tree-wide: fix a pile of lints

This:
- Converts a bunch of C style casts into C++ casts.
- Removes some very silly pointer subtraction code (which is no more or
  less busted on i686 than it began)
- Fixes some "technically UB" that never had to be UB in the first
  place.
- Makes finally follow the noexcept status of the inner function. Maybe
  in the future we should ban the function from not being noexcept, but
  that is not today.
- Makes various locally-used exceptions inherit from std::exception.

Change-Id: I22e66972602604989b5e494fd940b93e0e6e9297

27 files changed, 74 insertions, 69 deletions

diff --git a/src/libcmd/repl-interacter.cc b/src/libcmd/repl-interacter.cc
index 0cf4e34b8..6979e3db4 100644
--- a/src/libcmd/repl-interacter.cc
+++ b/src/libcmd/repl-interacter.cc
@@ -96,7 +96,7 @@ static int listPossibleCallback(char * s, char *** avp)
         return p;
     };
 
-    vp = check((char **) malloc(possible.size() * sizeof(char *)));
+    vp = check(static_cast<char **>(malloc(possible.size() * sizeof(char *))));
 
     for (auto & p : possible)
         vp[ac++] = check(strdup(p.c_str()));
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 741a24e3c..4885db68d 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -21,7 +21,6 @@
 #include "flake/flakeref.hh"
 
 #include <algorithm>
-#include <chrono>
 #include <iostream>
 #include <sstream>
 #include <cstring>
@@ -146,7 +145,7 @@ bool Value::isTrivial() const
         && internalType != tPrimOpApp
         && (internalType != tThunk
             || (dynamic_cast<ExprAttrs *>(thunk.expr)
-                && ((ExprAttrs *) thunk.expr)->dynamicAttrs.empty())
+                && (static_cast<ExprAttrs *>(thunk.expr))->dynamicAttrs.empty())
             || dynamic_cast<ExprLambda *>(thunk.expr)
             || dynamic_cast<ExprList *>(thunk.expr));
 }
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 228e4e1ba..dab96d6d4 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -346,7 +346,7 @@ void prim_importNative(EvalState & state, const PosIdx pos, Value * * args, Valu
         state.error<EvalError>("could not open '%1%': %2%", path, dlerror()).debugThrow();
 
     dlerror();
-    ValueInitializer func = (ValueInitializer) dlsym(handle, sym.c_str());
+    ValueInitializer func = reinterpret_cast<ValueInitializer>(dlsym(handle, sym.c_str()));
     if(!func) {
         char *message = dlerror();
         if (message)
@@ -2439,6 +2439,8 @@ static void prim_attrValues(EvalState & state, const PosIdx pos, Value * * args,
 
     state.mkList(v, args[0]->attrs->size());
 
+    // FIXME: this is incredibly evil, *why*
+    // NOLINTBEGIN(cppcoreguidelines-pro-type-cstyle-cast)
     unsigned int n = 0;
     for (auto & i : *args[0]->attrs)
         v.listElems()[n++] = (Value *) &i;
@@ -2452,6 +2454,7 @@ static void prim_attrValues(EvalState & state, const PosIdx pos, Value * * args,
 
     for (unsigned int i = 0; i < n; ++i)
         v.listElems()[i] = ((Attr *) v.listElems()[i])->value;
+    // NOLINTEND(cppcoreguidelines-pro-type-cstyle-cast)
 }
 
 static RegisterPrimOp primop_attrValues({
diff --git a/src/libmain/stack.cc b/src/libmain/stack.cc
index 10f71c1dc..493829b55 100644
--- a/src/libmain/stack.cc
+++ b/src/libmain/stack.cc
@@ -2,8 +2,6 @@
 #include "shared.hh"
 
 #include <cstring>
-#include <cstddef>
-#include <cstdlib>
 
 #include <unistd.h>
 #include <signal.h>
@@ -17,17 +15,17 @@ static void sigsegvHandler(int signo, siginfo_t * info, void * ctx)
        the stack pointer.  Unfortunately, getting the stack pointer is
        not portable. */
     bool haveSP = true;
-    char * sp = 0;
+    int64_t sp = 0;
 #if defined(__x86_64__) && defined(REG_RSP)
-    sp = (char *) ((ucontext_t *) ctx)->uc_mcontext.gregs[REG_RSP];
+    sp = static_cast<ucontext_t *>(ctx)->uc_mcontext.gregs[REG_RSP];
 #elif defined(REG_ESP)
-    sp = (char *) ((ucontext_t *) ctx)->uc_mcontext.gregs[REG_ESP];
+    sp = static_cast<ucontext_t *>(ctx)->uc_mcontext.gregs[REG_ESP];
 #else
     haveSP = false;
 #endif
 
