diff --git a/src/plugins/beautifier/artisticstyle/artisticstyle.cpp b/src/plugins/beautifier/artisticstyle/artisticstyle.cpp
index 76914cf3440..bb9059652cb 100644
--- a/src/plugins/beautifier/artisticstyle/artisticstyle.cpp
+++ b/src/plugins/beautifier/artisticstyle/artisticstyle.cpp
@@ -41,8 +41,9 @@
 #include <coreplugin/editormanager/ieditor.h>
 #include <coreplugin/idocument.h>
 #include <cppeditor/cppeditorconstants.h>
-#include <projectexplorer/projecttree.h>
 #include <projectexplorer/project.h>
+#include <projectexplorer/projectnodes.h>
+#include <projectexplorer/projecttree.h>
 #include <texteditor/formattexteditor.h>
 #include <utils/fileutils.h>
 #include <utils/hostosinfo.h>
@@ -103,10 +104,9 @@ QString ArtisticStyle::configurationFile() const
     if (m_settings.useOtherFiles()) {
         if (const ProjectExplorer::Project *project
                 = ProjectExplorer::ProjectTree::currentProject()) {
-            const Utils::FilePathList files = project->files(ProjectExplorer::Project::AllFiles);
-            for (const Utils::FilePath &file : files) {
-                if (!file.endsWith(".astylerc"))
-                    continue;
+            const Utils::FilePathList astyleRcfiles = project->files(
+                [](const ProjectExplorer::Node *n) { return n->filePath().endsWith(".astylerc"); });
+            for (const Utils::FilePath &file : astyleRcfiles) {
                 const QFileInfo fi = file.toFileInfo();
                 if (fi.isReadable())
                     return file.toString();
diff --git a/src/plugins/beautifier/beautifierplugin.cpp b/src/plugins/beautifier/beautifierplugin.cpp
index 6e4cb079f20..798724d1856 100644
--- a/src/plugins/beautifier/beautifierplugin.cpp
+++ b/src/plugins/beautifier/beautifierplugin.cpp
@@ -161,7 +161,7 @@ void BeautifierPluginPrivate::autoFormatOnSave(Core::IDocument *document)
     // Check if file is contained in the current project (if wished)
     if (m_generalSettings->autoFormatOnlyCurrentProject()) {
         const ProjectExplorer::Project *pro = ProjectExplorer::ProjectTree::currentProject();
-        if (!pro || !pro->files(ProjectExplorer::Project::SourceFiles).contains(document->filePath())) {
+        if (!pro || !pro->isKnownFile(document->filePath())) {
             return;
         }
     }
diff --git a/src/plugins/beautifier/uncrustify/uncrustify.cpp b/src/plugins/beautifier/uncrustify/uncrustify.cpp
index b9db9037929..65ee86d9f70 100644
--- a/src/plugins/beautifier/uncrustify/uncrustify.cpp
+++ b/src/plugins/beautifier/uncrustify/uncrustify.cpp
@@ -41,8 +41,9 @@
 #include <coreplugin/editormanager/ieditor.h>
 #include <coreplugin/idocument.h>
 #include <cppeditor/cppeditorconstants.h>
-#include <projectexplorer/projecttree.h>
 #include <projectexplorer/project.h>
+#include <projectexplorer/projectnodes.h>
+#include <projectexplorer/projecttree.h>
 #include <texteditor/formattexteditor.h>
 #include <texteditor/texteditor.h>
 #include <utils/fileutils.h>
@@ -144,10 +145,9 @@ QString Uncrustify::configurationFile() const
     if (m_settings.useOtherFiles()) {
         if (const ProjectExplorer::Project *project
                 = ProjectExplorer::ProjectTree::currentProject()) {
-            const Utils::FilePathList files = project->files(ProjectExplorer::Project::AllFiles);
+            const Utils::FilePathList files = project->files(
+                [](const ProjectExplorer::Node *n) { return n->filePath().endsWith("cfg"); });
             for (const Utils::FilePath &file : files) {
-                if (!file.endsWith("cfg"))
-                    continue;
                 const QFileInfo fi = file.toFileInfo();
                 if (fi.isReadable() && fi.fileName() == "uncrustify.cfg")
                     return file.toString();
diff --git a/src/plugins/cmakeprojectmanager/cmakeproject.cpp b/src/plugins/cmakeprojectmanager/cmakeproject.cpp
index c836d09ef26..34d546335ef 100644
--- a/src/plugins/cmakeprojectmanager/cmakeproject.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeproject.cpp
@@ -634,9 +634,12 @@ QStringList CMakeProject::filesGeneratedFrom(const QString &sourceFile) const
 
