diff --git a/doomsday/apps/libdoomsday/include/doomsday/resource/resources.h b/doomsday/apps/libdoomsday/include/doomsday/resource/resources.h
index 9342743d4d..0567d8429a 100644
--- a/doomsday/apps/libdoomsday/include/doomsday/resource/resources.h
+++ b/doomsday/apps/libdoomsday/include/doomsday/resource/resources.h
@@ -82,7 +82,7 @@ class LIBDOOMSDAY_PUBLIC Resources : public de::System
     /**
      * Lookup a ResourceClass by symbolic @a name.
      */
-    ResourceClass &resClass(de::String name);
+    ResourceClass &resClass(const de::String& name);
 
     /**
      * Lookup a ResourceClass by @a id.
@@ -138,7 +138,7 @@ namespace res
     {
         auto const *path = reinterpret_cast<de::Path *>(context);
         /// @todo Use PathTree::Node::compare()
-        return manifest.path().toString().beginsWith(*path, de::CaseInsensitive);
+        return manifest.path().toString().beginsWith(path->toString(), de::CaseInsensitive);
     }
 }
 
@@ -148,7 +148,7 @@ namespace res
  *
  * @param className  Resource class name.
  */
-LIBDOOMSDAY_PUBLIC ResourceClass &App_ResourceClass(de::String className);
+LIBDOOMSDAY_PUBLIC ResourceClass &App_ResourceClass(const de::String& className);
 
 /// @overload
 LIBDOOMSDAY_PUBLIC ResourceClass &App_ResourceClass(resourceclassid_t classId);
diff --git a/doomsday/apps/libdoomsday/include/doomsday/resource/texturescheme.h b/doomsday/apps/libdoomsday/include/doomsday/resource/texturescheme.h
index 0b079f9195..9cdb8768a2 100644
--- a/doomsday/apps/libdoomsday/include/doomsday/resource/texturescheme.h
+++ b/doomsday/apps/libdoomsday/include/doomsday/resource/texturescheme.h
@@ -61,7 +61,7 @@ class LIBDOOMSDAY_PUBLIC TextureScheme
      * @param symbolicName  Symbolic name of the new subspace scheme. Must
      *                      have at least @ref min_name_length characters.
      */
-    explicit TextureScheme(de::String symbolicName);
+    explicit TextureScheme(const de::String& symbolicName);
 
     ~TextureScheme();
 
diff --git a/doomsday/apps/libdoomsday/src/resource/resources.cpp b/doomsday/apps/libdoomsday/src/resource/resources.cpp
index 1d0286b949..a673c50a1d 100644
--- a/doomsday/apps/libdoomsday/src/resource/resources.cpp
+++ b/doomsday/apps/libdoomsday/src/resource/resources.cpp
@@ -43,15 +43,15 @@ static Resources *theResources = nullptr;
 
 static String resolveUriSymbol(String const &symbol)
 {
-    if (!symbol.compare("App.DataPath", Qt::CaseInsensitive))
+    if (!symbol.compare("App.DataPath", CaseInsensitive))
     {
         return "data";
     }
-    else if (!symbol.compare("App.DefsPath", Qt::CaseInsensitive))
+    else if (!symbol.compare("App.DefsPath", CaseInsensitive))
     {
         return "defs";
     }
-    else if (!symbol.compare("Game.IdentityKey", Qt::CaseInsensitive))
+    else if (!symbol.compare("Game.IdentityKey", CaseInsensitive))
     {
         if (DoomsdayApp::game().isNull())
         {
@@ -61,7 +61,7 @@ static String resolveUriSymbol(String const &symbol)
         }
         return DoomsdayApp::game().id();
     }
-    else if (!symbol.compare("GamePlugin.Name", Qt::CaseInsensitive))
+    else if (!symbol.compare("GamePlugin.Name", CaseInsensitive))
     {
         auto &gx = DoomsdayApp::plugins().gameExports();
         if (DoomsdayApp::game().isNull() || !gx.GetPointer)
@@ -84,7 +84,7 @@ DE_PIMPL(Resources)
 , DE_OBSERVES(PackageLoader, Load)
 , DE_OBSERVES(PackageLoader, Unload)
 {
-    typedef QList<ResourceClass *> ResourceClasses;
+    typedef List<ResourceClass *> ResourceClasses;
 