     if (haveSP) {
-        ptrdiff_t diff = (char *) info->si_addr - sp;
+        int64_t diff = int64_t(info->si_addr) - sp;
         if (diff < 0) diff = -diff;
         if (diff < 4096) {
             nix::stackOverflowHandler(info, ctx);
diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index 9b1e22bad..fc0569a66 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -3,17 +3,15 @@
 #include "compression.hh"
 #include "derivations.hh"
 #include "fs-accessor.hh"
-#include "globals.hh"
 #include "nar-info.hh"
 #include "sync.hh"
 #include "remote-fs-accessor.hh"
-#include "nar-info-disk-cache.hh"
+#include "nar-info-disk-cache.hh" // IWYU pragma: keep
 #include "nar-accessor.hh"
 #include "thread-pool.hh"
 #include "signals.hh"
 
 #include <chrono>
-#include <future>
 #include <regex>
 #include <fstream>
 #include <sstream>
@@ -480,7 +478,8 @@ void BinaryCacheStore::addSignatures(const StorePath & storePath, const StringSe
        when addSignatures() is called sequentially on a path, because
        S3 might return an outdated cached version. */
 
-    auto narInfo = make_ref<NarInfo>((NarInfo &) *queryPathInfo(storePath));
+    // downcast: BinaryCacheStore always returns NarInfo from queryPathInfoUncached, making it sound
+    auto narInfo = make_ref<NarInfo>(dynamic_cast<NarInfo const &>(*queryPathInfo(storePath)));
 
     narInfo->sigs.insert(sigs.begin(), sigs.end());
 
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 87a2ef4bc..c435a3c00 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -1226,7 +1226,7 @@ void LocalDerivationGoal::startDaemon()
             socklen_t remoteAddrLen = sizeof(remoteAddr);
 
             AutoCloseFD remote{accept(daemonSocket.get(),
-                (struct sockaddr *) &remoteAddr, &remoteAddrLen)};
+                reinterpret_cast<struct sockaddr *>(&remoteAddr), &remoteAddrLen)};
             if (!remote) {
                 if (errno == EINTR || errno == EAGAIN) continue;
                 if (errno == EINVAL || errno == ECONNABORTED) break;
diff --git a/src/libstore/build/worker.cc b/src/libstore/build/worker.cc
index 04f0575b1..135cfecf5 100644
--- a/src/libstore/build/worker.cc
+++ b/src/libstore/build/worker.cc
@@ -4,7 +4,7 @@
 #include "drv-output-substitution-goal.hh"
 #include "local-derivation-goal.hh"
 #include "signals.hh"
-#include "hook-instance.hh"
+#include "hook-instance.hh" // IWYU pragma: keep
 
 #include <poll.h>
 
@@ -529,7 +529,7 @@ void Worker::waitForInput()
                 } else {
                     printMsg(lvlVomit, "%1%: read %2% bytes",
                         goal->getName(), rd);
-                    std::string_view data((char *) buffer.data(), rd);
+                    std::string_view data(reinterpret_cast<char *>(buffer.data()), rd);
                     j->lastOutput = after;
                     handleWorkResult(goal, goal->handleChildOutput(k, data));
                 }
diff --git a/src/libstore/crypto.cc b/src/libstore/crypto.cc
index 2e0fd8ca5..e8ab15537 100644
--- a/src/libstore/crypto.cc
+++ b/src/libstore/crypto.cc
@@ -44,16 +44,16 @@ std::string SecretKey::signDetached(std::string_view data) const
 {
     unsigned char sig[crypto_sign_BYTES];
     unsigned long long sigLen;
-    crypto_sign_detached(sig, &sigLen, (unsigned char *) data.data(), data.size(),
-        (unsigned char *) key.data());
-    return name + ":" + base64Encode(std::string((char *) sig, sigLen));
+    crypto_sign_detached(sig, &sigLen, reinterpret_cast<const unsigned char *>(data.data()), data.size(),
+        reinterpret_cast<const unsigned char *>(key.data()));
+    return name + ":" + base64Encode(std::string(reinterpret_cast<char *>(sig), sigLen));
 }
 
