bom_update_needed());
         <found, tplLoc> = getTPLWriteLoc(candidate, pcfg);
         tm = ms.tmodels[candidate];
         //tm.messages = toList(toSet(tm.messages) + ms.messages[candidate]); // TODO needed ?
-        ms.status[candidate] += tpl_saved();
+        ms = addProperty(candidate, ms, tpl_saved());
         if(ms.compilerConfig.verbose) println("Saving tmodel for <moduleId2moduleName(candidate)> before removing from cache");
         try {
             writeBinaryValueFile(tplLoc, tm);
@@ -432,9 +461,9 @@ tuple[bool, TModel, ModuleStatus] getTModelForModule(MODID moduleId, ModuleStatu
                 ms.tmodels[moduleId] = tm;
                 mloc = getRascalModuleLocation(moduleId, ms);
                 if(isModuleLocationInLibs(mloc, pcfg)){
-                    ms.status[moduleId] ? {} += {rsc_not_found()};
+                    ms = addProperty(moduleId, ms, tpl_from_library());
                 }
-                ms.status[moduleId] ? {} += {tpl_uptodate(), tpl_saved()};
+                ms = addProperty(moduleId, ms, tpl_uptodate(), tpl_saved());
                 //do not include errors from tm in ModuleStatus to avoid that they become persistent
                 ms.tmodelLIFO = [moduleId, *ms.tmodelLIFO];
                 return <true, tm, ms>;
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/Import.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/check/Import.rsc
index 103f5c28c85..9c1e54df3f9 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/Import.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/Import.rsc
@@ -57,7 +57,7 @@ ModuleStatus reportSelfImport(rel[loc, PathRole, loc] paths, ModuleStatus ms){
     for(<from, importPath(), from> <- paths){
        // mname = getRascalModuleName(from, ms.pathConfig);
         ms.messages[from] ? {} += {error("Self import not allowed", from)};
-        ms.status[from] ? {} += {check_error()};
+        ms = addProperty(from, ms, check_error());
     }
     return ms;
 }
@@ -69,7 +69,7 @@ ModuleStatus reportCycles(rel[MODID, PathRole, MODID]paths, rel[MODID,MODID] ext
             mname = getRascalModuleName(mid, ms.pathConfig);
             causes = [ info("Part of extend cycle <getRascalModuleName(emid, ms.pathConfig)>", emid) | emid <- extendCycle ];
             ms.messages[mid] ? {} += {error("Extend cycle not allowed", mid, causes=causes)};
-            ms.status[mid] ? {} += {check_error()};
+            ms = addProperty(mid, ms, check_error());
         }
     }       
     pathsPlus = {<from, to> | <from, _, to> <- paths}+;
@@ -88,7 +88,7 @@ ModuleStatus reportCycles(rel[MODID, PathRole, MODID]paths, rel[MODID,MODID] ext
             causes = [ info("Part of mixed import/extend cycle <getRascalModuleName(eloc, ms.pathConfig)>", eloc) | eloc <- cycle ];
 
             ms.messages[mid] ? {} += { error("Mixed import/extend cycle not allowed", mid, causes=causes) };
-            ms.status[mid] ? {} += {check_error()};
+            ms = addProperty(mid, ms, check_error());
         }
     }
     return ms;
@@ -113,7 +113,7 @@ ModuleStatus completeModuleStatus(ModuleStatus ms){
              | < MODID c, MODID b> <- imports 
              };
 
-    ms.paths = paths;                                   
+    ms.paths = paths;                                
     return ms;
 }
 
@@ -134,14 +134,10 @@ ModuleStatus getImportAndExtendGraph(MODID moduleId, ModuleStatus ms){
     pcfg = ms.pathConfig;
     qualifiedModuleName = moduleId2moduleName(moduleId);
 