     ResourceClasses     resClasses;
     NullResourceClass   nullResourceClass;
@@ -133,7 +133,7 @@ DE_PIMPL(Resources)
 
     ~Impl()
     {
-        qDeleteAll(resClasses);
+        deleteAll(resClasses);
         textures.clear();
 
         theResources = nullptr;
@@ -234,11 +234,11 @@ Resources &Resources::get()
     return *theResources;
 }
 
-ResourceClass &Resources::resClass(String name)
+ResourceClass &Resources::resClass(const String& name)
 {
     if (!name.isEmpty())
     {
-        foreach (ResourceClass *resClass, d->resClasses)
+        for (ResourceClass *resClass : d->resClasses)
         {
             if (!resClass->name().compareWithoutCase(name))
                 return *resClass;
@@ -255,7 +255,7 @@ ResourceClass &Resources::resClass(resourceclassid_t id)
         return *d->resClasses.at(uint(id));
     }
     /// @throw UnknownResourceClass Attempted with an unknown id.
-    throw UnknownResourceClassError("ResourceResources::toClass", QString("Invalid id '%1'").arg(int(id)));
+    throw UnknownResourceClassError("ResourceResources::toClass", stringf("Invalid id '%i'", int(id)));
 }
 
 NativePath Resources::nativeSavePath() const
@@ -324,7 +324,7 @@ String Resources::tryFindMusicFile(Record const &definition)
     {
         // All external music files are specified relative to the base path.
         String fullPath = App_BasePath() / songUri.path();
-        if (F_Access(fullPath.toUtf8().constData()))
+        if (F_Access(fullPath))
         {
             return fullPath;
         }
@@ -349,7 +349,7 @@ String Resources::tryFindMusicFile(Record const &definition)
     return "";  // None found.
 }
 
-ResourceClass &App_ResourceClass(String className)
+ResourceClass &App_ResourceClass(const String& className)
 {
     return Resources::get().resClass(className);
 }
@@ -377,18 +377,17 @@ static dint printMapsIndex2(Path const &like, de::Uri::ComposeAsTextFlags compos
     //if (!printSchemeName && scheme)
     //    heading += " in scheme '" + scheme->name() + "'";
     if (!like.isEmpty())
-        heading += " like \"" _E(b) + like.toStringRef() + _E(.) "\"";
+        heading += " like \"" _E(b) + like.toString() + _E(.) "\"";
     LOG_RES_MSG(_E(D) "%s:" _E(.)) << heading;
 
     // Print the result index.
-    qSort(found.begin(), found.end(), comparePathTreeNodePathsAscending<res::MapManifest>);
-    dint const numFoundDigits = de::max(3/*idx*/, M_NumDigits(found.count()));
+    std::sort(found.begin(), found.end(), comparePathTreeNodePathsAscending<res::MapManifest>);
+//    dint const numFoundDigits = de::max(3/*idx*/, M_NumDigits(found.count()));
     dint idx = 0;
     for (res::MapManifest *mapManifest : found)
     {
-        String info = String("%1: " _E(1) "%2" _E(.))
-                        .arg(idx, numFoundDigits)
-                        .arg(mapManifest->description(composeUriFlags));
+        String info = String::format(
+            "%3i: " _E(1) "%s" _E(.), idx, mapManifest->description(composeUriFlags).c_str());
 
         LOG_RES_MSG("  " _E(>)) << info;
         idx++;
@@ -428,19 +427,19 @@ static int printMaterialIndex2(world::MaterialScheme *scheme, Path const &like,
     if (!printSchemeName && scheme)
         heading += " in scheme '" + scheme->name() + "'";
     if (!like.isEmpty())
-        heading += " like \"" _E(b) + like.toStringRef() + _E(.) "\"";
+        heading += " like \"" _E(b) + like.toString() + _E(.) "\"";
     LOG_RES_MSG(_E(D) "%s:" _E(.)) << heading;
 
     // Print the result index.
-    qSort(found.begin(), found.end(), comparePathTreeNodePathsAscending<world::MaterialManifest>);
-    int const numFoundDigits = de::max(3/*idx*/, M_NumDigits(found.count()));
+    std::sort(found.begin(), found.end(), comparePathTreeNodePathsAscending<world::MaterialManifest>);
+//    int const num/FoundDigits = de::max(3/*idx*/, M_NumDigits(found.count()));
     int idx = 0;
-    foreach (world::MaterialManifest *manifest, found)
+    for (world::MaterialManifest *manifest : found)
     {
-        String info = String("%1: %2%3" _E(.))
-                        .arg(idx, numFoundDigits)
-                        .arg(manifest->hasMaterial()? _E(1) : _E(2))
-                        .arg(manifest->description(composeUriFlags));
+        String info = String::format("%#i: %s%s" _E(.),
+                        idx,
+                        manifest->hasMaterial()? _E(1) : _E(2),
+                        manifest->description(composeUriFlags).c_str());
 