 PublicKey SecretKey::toPublicKey() const
 {
     unsigned char pk[crypto_sign_PUBLICKEYBYTES];
-    crypto_sign_ed25519_sk_to_pk(pk, (unsigned char *) key.data());
-    return PublicKey(name, std::string((char *) pk, crypto_sign_PUBLICKEYBYTES));
+    crypto_sign_ed25519_sk_to_pk(pk, reinterpret_cast<const unsigned char *>(key.data()));
+    return PublicKey(name, std::string(reinterpret_cast<char *>(pk), crypto_sign_PUBLICKEYBYTES));
 }
 
 SecretKey SecretKey::generate(std::string_view name)
@@ -63,7 +63,7 @@ SecretKey SecretKey::generate(std::string_view name)
     if (crypto_sign_keypair(pk, sk) != 0)
         throw Error("key generation failed");
 
-    return SecretKey(name, std::string((char *) sk, crypto_sign_SECRETKEYBYTES));
+    return SecretKey(name, std::string(reinterpret_cast<char *>(sk), crypto_sign_SECRETKEYBYTES));
 }
 
 PublicKey::PublicKey(std::string_view s)
@@ -85,9 +85,9 @@ bool verifyDetached(const std::string & data, const std::string & sig,
     if (sig2.size() != crypto_sign_BYTES)
         throw Error("signature is not valid");
 
-    return crypto_sign_verify_detached((unsigned char *) sig2.data(),
-        (unsigned char *) data.data(), data.size(),
-        (unsigned char *) key->second.key.data()) == 0;
+    return crypto_sign_verify_detached(reinterpret_cast<unsigned char *>(sig2.data()),
+        reinterpret_cast<const unsigned char *>(data.data()), data.size(),
+        reinterpret_cast<const unsigned char *>(key->second.key.data())) == 0;
 }
 
 PublicKeys getDefaultPublicKeys()
diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index aada43253..5ac9cd2ef 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -453,7 +453,11 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
                 hashAlgo = parseHashType(hashAlgoRaw);
             }
 
-            GeneratorSource dumpSource{[&]() -> WireFormatGenerator {
+            // Note to future maintainers: do *not* inline this into the
+            // generator statement as the lambda itself needs to live to the
+            // end of the generator's lifetime and is otherwise a UAF.
+            // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines): does not outlive the outer function
+            auto g = [&]() -> WireFormatGenerator {
                 if (method == FileIngestionMethod::Recursive) {
                     /* We parse the NAR dump through into `saved` unmodified,
                        so why all this extra work? We still parse the NAR so
@@ -489,7 +493,8 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
                     }
                     co_yield std::move(file->contents);
                 }
-            }()};
+            };
+            GeneratorSource dumpSource{g()};
             logger->startWork();
             auto path = store->addToStoreFromDump(dumpSource, baseName, method, hashAlgo);
             logger->stopWork();
diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc
index 9cb805444..11c8a755c 100644
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@@ -5,7 +5,6 @@
 #include "s3.hh"
 #include "signals.hh"
 #include "compression.hh"
-#include "finally.hh"
 
 #if ENABLE_S3
 #include <aws/core/client/ClientConfiguration.h>
@@ -143,9 +142,9 @@ struct curlFileTransfer : public FileTransfer
 
                 if (successfulStatuses.count(getHTTPStatus()) && this->dataCallback) {
                     writtenToSink += realSize;
-                    dataCallback(*this, {(const char *) contents, realSize});
+                    dataCallback(*this, {static_cast<const char *>(contents), realSize});
                 } else {
-                    this->result.data.append((const char *) contents, realSize);
+                    this->result.data.append(static_cast<const char *>(contents), realSize);
                 }
 
                 return realSize;
@@ -157,13 +156,13 @@ struct curlFileTransfer : public FileTransfer
 
         static size_t writeCallbackWrapper(void * contents, size_t size, size_t nmemb, void * userp)
         {
-            return ((TransferItem *) userp)->writeCallback(contents, size, nmemb);
+            return static_cast<TransferItem *>(userp)->writeCallback(contents, size, nmemb);
         }
 
         size_t headerCallback(void * contents, size_t size, size_t nmemb)
         {
             size_t realSize = size * nmemb;
-            std::string line((char *) contents, realSize);
+            std::string line(static_cast<char *>(contents), realSize);
             printMsg(lvlVomit, "got header for '%s': %s", request.uri, trim(line));
 
             static std::regex statusLine("HTTP/[^ ]+ +[0-9]+(.*)", std::regex::extended | std::regex::icase);
@@ -204,7 +203,7 @@ struct curlFileTransfer : public FileTransfer
 