-    if(!ms.status[moduleId]?){
-        ms.status[moduleId] = {};
-    }
-
-    if(module_dependencies_extracted() in ms.status[moduleId]){
+    if(hasProperty(moduleId, ms, module_dependencies_extracted())){
         return ms;
     }
-    ms.status[moduleId] += module_dependencies_extracted();
+    ms = addProperty(moduleId, ms, module_dependencies_extracted());
 
     try {
       <found, tm, ms> = getTModelForModule(moduleId, ms);
@@ -156,9 +152,6 @@ ModuleStatus getImportAndExtendGraph(MODID moduleId, ModuleStatus ms){
         if(tm.store[key_bom]? && rel[str,datetime,PathRole] bom := tm.store[key_bom]){
            for(<str m, datetime timestampInBom, PathRole pathRole> <- bom){
                mid = moduleName2moduleId(m);
-               if(!ms.status[mid]?){
-                    ms.status[mid] = {};
-               }
                if(mid != moduleId){
                     localImportsAndExtends += <mid, pathRole>;
                }
@@ -168,9 +161,9 @@ ModuleStatus getImportAndExtendGraph(MODID moduleId, ModuleStatus ms){
                <mchanged, ms> = isModuleModified(mid, timestampInBom, pathRole, ms);
                if(dependencyChanged || mchanged){
                     allImportsAndExtendsValid = false;
-                    ms.status[mid] += rsc_changed();
-                    ms.status[mid] -= {tpl_uptodate(), checked()};
-                    ms.status[moduleId] -= tpl_saved();
+                    ms = addProperty(mid, ms, rsc_changed());
+                    ms = deleteProperty(mid, ms, tpl_uptodate(), checked());
+                    ms = deleteProperty(moduleId, ms, tpl_saved());
                     ms.messages[moduleId] = {};
                     if(ms.compilerConfig.verbose){
                         println("--- using <getLastModified(mid, ms)> (most recent) version of <m>,
@@ -187,11 +180,14 @@ ModuleStatus getImportAndExtendGraph(MODID moduleId, ModuleStatus ms){
             try {
                 try {
                     mloc = getRascalModuleLocation(moduleId, ms);
+                    if(endsWith(mloc.path, "tpl")){
+                        ms = addProperty(moduleId, ms, tpl_from_library());
+                    }
                 } catch Message err: {
                     ms.messages[moduleId] = { err };
                     tm = tmodel(modelName=moduleId2moduleName(moduleId), messages=[ err ]);
                     ms = addTModel(moduleId, tm, ms);
-                    ms.status[moduleId] += { rsc_not_found() };
+                    ms = addProperty(moduleId, ms, rsc_not_found());
                     return ms;
                 }
                 if(!isRascalLogicalLoc(mloc) && (mloc.extension != "rsc" || isModuleLocationInLibs(mloc, pcfg))) throw "No src or library module 1"; //There is only a tpl file available
@@ -225,25 +221,23 @@ ModuleStatus getImportAndExtendGraph(MODID moduleId, ModuleStatus ms){
             }
         }
         if(allImportsAndExtendsValid){
-            ms.status[moduleId] += {tpl_uptodate(), checked(), tpl_saved()}; //TODO: maybe check existence of generated java files
+            ms = addProperty(moduleId, ms, tpl_uptodate(), checked(), tpl_saved(), module_dependencies_extracted()); //TODO: maybe check existence of generated java files
             ms.moduleLocs += (moduleName2moduleId(mname) : tm.moduleLocs[mname] | mname <- tm.moduleLocs); // TODO: or not?
             ms.paths += tm.paths;
-            ms.status[moduleId] += module_dependencies_extracted();
             ms.messages[moduleId] ? {} += toSet(tm.messages);
-            for(<imp, _> <- localImportsAndExtends, isEmpty({module_dependencies_extracted()} & ms.status[imp])  ){
-                ms.status[imp] -= tpl_saved();
+            for(<imp, _> <- localImportsAndExtends, hasNotProperty(imp, ms, module_dependencies_extracted())  ){
+                ms = deleteProperty(imp, ms, tpl_saved());
                 ms = getImportAndExtendGraph(imp, ms);
             }
             return completeModuleStatus(ms);
          }
       }
     } catch rascalTplVersionError(str moduleName, loc tplLoc, str version, str txt):{
-        ms.status[moduleName2moduleId(moduleName)] += { tpl_version_error() };
+        ms = addProperty(moduleName2moduleId(moduleName), ms, tpl_version_error());
         // Need to recheck since TModel uses incompatible TPL version
     }
-
-    if(rsc_not_found() in ms.status[moduleId]){
-        if(tpl_version_error() in ms.status[moduleId]){
+    if(hasAnyProperty(moduleId, ms, rsc_not_found(), tpl_from_library())){
+        if(hasProperty(moduleId, ms, tpl_version_error())){
             iName = moduleId2moduleName(moduleId);
             for(<MODID m, _, moduleId> <- ms.paths){
                 mName = moduleId2moduleName(m);
@@ -257,11 +251,11 @@ ModuleStatus getImportAndExtendGraph(MODID moduleId, ModuleStatus ms){
     if(success){
         <ms, imports_and_extends> = getModulePaths(pt, ms);
 