         LOG_RES_MSG("  " _E(>)) << info;
         idx++;
@@ -465,9 +464,9 @@ static int printTextureIndex2(res::TextureScheme *scheme, Path const &like,
     }
     else  // Consider resources in any scheme.
     {
-        foreach (res::TextureScheme *scheme, res::Textures::get().allTextureSchemes())
+        for (const auto &s : res::Textures::get().allTextureSchemes())
         {
-            scheme->index().findAll(found, res::pathBeginsWithComparator, const_cast<Path *>(&like));
+            s.second->index().findAll(found, res::pathBeginsWithComparator, const_cast<Path *>(&like));
         }
     }
     if (found.isEmpty()) return 0;
@@ -479,19 +478,19 @@ static int printTextureIndex2(res::TextureScheme *scheme, Path const &like,
     if (!printSchemeName && scheme)
         heading += " in scheme '" + scheme->name() + "'";
     if (!like.isEmpty())
-        heading += " like \"" _E(b) + like.toStringRef() + _E(.) "\"";
+        heading += " like \"" _E(b) + like.toString() + _E(.) "\"";
     LOG_RES_MSG(_E(D) "%s:" _E(.)) << heading;
 
     // Print the result index key.
-    qSort(found.begin(), found.end(), comparePathTreeNodePathsAscending<res::TextureManifest>);
-    int numFoundDigits = de::max(3/*idx*/, M_NumDigits(found.count()));
+    std::sort(found.begin(), found.end(), comparePathTreeNodePathsAscending<res::TextureManifest>);
+//    int numFoundDigits = de::max(3/*idx*/, M_NumDigits(found.count()));
     int idx = 0;
-    foreach (res::TextureManifest *manifest, found)
+    for (res::TextureManifest *manifest : found)
     {
-        String info = String("%1: %2%3")
-                        .arg(idx, numFoundDigits)
-                        .arg(manifest->hasTexture()? _E(0) : _E(2))
-                        .arg(manifest->description(composeUriFlags));
+        String info = String::format("%3i: %s%s",
+                        idx,
+                        manifest->hasTexture()? _E(0) : _E(2),
+                        manifest->description(composeUriFlags).c_str());
 
         LOG_RES_MSG("  " _E(>)) << info;
         idx++;
@@ -566,9 +565,9 @@ static void printTextureIndex(de::Uri const &search,
     else
     {
         // Collect and sort results in each scheme separately.
-        foreach (res::TextureScheme *scheme, textures.allTextureSchemes())
+        for (const auto &s : textures.allTextureSchemes())
         {
-            int numPrinted = printTextureIndex2(scheme, search.path(), flags | de::Uri::OmitScheme);
+            int numPrinted = printTextureIndex2(s.second, search.path(), flags | de::Uri::OmitScheme);
             if (numPrinted)
             {
                 LOG_RES_MSG(_E(R));
@@ -674,13 +673,13 @@ D_CMD(PrintTextureStats)
     DE_UNUSED(src, argc, argv);
 
     LOG_MSG(_E(b) "Texture Statistics:");
-    foreach (res::TextureScheme *scheme, res::Textures::get().allTextureSchemes())
+    for (const auto &s : res::Textures::get().allTextureSchemes())
     {
-        res::TextureScheme::Index const &index = scheme->index();
+        res::TextureScheme::Index const &index = s.second->index();
 
         uint const count = index.count();
         LOG_MSG("Scheme: %s (%u %s)")
-            << scheme->name() << count << (count == 1? "texture" : "textures");
+            << s.second->name() << count << (count == 1? "texture" : "textures");
         index.debugPrintHashDistribution();
         index.debugPrint();
     }
diff --git a/doomsday/apps/libdoomsday/src/resource/textures.cpp b/doomsday/apps/libdoomsday/src/resource/textures.cpp
index ef6d486722..97a979b20d 100644
--- a/doomsday/apps/libdoomsday/src/resource/textures.cpp
+++ b/doomsday/apps/libdoomsday/src/resource/textures.cpp
@@ -351,8 +351,7 @@ DE_PIMPL(Textures)
 
