Shut up some clang warnings

src/libexpr/eval-cache.hh

@@ -11,7 +11,7 @@ namespace nix::eval_cache {
 
 MakeError(CachedEvalError, EvalError);
 
-class AttrDb;
+struct AttrDb;
 class AttrCursor;
 
 class EvalCache : public std::enable_shared_from_this<EvalCache>

src/libfetchers/fetchers.hh

@@ -86,6 +86,9 @@ public:
 
 struct InputScheme
 {
+    virtual ~InputScheme()
+    { }
+
     virtual std::optional<Input> inputFromURL(const ParsedURL & url) = 0;
 
     virtual std::optional<Input> inputFromAttrs(const Attrs & attrs) = 0;

src/libfetchers/github.cc

@@ -25,7 +25,7 @@ struct GitArchiveInputScheme : InputScheme
 {
     virtual std::string type() = 0;
 
-    virtual std::optional<std::pair<std::string, std::string> > accessHeaderFromToken(const std::string & token) const = 0;
+    virtual std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const = 0;
 
     std::optional<Input> inputFromURL(const ParsedURL & url) override
     {
@@ -215,7 +215,7 @@ struct GitHubInputScheme : GitArchiveInputScheme
 {
     std::string type() override { return "github"; }
 
-    std::optional<std::pair<std::string, std::string> > accessHeaderFromToken(const std::string & token) const
+    std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const override
     {
         // Github supports PAT/OAuth2 tokens and HTTP Basic
         // Authentication.  The former simply specifies the token, the
@@ -270,7 +270,7 @@ struct GitLabInputScheme : GitArchiveInputScheme
 {
     std::string type() override { return "gitlab"; }
 
-    std::optional<std::pair<std::string, std::string> > accessHeaderFromToken(const std::string & token) const
+    std::optional<std::pair<std::string, std::string>> accessHeaderFromToken(const std::string & token) const override
     {
         // Gitlab supports 4 kinds of authorization, two of which are
         // relevant here: OAuth2 and PAT (Private Access Token).  The

src/libstore/dummy-store.cc

@@ -18,8 +18,7 @@ struct DummyStore : public Store, public virtual DummyStoreConfig
     DummyStore(const Params & params)
         : StoreConfig(params)
         , Store(params)
-    {
-    }
+    { }
 
     string getUri() override
     {

src/libstore/store-api.hh

@@ -194,6 +194,8 @@ struct StoreConfig : public Config
      */
     StoreConfig() { assert(false); }
 
+    virtual ~StoreConfig() { }
+
     virtual const std::string name() = 0;
 
     const PathSetting storeDir_{this, false, settings.nixStore,