-        for(<_, _, imp> <- imports_and_extends, rsc_not_found() notin ms.status[imp]){
+        for(<_, _, imp> <- imports_and_extends, hasNotProperty(imp, ms, rsc_not_found())){
             ms = getImportAndExtendGraph(imp, ms);
         }
     } else {
-         ms.status[moduleId] += rsc_not_found();
+        ms = addProperty(moduleId, ms, rsc_not_found());
     }
 
     return completeModuleStatus(ms);
@@ -360,15 +354,6 @@ tuple[ModuleStatus, rel[loc, PathRole, loc]] getModulePaths(Module m, ModuleStat
         iname = unescape("<imod.\module.name>");
         inameId = moduleName2moduleId(iname);
         imports_and_extends += <moduleId, imod is \default ? importPath() : extendPath(), inameId>;
-        ms.status[inameId] = ms.status[inameId] ? {};
-        // try {
-        //    // mloc = getRascalModuleLocation(iname, ms);
-        //     ms.paths += {<moduleId, imod is \default ? importPath() : extendPath(), inameId>};
-        //  } catch Message err: {
-        //     err.at = imod@\loc;
-        //     ms.messages[moduleId] ? {} += { err };
-        //     ms.status[inameId] += { rsc_not_found() };
-        //  }
     }
     ms.paths += imports_and_extends;
     return <ms, imports_and_extends>;
@@ -396,15 +381,14 @@ tuple[map[MODID,TModel], ModuleStatus] prepareForCompilation(set[MODID] componen
     pcfg = ms.pathConfig;
 
     dependencies_ok = true;
-    for(m <- component, rsc_not_found() notin ms.status[m], MStatus::ignored() notin ms.status[m]){
-        if(parse_error() in ms.status[m]){
+    for(m <- component, hasNotProperty(m, ms, rsc_not_found(), ModuleProperty::ignored())){
+        if(hasProperty(m, ms, parse_error())){
             return <(m : tmodel(modelName=moduleId2moduleName(m),messages=toList(ms.messages[m]))) ,ms>;
         }
-        for(imp <- m_imports[m] + m_extends[m], rsc_not_found() notin ms.status[imp], MStatus::ignored() notin ms.status[m]){
-            imp_status = ms.status[imp];
-            if(parse_error() in imp_status || checked() notin imp_status){
+        for(imp <- m_imports[m] + m_extends[m], hasNotProperty(imp, ms, rsc_not_found()), hasNotProperty(m, ms, ModuleProperty::ignored())){
+            if(hasProperty(imp, ms, parse_error()) || hasNotProperty(imp, ms, checked())){
                 dependencies_ok = false;
-                cause = (rsc_not_found() in imp_status) ? "module not found" : "due to syntax error";
+                cause = hasProperty(imp, ms, rsc_not_found()) ? "module not found" : "due to syntax error";
                 ms.messages[m] = (ms.messages[imp] ? {}) + error("<imp in m_imports[imp] ? "Imported" : "Extended"> module <imp> could not be checked (<cause>)", m);
             }
         }
@@ -414,7 +398,7 @@ tuple[map[MODID,TModel], ModuleStatus] prepareForCompilation(set[MODID] componen
     }
     transient_tms = (m : tm | m <- component);
     org_tm = tm;
-    for(MODID m <- component, rsc_not_found() notin ms.status[m], MStatus::ignored() notin ms.status[m]){
+    for(MODID m <- component, hasNotProperty(m, ms, rsc_not_found(), ModuleProperty::ignored())){
         tm = org_tm;
         mname = moduleId2moduleName(m);
         tm.modelName = mname;
@@ -433,7 +417,7 @@ tuple[map[MODID,TModel], ModuleStatus] prepareForCompilation(set[MODID] componen
 ModuleStatus doSaveModule(set[MODID] component, map[MODID,set[MODID]] m_imports, map[MODID,set[MODID]] m_extends, ModuleStatus ms, map[MODID, TModel] transient_tms, RascalCompilerConfig compilerConfig){
     pcfg = ms.pathConfig;
 