         // Process each definition file.
         int origIndexBase = 0;
-        //DE_FOR_EACH_CONST(QList<File1 *>, i, defFiles)
-        foreach (auto *file, defFiles)
+        for (auto *file : defFiles)
         {
             //File1 &file = **i;
 
@@ -383,8 +382,8 @@ DE_PIMPL(Textures)
 
             // Print a summary.
             LOG_RES_MSG("Loaded %s texture definitions from \"%s:%s\"")
-                << (newDefs.count() == archiveCount? String("all %1").arg(newDefs.count())
-                                                   : String("%1 of %1").arg(newDefs.count()).arg(archiveCount))
+                << (newDefs.count() == archiveCount? String::format("all %i", newDefs.count())
+                                                   : String::format("%i of %i", newDefs.count(), archiveCount))
                 << NativePath(file->container().composeUri().asText()).pretty()
                 << NativePath(file->composeUri().asText()).pretty();
         }
@@ -395,9 +394,9 @@ DE_PIMPL(Textures)
 
             // Map the definitions for O(log n) lookup performance,
             CompositeTextureMap mappedCustomDefs;
-            foreach (Composite *custom, customDefs)
+            for (Composite *custom : customDefs)
             {
-                mappedCustomDefs.insert(custom->percentEncodedNameRef(), custom);
+                mappedCustomDefs.insert(std::make_pair(custom->percentEncodedNameRef(), custom));
             }
 
             // Perform reclassification of replaced texture definitions.
@@ -406,12 +405,12 @@ DE_PIMPL(Textures)
                 Composite *orig = defs[i];
 
                 // Does a potential replacement exist for this original definition?
-                CompositeTextureMap::const_iterator found = mappedCustomDefs.constFind(orig->percentEncodedNameRef());
-                if (found == mappedCustomDefs.constEnd())
+                CompositeTextureMap::const_iterator found = mappedCustomDefs.find(orig->percentEncodedNameRef());
+                if (found == mappedCustomDefs.end())
                     continue;
 
                 // Definition 'custom' is destined to replace 'orig'.
-                Composite *custom = found.value();
+                Composite *custom = found->second;
                 bool haveReplacement = false;
 
                 if (custom->isFlagged(Composite::Custom))
@@ -460,9 +459,9 @@ DE_PIMPL(Textures)
         while (!allDefs.isEmpty())
         {
             Composite &def = *allDefs.takeFirst();
-            de::Uri uri(QStringLiteral("Textures"), Path(def.percentEncodedName()));
+            de::Uri uri(DE_STR("Textures"), Path(def.percentEncodedName()));
 
-            Texture::Flags flags;
+            Flags flags;
             if (def.isFlagged(Composite::Custom)) flags |= Texture::Custom;
 
             /*
@@ -559,10 +558,10 @@ DE_PIMPL(Textures)
                     !percentEncodedName.compareWithoutCase("F_END")    ||
                     !percentEncodedName.compareWithoutCase("FF_END")) continue;
 
-                de::Uri uri(QStringLiteral("Flats"), Path(percentEncodedName));
+                de::Uri uri(DE_STR("Flats"), Path(percentEncodedName));
                 if (self().textureManifestPtr(uri)) continue;
 
-                Texture::Flags flags;
+                Flags flags;
                 if (file.container().hasCustom()) flags |= Texture::Custom;
 
                 /*
@@ -607,16 +606,16 @@ DE_PIMPL(Textures)
             File1 &file = index[i];
             String fileName = file.name().fileNameWithoutExtension();
 
-            if (fileName.beginsWith('S', String::CaseInsensitive) && fileName.length() >= 5)
+            if (fileName.beginsWith('S', CaseInsensitive) && fileName.length() >= 5)
             {
-                if (fileName.endsWith("_START", String::CaseInsensitive))
+                if (fileName.endsWith("_START", CaseInsensitive))
                 {
                     // We've arrived at *a* sprite block.
                     Stack_Push(stack, NULL);
                     continue;
                 }
 