         static size_t headerCallbackWrapper(void * contents, size_t size, size_t nmemb, void * userp)
         {
-            return ((TransferItem *) userp)->headerCallback(contents, size, nmemb);
+            return static_cast<TransferItem *>(userp)->headerCallback(contents, size, nmemb);
         }
 
         int progressCallback(double dltotal, double dlnow)
@@ -219,7 +218,7 @@ struct curlFileTransfer : public FileTransfer
 
         static int progressCallbackWrapper(void * userp, double dltotal, double dlnow, double ultotal, double ulnow)
         {
-            return ((TransferItem *) userp)->progressCallback(dltotal, dlnow);
+            return static_cast<TransferItem *>(userp)->progressCallback(dltotal, dlnow);
         }
 
         static int debugCallback(CURL * handle, curl_infotype type, char * data, size_t size, void * userptr)
@@ -246,7 +245,7 @@ struct curlFileTransfer : public FileTransfer
 
         static size_t readCallbackWrapper(char *buffer, size_t size, size_t nitems, void * userp)
         {
-            return ((TransferItem *) userp)->readCallback(buffer, size, nitems);
+            return static_cast<TransferItem *>(userp)->readCallback(buffer, size, nitems);
         }
 
         void init()
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 8ea335551..af9c4ace1 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1318,7 +1318,7 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, std::string_view name
 
         auto *toRealloc = dumpBuffer.release();
         if (auto realloced = realloc(toRealloc, oldSize + want)) {
-            dumpBuffer.reset((char*) realloced);
+            dumpBuffer.reset(static_cast<char *>(realloced));
         } else {
             free(toRealloc);
             throw std::bad_alloc();
diff --git a/src/libutil/compression.cc b/src/libutil/compression.cc
index 773617031..6b0fa9d15 100644
--- a/src/libutil/compression.cc
+++ b/src/libutil/compression.cc
@@ -119,8 +119,8 @@ private:
 
     static ssize_t callback_write(struct archive * archive, void * _self, const void * buffer, size_t length)
     {
-        auto self = (ArchiveCompressionSink *) _self;
-        self->nextSink({(const char *) buffer, length});
+        auto self = static_cast<ArchiveCompressionSink *>(_self);
+        self->nextSink({static_cast<const char *>(buffer), length});
         return length;
     }
 };
@@ -160,7 +160,7 @@ struct BrotliDecompressionSource : Source
 
     size_t read(char * data, size_t len) override
     {
-        uint8_t * out = (uint8_t *) data;
+        uint8_t * out = reinterpret_cast<uint8_t *>(data);
         const auto * begin = out;
 
         while (len && !BrotliDecoderIsFinished(state.get())) {
@@ -172,7 +172,7 @@ struct BrotliDecompressionSource : Source
                 } catch (EndOfFile &) {
                     break;
                 }
-                next_in = (const uint8_t *) buf.get();
+                next_in = reinterpret_cast<const uint8_t *>(buf.get());
             }
 
             if (!BrotliDecoderDecompressStream(
@@ -238,7 +238,7 @@ struct BrotliCompressionSink : ChunkedCompressionSink
 
     void writeInternal(std::string_view data) override
     {
-        auto next_in = (const uint8_t *) data.data();
+        auto next_in = reinterpret_cast<const uint8_t *>(data.data());
         size_t avail_in = data.size();
         uint8_t * next_out = outbuf;
         size_t avail_out = sizeof(outbuf);
@@ -254,7 +254,7 @@ struct BrotliCompressionSink : ChunkedCompressionSink
                 throw CompressionError("error while compressing brotli compression");
 
             if (avail_out < sizeof(outbuf) || avail_in == 0) {
-                nextSink({(const char *) outbuf, sizeof(outbuf) - avail_out});
+                nextSink({reinterpret_cast<const char *>(outbuf), sizeof(outbuf) - avail_out});
                 next_out = outbuf;
                 avail_out = sizeof(outbuf);
             }
diff --git a/src/libutil/file-descriptor.cc b/src/libutil/file-descriptor.cc
index 037cd5297..7c82988b3 100644
--- a/src/libutil/file-descriptor.cc
+++ b/src/libutil/file-descriptor.cc
@@ -115,7 +115,7 @@ Generator<Bytes> drainFDSource(int fd, bool block)
                 throw SysError("reading from file");
         }
         else if (rd == 0) break;
-        else co_yield std::span{(char *) buf.data(), (size_t) rd};
+        else co_yield std::span{reinterpret_cast<char *>(buf.data()), (size_t) rd};
     }
 }
 