 ProjectExplorer::DeploymentKnowledge CMakeProject::deploymentKnowledge() const
 {
-    return contains(files(AllFiles), [](const FilePath &f) {
-        return f.fileName() == "QtCreatorDeployment.txt";
-    }) ? DeploymentKnowledge::Approximative : DeploymentKnowledge::Bad;
+    return !files([](const ProjectExplorer::Node *n) {
+                return n->filePath().fileName() == "QtCreatorDeployment.txt";
+            })
+                   .isEmpty()
+               ? DeploymentKnowledge::Approximative
+               : DeploymentKnowledge::Bad;
 }
 
 MakeInstallCommand CMakeProject::makeInstallCommand(const Target *target,
diff --git a/src/plugins/cppeditor/resourcepreviewhoverhandler.cpp b/src/plugins/cppeditor/resourcepreviewhoverhandler.cpp
index 082c04493d4..1b70afa4b0c 100644
--- a/src/plugins/cppeditor/resourcepreviewhoverhandler.cpp
+++ b/src/plugins/cppeditor/resourcepreviewhoverhandler.cpp
@@ -26,14 +26,15 @@
 #include "resourcepreviewhoverhandler.h"
 
 #include <coreplugin/icore.h>
-#include <utils/tooltip/tooltip.h>
-#include <utils/fileutils.h>
-#include <utils/qtcassert.h>
-#include <utils/mimetypes/mimedatabase.h>
-#include <projectexplorer/projecttree.h>
 #include <projectexplorer/project.h>
+#include <projectexplorer/projectnodes.h>
+#include <projectexplorer/projecttree.h>
 #include <texteditor/texteditor.h>
 #include <utils/executeondestruction.h>
+#include <utils/fileutils.h>
+#include <utils/mimetypes/mimedatabase.h>
+#include <utils/qtcassert.h>
+#include <utils/tooltip/tooltip.h>
 
 #include <QPoint>
 #include <QTextBlock>
@@ -143,10 +144,9 @@ static QString findResourceInProject(const QString &resName)
         return QString();
 
     if (auto *project = ProjectExplorer::ProjectTree::currentProject()) {
-        const Utils::FilePathList files = project->files(ProjectExplorer::Project::AllFiles);
+        const Utils::FilePathList files = project->files(
+            [](const ProjectExplorer::Node *n) { return n->filePath().endsWith(".qrc"); });
         for (const Utils::FilePath &file : files) {
-            if (!file.endsWith(".qrc"))
-                continue;
             const QFileInfo fi = file.toFileInfo();
             if (!fi.isReadable())
                 continue;
diff --git a/src/plugins/qmakeprojectmanager/qmakeproject.cpp b/src/plugins/qmakeprojectmanager/qmakeproject.cpp
index 938a3a404a6..d437032c5aa 100644
--- a/src/plugins/qmakeprojectmanager/qmakeproject.cpp
+++ b/src/plugins/qmakeprojectmanager/qmakeproject.cpp
@@ -764,7 +764,11 @@ static void notifyChangedHelper(const FilePath &fileName, QmakeProFile *file)
 void QmakeProject::notifyChanged(const FilePath &name)
 {
     for (QmakeProject *project : s_projects) {
-        if (project->files(QmakeProject::SourceFiles).contains(name))
+        if (!project
+                 ->files([&name](const ProjectExplorer::Node *n) {
+                     return Project::SourceFiles(n) && n->filePath() == name;
+                 })
+                 .isEmpty())
             notifyChangedHelper(name, project->rootProFile());
     }
 }