-                if (Stack_Height(stack) > 0 && fileName.endsWith("_END", String::CaseInsensitive))
+                if (Stack_Height(stack) > 0 && fileName.endsWith("_END", CaseInsensitive))
                 {
                     // The sprite block ends.
                     Stack_Pop(stack);
@@ -626,7 +625,7 @@ DE_PIMPL(Textures)
 
             if (!Stack_Height(stack)) continue;
 
-            String decodedFileName = QString(QByteArray::fromPercentEncoding(fileName.toUtf8()));
+            String decodedFileName = String::fromPercentEncoding(fileName);
             if (!Sprites::isValidSpriteName(decodedFileName))
             {
                 LOG_RES_NOTE("Ignoring invalid sprite name '%s'") << decodedFileName;
@@ -635,7 +634,7 @@ DE_PIMPL(Textures)
 
             de::Uri const uri("Sprites", Path(fileName));
 
-            Texture::Flags flags = 0;
+            Flags flags = 0;
             // If this is from an add-on flag it as "custom".
             if (file.container().hasCustom())
             {
@@ -755,10 +754,10 @@ TextureScheme *Textures::textureSchemePtr(String const &name) const
 {
     if (!name.isEmpty())
     {
-        auto found = d->textureSchemes.constFind(name);
-        if (found != d->textureSchemes.constEnd())
+        auto found = d->textureSchemes.find(name);
+        if (found != d->textureSchemes.end())
         {
-            return *found;
+            return found->second;
         }
     }
     return nullptr;
@@ -815,12 +814,11 @@ TextureManifest *Textures::textureManifestPtr(de::Uri const &uri) const
     // Is this a URN? (of the form "urn:schemename:uniqueid")
     if (!uri.scheme().compareWithoutCase("urn"))
     {
-        String const &pathStr = uri.path().toStringRef();
-        dint uIdPos = pathStr.indexOf(':');
-        if (uIdPos > 0)
+        const String pathStr = uri.path().toString();
+        if (auto uIdPos = pathStr.indexOf(":"))
         {
             String schemeName = pathStr.left(uIdPos);
-            dint uniqueId     = pathStr.mid(uIdPos + 1 /*skip delimiter*/).toInt();
+            dint uniqueId     = pathStr.substr(uIdPos + 1 /*skip delimiter*/).toInt();
 
             if (auto *ts = textureSchemePtr(schemeName))
             {
@@ -861,7 +859,7 @@ Textures::AllTextures const &Textures::allTextures() const
 
 TextureManifest &Textures::declareSystemTexture(Path const &texturePath, de::Uri const &resourceUri)
 {
-    auto &scheme = textureScheme(QStringLiteral("System"));
+    auto &scheme = textureScheme(DE_STR("System"));
     dint const uniqueId = scheme.count() + 1;
     return scheme.declare(texturePath,
                           Texture::Custom,
@@ -875,7 +873,7 @@ Texture *Textures::tryFindTextureByResourceUri(String const &schemeName, de::Uri
 {
     if (!resourceUri.isEmpty())
     {
-        if (resourceUri.path().toStringRef() == QStringLiteral("-"))
+        if (resourceUri.path() == DE_STR("-"))
         {
             return nullptr;
         }
@@ -914,7 +912,7 @@ Texture *Textures::defineTexture(String const &schemeName,
         return nullptr;
     }
 
-    de::Uri uri(scheme.name(), Path(String("%1").arg(uniqueId, 8, 10, QChar('0'))));
+    de::Uri uri(scheme.name(), Path(String::format("%08i", uniqueId)));
     try
     {
         TextureManifest &manifest = declareTexture(uri, Texture::Custom, dimensions,
@@ -961,7 +959,7 @@ patchid_t Textures::declarePatch(String const &encodedName)
     if (encodedName.isEmpty())
         return 0;
 
-    de::Uri uri(QStringLiteral("Patches"), Path(encodedName));
+    de::Uri uri(DE_STR("Patches"), Path(encodedName));
 
     // Already defined as a patch?
     if (auto *mft = textureManifestPtr(uri))
@@ -982,7 +980,7 @@ patchid_t Textures::declarePatch(String const &encodedName)
     lumpnum_t const lumpNum = fs1.nameIndex().findLast(lumpPath);
     File1 &file = fs1.lump(lumpNum);
 
-    Texture::Flags flags;
+    Flags flags;
     if (file.container().hasCustom()) flags |= Texture::Custom;
 