-    component = { m | m <- component, MStatus::ignored() notin ms.status[m] };
+    component = { m | m <- component, hasNotProperty(m, ms, ModuleProperty::ignored()) };
     if(isEmpty(component)) return ms;
 
     //println("doSaveModule: <component>, <m_imports>, <m_extends>, <moduleScopes>");
@@ -459,9 +443,9 @@ ModuleStatus doSaveModule(set[MODID] component, map[MODID,set[MODID]] m_imports,
 
         bom = makeBom(currentModule, ms);
 
-        extendedModuleScopes = {m | MODID m <- extends, checked() in ms.status[m]};
+        extendedModuleScopes = {m | MODID m <- extends, hasProperty(m, ms, checked())};
         extendedModuleScopes += {*tm.paths[ems,importPath()] | MODID ems <- extendedModuleScopes}; // add imports of extended modules
-        filteredModuleScopes = {m | MODID m <- (currentModule + imports), checked() in ms.status[m]} + extendedModuleScopes;
+        filteredModuleScopes = {m | MODID m <- (currentModule + imports), hasProperty(m, ms, checked())} + extendedModuleScopes;
 
         TModel m1 = tmodel();
         m1.version = getCurrentTplVersion();
@@ -531,7 +515,7 @@ ModuleStatus doSaveModule(set[MODID] component, map[MODID,set[MODID]] m_imports,
                     case loc l : if(!isEmpty(l.fragment)) insert l[fragment=""];
                  };
         m1.logical2physical = tm.logical2physical;
-        ms.status[currentModule] -= {tpl_saved()};
+        ms = deleteProperty(currentModule, ms, tpl_saved());
         ms = addTModel(currentModule, m1, ms);
     // println("TModel for <currentModule>:"); iprintln(m1);
     }
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/TestConfigs.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/check/TestConfigs.rsc
index 55fadfad48e..52c8618e7ba 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/TestConfigs.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/TestConfigs.rsc
@@ -50,6 +50,7 @@ public loc RASCAL       = |mvn://org.rascalmpl--rascal--0.41.0-RC15/|;
 public loc RASCAL42     = |mvn://org.rascalmpl--rascal--0.42.0-RC2/|;
 loc TYPEPAL             = |mvn://org.rascalmpl--typepal--0.14.8/|;
 loc OUTDATED_TYPEPAL    = |mvn://org.rascalmpl--typepal--0.14.1/|;
+loc TYPEPAL166          = |mvn://org.rascalmpl--typepal--0.16.6-RC1/|;
 
 loc DRAMBIGUITY         = |mvn://org.rascalmpl--drambiguity--0.1.2/|;
 loc FLYBYTES            = |mvn://org.rascalmpl--flybytes--0.1.5/|;
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/ChangeScenarioTests.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/ChangeScenarioTests.rsc
index cef2ace5073..28d9b0f1ca0 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/ChangeScenarioTests.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/ChangeScenarioTests.rsc
@@ -775,6 +775,47 @@ test bool onlyChangedModulesAreReChecked2(){
     return true;
 }
 
