5 files changed, 19 insertions, 14 deletions
diff --git a/src/db/plugins/LazyDatabase.hxx b/src/db/plugins/LazyDatabase.hxx
index ae1b961d0..38b3fdc2a 100644
--- a/src/db/plugins/LazyDatabase.hxx
+++ b/src/db/plugins/LazyDatabase.hxx
@@ -43,7 +43,7 @@ public:
 
 	virtual const LightSong *GetSong(const char *uri_utf8,
 					 Error &error) const override;
-	virtual void ReturnSong(const LightSong *song) const;
+	void ReturnSong(const LightSong *song) const override;
 
 	virtual bool Visit(const DatabaseSelection &selection,
 			   VisitDirectory visit_directory,
diff --git a/src/db/plugins/ProxyDatabasePlugin.cxx b/src/db/plugins/ProxyDatabasePlugin.cxx
index fba72210d..5fd224bb5 100644
--- a/src/db/plugins/ProxyDatabasePlugin.cxx
+++ b/src/db/plugins/ProxyDatabasePlugin.cxx
@@ -103,7 +103,7 @@ public:
 	virtual void Close() override;
 	virtual const LightSong *GetSong(const char *uri_utf8,
 				     Error &error) const override;
-	virtual void ReturnSong(const LightSong *song) const;
+	void ReturnSong(const LightSong *song) const override;
 
 	virtual bool Visit(const DatabaseSelection &selection,
 			   VisitDirectory visit_directory,
@@ -731,7 +731,7 @@ ProxyDatabase::Visit(const DatabaseSelection &selection,
 {
 	// TODO: eliminate the const_cast
 	if (!const_cast<ProxyDatabase *>(this)->EnsureConnected(error))
-		return nullptr;
+		return false;
 
 	if (!visit_directory && !visit_playlist && selection.recursive &&
 	    (ServerSupportsSearchBase(connection)
@@ -757,7 +757,7 @@ ProxyDatabase::VisitUniqueTags(const DatabaseSelection &selection,
 {
 	// TODO: eliminate the const_cast
 	if (!const_cast<ProxyDatabase *>(this)->EnsureConnected(error))
-		return nullptr;
+		return false;
 
 	enum mpd_tag_type tag_type2 = Convert(tag_type);
 	if (tag_type2 == MPD_TAG_COUNT) {
@@ -810,7 +810,7 @@ ProxyDatabase::GetStats(const DatabaseSelection &selection,
 
 	// TODO: eliminate the const_cast
 	if (!const_cast<ProxyDatabase *>(this)->EnsureConnected(error))
-		return nullptr;
+		return false;
 
 	struct mpd_stats *stats2 =
 		mpd_run_stats(connection);
diff --git a/src/db/plugins/simple/SimpleDatabasePlugin.cxx b/src/db/plugins/simple/SimpleDatabasePlugin.cxx
index bc9c42d2d..00eb078bc 100644
--- a/src/db/plugins/simple/SimpleDatabasePlugin.cxx
+++ b/src/db/plugins/simple/SimpleDatabasePlugin.cxx
@@ -435,9 +435,12 @@ SimpleDatabase::Save(Error &error)
 bool
 SimpleDatabase::Mount(const char *uri, Database *db, Error &error)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(uri != nullptr);
-	assert(*uri != 0);
 	assert(db != nullptr);
+#endif
+	assert(*uri != 0);
 
 	ScopeDatabaseLock protect;
 
@@ -445,13 +448,13 @@ SimpleDatabase::Mount(const char *uri, Database *db, Error &error)
 	if (r.uri == nullptr) {
 		error.Format(db_domain, DB_CONFLICT,
 			     "Already exists: %s", uri);
-		return nullptr;
+		return false;
 	}
 
 	if (strchr(r.uri, '/') != nullptr) {
 		error.Format(db_domain, DB_NOT_FOUND,
 			     "Parent not found: %s", uri);
-		return nullptr;
+		return false;
 	}
 
 	Directory *mnt = r.directory->CreateChild(r.uri);
@@ -478,7 +481,7 @@ SimpleDatabase::Mount(const char *local_uri, const char *storage_uri,
 	if (cache_path.IsNull()) {
 		error.Format(db_domain, DB_NOT_FOUND,
 			     "No 'cache_directory' configured");
-		return nullptr;
+		return false;
 	}
 
 	std::string name(storage_uri);
diff --git a/src/db/plugins/simple/SimpleDatabasePlugin.hxx b/src/db/plugins/simple/SimpleDatabasePlugin.hxx
index eb225b2c8..dec2a3a7c 100644
--- a/src/db/plugins/simple/SimpleDatabasePlugin.hxx
+++ b/src/db/plugins/simple/SimpleDatabasePlugin.hxx
@@ -110,9 +110,9 @@ public:
 	virtual bool Open(Error &error) override;
 	virtual void Close() override;
 
-	virtual const LightSong *GetSong(const char *uri_utf8,
-					 Error &error) const override;
-	virtual void ReturnSong(const LightSong *song) const;
+	const LightSong *GetSong(const char *uri_utf8,
+				 Error &error) const override;
+	void ReturnSong(const LightSong *song) const override;
 
 	virtual bool Visit(const DatabaseSelection &selection,
 			   VisitDirectory visit_directory,
diff --git a/src/db/plugins/upnp/UpnpDatabasePlugin.cxx b/src/db/plugins/upnp/UpnpDatabasePlugin.cxx
index 8d7f1bda8..aea97aa8e 100644
--- a/src/db/plugins/upnp/UpnpDatabasePlugin.cxx
+++ b/src/db/plugins/upnp/UpnpDatabasePlugin.cxx
@@ -85,7 +85,7 @@ public:
 	virtual void Close() override;
 	virtual const LightSong *GetSong(const char *uri_utf8,
 					 Error &error) const override;
-	virtual void ReturnSong(const LightSong *song) const;
+	void ReturnSong(const LightSong *song) const override;
 
 	virtual bool Visit(const DatabaseSelection &selection,
 			   VisitDirectory visit_directory,
@@ -101,7 +101,9 @@ public:
 	virtual bool GetStats(const DatabaseSelection &selection,
 			      DatabaseStats &stats,
 			      Error &error) const override;
-	virtual time_t GetUpdateStamp() const {return 0;}
+	time_t GetUpdateStamp() const override {
+		return 0;
+	}
 
 protected:
 	bool Configure(const config_param &param, Error &error);