     Vec2ui dimensions;
@@ -1010,7 +1008,7 @@ patchid_t Textures::declarePatch(String const &encodedName)
     }
     file.unlock();
 
-    dint uniqueId       = textureScheme(QStringLiteral("Patches")).count() + 1;  // 1-based index.
+    dint uniqueId       = textureScheme(DE_STR("Patches")).count() + 1;  // 1-based index.
     de::Uri resourceUri = LumpIndex::composeResourceUrn(lumpNum);
 
     try
diff --git a/doomsday/apps/libdoomsday/src/resource/texturescheme.cpp b/doomsday/apps/libdoomsday/src/resource/texturescheme.cpp
index 0040535393..0f8e4ce37e 100644
--- a/doomsday/apps/libdoomsday/src/resource/texturescheme.cpp
+++ b/doomsday/apps/libdoomsday/src/resource/texturescheme.cpp
@@ -57,7 +57,7 @@ DE_PIMPL(TextureScheme)
 
     bool inline uniqueIdInLutRange(int uniqueId) const
     {
-        return (uniqueId - uniqueIdBase >= 0 && (uniqueId - uniqueIdBase) < uniqueIdLut.size());
+        return (uniqueId - uniqueIdBase >= 0 && (uniqueId - uniqueIdBase) < uniqueIdLut.sizei());
     }
 
     void findUniqueIdRange(int *minId, int *maxId)
@@ -128,7 +128,7 @@ DE_PIMPL(TextureScheme)
         // Fill the LUT with initial values.
         uniqueIdLut.reserve(lutSize);
         int i = 0;
-        for (; i < uniqueIdLut.size(); ++i)
+        for (; i < uniqueIdLut.sizei(); ++i)
         {
             uniqueIdLut[i] = 0;
         }
@@ -164,7 +164,8 @@ DE_PIMPL(TextureScheme)
     }
 };
 
-TextureScheme::TextureScheme(String symbolicName) : d(new Impl(this, symbolicName))
+TextureScheme::TextureScheme(const String& symbolicName)
+    : d(new Impl(this, symbolicName))
 {}
 
 TextureScheme::~TextureScheme()
diff --git a/doomsday/apps/libdoomsday/src/world/entitydef.cpp b/doomsday/apps/libdoomsday/src/world/entitydef.cpp
index ea9961fd9d..215d17e6e0 100644
--- a/doomsday/apps/libdoomsday/src/world/entitydef.cpp
+++ b/doomsday/apps/libdoomsday/src/world/entitydef.cpp
@@ -164,33 +164,25 @@ void MapEntityDef_AddProperty(MapEntityDef* def, int propertyId, const char* pro
         break;
 
     default:
-        throw Error("MapEntityDef_AddProperty", QString("Unknown/not supported value type %1").arg(type));
+        throw Error("MapEntityDef_AddProperty", stringf("Unknown/not supported value type %i", type));
     }
 
     // Ensure both the identifer and the name for the new property are unique.
     if (MapEntityDef_Property(def, propertyId) >= 0)
-        throw Error("MapEntityDef_AddProperty", QString("propertyId %1 not unique for %2")
-                                                    .arg(propertyId).arg(Str_Text(P_NameForMapEntityDef(def))));
+        throw Error("MapEntityDef_AddProperty", stringf("propertyId %i not unique for %s",
+                                                    propertyId, Str_Text(P_NameForMapEntityDef(def))));
     if (MapEntityDef_PropertyByName(def, propertyName) >= 0)
-        throw Error("MapEntityDef_AddProperty", QString("propertyName \"%1\" not unique for %2")
-                                                    .arg(propertyName).arg(Str_Text(P_NameForMapEntityDef(def))));
+        throw Error("MapEntityDef_AddProperty", stringf("propertyName \"%s\" not unique for %s",
+                                                    propertyName, Str_Text(P_NameForMapEntityDef(def))));
 
     // Looks good! Add it to the list of properties.
     def->props = (MapEntityPropertyDef*) M_Realloc(def->props, ++def->numProps * sizeof(*def->props));
-    if (!def->props)
-        throw Error("MapEntityDef_AddProperty",
-                        QString("Failed on (re)allocation of %1 bytes for new MapEntityPropertyDef array")
-                            .arg((unsigned long) sizeof(*def->props)));
 