+loc TYPEPAL166 = |mvn://org.rascalmpl--typepal--0.16.6-RC1/|;
+test bool changeMultipleTimes() { // ht @toinehartman
+    loc projDir = |memory:///incremental-test/proj|;
+    loc checkerModule = projDir + "src" + "Checker.rsc";
+
+    PathConfig pcfg = pathConfig(
+        projectRoot = projDir,
+        srcs = [projDir + "src"],
+        bin = projDir + "target",
+        // There might be incompatibility here, since Rascal uses typepal--0.16.6-RC2 at the time of writing.
+        // However, I would still expect that errors caused by that appear on the first type-check.
+        libs = [TYPEPAL166, RASCAL42]
+    );
+    iprintln(pcfg);
+
+    // Clean
+    remove(projDir);
+    writeFile(checkerModule, "
+        module Checker
+        extend analysis::typepal::TypePal;
+        void collect(Collector c) { ; }
+    ");
+
+    // First check
+    println("Initial check");
+    if (!checkModuleOK(checkerModule, pathConfig = pcfg)) {
+        throw "First check failed; supposed to be OK.";
+    }
+    int N_TRIES = 10;
+    // Since this seems sporadically succeed, we run this a couple of times until it fails
+    for (i <- [1..N_TRIES + 1]) {
+        // Follow-up check
+        println("Follow-up check #<i>");
+        touch(checkerModule);
+        if (!checkModuleOK(checkerModule, pathConfig = pcfg)) {
+            return false;
+        }
+    }
+    return true;
+}
+
 // Benchmarks for incremental type checking
 
 void benchmark(str title, lrel[str, void()] cases){
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/StaticTestingUtils.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/StaticTestingUtils.rsc
index 7df51994e74..641121e9b30 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/StaticTestingUtils.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/StaticTestingUtils.rsc
@@ -107,11 +107,11 @@ void removeModule(str mname){
 
 void printModules(){
 	println("\<\<\<\<");
-	for(f <- find(|memory:///test-modules/|, "rsc")){
+	for(f <- find(|memory:///|, "rsc")){
 		println("<f> <lastModified(f)>:
 				'<readFile(f)>");
 	}
-	for(f <- find(|memory:///test-modules/|, "tpl")){
+	for(f <- find(|memory:///|, "tpl")){
 		println("<f>: <lastModified(f)>");
 	}
 	println("\>\>\>\>");
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/download-test-jars.sh b/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/download-test-jars.sh
index de70619a004..84f0a0d91b0 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/download-test-jars.sh
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/check/tests/download-test-jars.sh
@@ -11,6 +11,7 @@ download "org.rascalmpl" "rascal" "0.41.0-RC15"
 download "org.rascalmpl" "rascal" "0.42.0-RC2"
 download "org.rascalmpl" "typepal" "0.14.8" 
 download "org.rascalmpl" "typepal" "0.14.1" 
+download "org.rascalmpl" "typepal" "0.16.6-RC1" 
 download "org.rascalmpl" "drambiguity" "0.1.2" 
 download "org.rascalmpl" "flybytes" "0.1.5" 
 download "org.rascalmpl" "salix-core" "0.2.7" 
diff --git a/src/org/rascalmpl/compiler/lang/rascalcore/compile/Compile.rsc b/src/org/rascalmpl/compiler/lang/rascalcore/compile/Compile.rsc
index f70913380eb..8946aeb5af2 100644
--- a/src/org/rascalmpl/compiler/lang/rascalcore/compile/Compile.rsc
+++ b/src/org/rascalmpl/compiler/lang/rascalcore/compile/Compile.rsc
@@ -90,7 +90,7 @@ list[Message] compile1(MODID moduleId, lang::rascal::\syntax::Rascal::Module M,
     imports = { imp | <m1, importPath(), imp> <- ms.paths, m1 == moduleId };
     extends = { ext | <m1, extendPath(), ext > <- ms.paths, m1 == moduleId };
     tmodels = ();
-    for(m <- imports + extends, tpl_uptodate() in ms.status[m]){
+    for(m <- imports + extends, hasProperty(m, ms, tpl_uptodate())){
         if(m in transient_tms){
             tmodels[m] = transient_tms[m];
         } else {