     MapEntityPropertyDef* prop = &def->props[def->numProps - 1];
     prop->id = propertyId;
 
     int len = (int)strlen(propertyName);
     prop->name = (char *) M_Malloc(sizeof(*prop->name) * (len + 1));
-    if (!prop->name)
-        throw Error("MapEntityDef_AddProperty",
-                        QString("Failed on allocation of %1 bytes for property name")
-                            .arg((unsigned long) (sizeof(*prop->name) * (len + 1))));
 
     strncpy(prop->name, propertyName, len);
     prop->name[len] = '\0';
@@ -251,13 +243,15 @@ DE_EXTERN_C dd_bool P_RegisterMapObj(int identifier, char const *name)
     return findMapEntityDef(identifier, name, true /*do create*/) != 0;
 }
 
-DE_EXTERN_C dd_bool P_RegisterMapObjProperty(int entityId, int propertyId,
-                                               char const *propertyName, valuetype_t type)
+DE_EXTERN_C dd_bool P_RegisterMapObjProperty(int         entityId,
+                                             int         propertyId,
+                                             char const *propertyName,
+                                             valuetype_t type)
 {
     try
     {
         MapEntityDef *def = findMapEntityDef(entityId, 0, false /*do not create*/);
-        if (!def) throw Error("P_RegisterMapObjProperty", QString("Unknown entityId %1").arg(entityId));
+        if (!def) throw Error("P_RegisterMapObjProperty", stringf("Unknown entityId %i", entityId));
 
         MapEntityDef_AddProperty(def, propertyId, propertyName, type);
         return true; // Success!
@@ -284,14 +278,14 @@ static MapEntityPropertyDef *entityPropertyDef(int entityId, int propertyId)
 {
     // Is this a known entity?
     MapEntityDef *entity = P_MapEntityDef(entityId);
-    if (!entity) throw Error("entityPropertyDef", QString("Unknown entity definition id %1").arg(entityId));
+    if (!entity) throw Error("entityPropertyDef", stringf("Unknown entity definition id %i", entityId));
 
     // Is this a known property?
     MapEntityPropertyDef *property;
     if (MapEntityDef_Property(entity, propertyId, &property) < 0)
-        throw Error("entityPropertyDef", QString("Entity definition %1 has no property with id %2")
-                                                 .arg(Str_Text(P_NameForMapEntityDef(entity)))
-                                                 .arg(propertyId));
+        throw Error("entityPropertyDef", stringf("Entity definition %s has no property with id %i",
+                                                 Str_Text(P_NameForMapEntityDef(entity)),
+                                                 propertyId));
 
     return property; // Found it.
 }
@@ -308,7 +302,7 @@ static void setValue(void *dst, valuetype_t dstType, PropertyValue const &pvalue
     case DDVT_SHORT:  *(  (short *) dst) = pvalue.asInt16();  break;
     case DDVT_ANGLE:  *((angle_t *) dst) = pvalue.asAngle();  break;
     default:
-        throw Error("setValue", QString("Unknown value type %d").arg(dstType));
+        throw Error("setValue", stringf("Unknown value type %d", dstType));
     }
 }
 
diff --git a/doomsday/apps/libdoomsday/src/world/thinkerdata.cpp b/doomsday/apps/libdoomsday/src/world/thinkerdata.cpp
index 2c07643377..7ca8dff1bf 100644
--- a/doomsday/apps/libdoomsday/src/world/thinkerdata.cpp
+++ b/doomsday/apps/libdoomsday/src/world/thinkerdata.cpp
@@ -47,7 +47,7 @@ DE_PIMPL(ThinkerData)
 
     ~Impl()
     {
-        thinkerLookup.remove(id, &self());
+        multiRemove(thinkerLookup, id, &self());
 
         DE_FOR_PUBLIC_AUDIENCE2(Deletion, i)
         {
@@ -84,7 +84,7 @@ Id const &ThinkerData::id() const
 
 void ThinkerData::setId(Id const &id)
 {
-    thinkerLookup.remove(d->id, this);
+    multiRemove(thinkerLookup, d->id, this);
     thinkerLookup.insert(std::make_pair(id, this));
 
     d->id = id;
@@ -139,7 +139,7 @@ void ThinkerData::operator >> (Writer &to) const
 
 void ThinkerData::operator << (Reader &from)
 {
-    thinkerLookup.remove(d->id, this);
+    multiRemove(thinkerLookup, d->id, this);
 
     world::InternalSerialId sid;
     from >> sid;