diff --git a/src/libutil/file-system.cc b/src/libutil/file-system.cc
index e2319ec59..631cf076b 100644
--- a/src/libutil/file-system.cc
+++ b/src/libutil/file-system.cc
@@ -567,9 +567,8 @@ Path createTempDir(const Path & tmpRoot, const Path & prefix,
 std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
 {
     Path tmpl(defaultTempDir() + "/" + prefix + ".XXXXXX");
-    // Strictly speaking, this is UB, but who cares...
     // FIXME: use O_TMPFILE.
-    AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
+    AutoCloseFD fd(mkstemp(tmpl.data()));
     if (!fd)
         throw SysError("creating temporary file '%s'", tmpl);
     closeOnExec(fd.get());
diff --git a/src/libutil/finally.hh b/src/libutil/finally.hh
index cbfd6195b..dc51d7b1e 100644
--- a/src/libutil/finally.hh
+++ b/src/libutil/finally.hh
@@ -22,7 +22,7 @@ public:
     Finally(Finally &&other) : fun(std::move(other.fun)) {
         other.movedFrom = true;
     }
-    ~Finally() noexcept(false)
+    ~Finally() noexcept(noexcept(fun()))
     {
         try {
             if (!movedFrom)
diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index 9eb332e78..925f71f80 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -129,7 +129,7 @@ std::string Hash::to_string(Base base, bool includeType) const
         break;
     case Base::Base64:
     case Base::SRI:
-        s += base64Encode(std::string_view((const char *) hash, hashSize));
+        s += base64Encode(std::string_view(reinterpret_cast<const char *>(hash), hashSize));
         break;
     }
     return s;
diff --git a/src/libutil/processes.cc b/src/libutil/processes.cc
index 866ba9647..61e1ad556 100644
--- a/src/libutil/processes.cc
+++ b/src/libutil/processes.cc
@@ -9,9 +9,7 @@
 #include <cerrno>
 #include <cstdlib>
 #include <cstring>
-#include <future>
 #include <iostream>
-#include <thread>
 
 #include <grp.h>
 #include <sys/types.h>
@@ -176,7 +174,7 @@ static pid_t doFork(std::function<void()> fun)
 #if __linux__
 static int childEntry(void * arg)
 {
-    auto main = (std::function<void()> *) arg;
+    auto main = static_cast<std::function<void()> *>(arg);
     (*main)();
     return 1;
 }
@@ -212,8 +210,8 @@ Pid startProcess(std::function<void()> fun, const ProcessOptions & options)
         assert(!(options.cloneFlags & CLONE_VM));
 
         size_t stackSize = 1 * 1024 * 1024;
-        auto stack = (char *) mmap(0, stackSize,
-            PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+        auto stack = static_cast<char *>(mmap(0, stackSize,
+            PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0));
         if (stack == MAP_FAILED) throw SysError("allocating stack");
 
         Finally freeStack([&]() { munmap(stack, stackSize); });
diff --git a/src/libutil/strings.cc b/src/libutil/strings.cc
index df48e9203..de9a0eb9f 100644
--- a/src/libutil/strings.cc
+++ b/src/libutil/strings.cc
@@ -8,7 +8,8 @@ namespace nix {
 std::vector<char *> stringsToCharPtrs(const Strings & ss)
 {
     std::vector<char *> res;
-    for (auto & s : ss) res.push_back((char *) s.c_str());
+    // This is const cast since this exists for OS APIs that want char *
+    for (auto & s : ss) res.push_back(const_cast<char *>(s.data()));
     res.push_back(0);
     return res;
 }
diff --git a/src/libutil/strings.hh b/src/libutil/strings.hh
index 03dff8160..7330e2063 100644
--- a/src/libutil/strings.hh
+++ b/src/libutil/strings.hh
@@ -20,6 +20,8 @@ constexpr char treeNull[] = "    ";
  * Convert a list of strings to a null-terminated vector of `char
  * *`s. The result must not be accessed beyond the lifetime of the
  * list of strings.
+ *
+ * Modifying the resulting array elements violates the constness of ss.
  */
 std::vector<char *> stringsToCharPtrs(const Strings & ss);
 
diff --git a/src/libutil/tarfile.cc b/src/libutil/tarfile.cc
index c7f9499fd..f024149ec 100644
--- a/src/libutil/tarfile.cc
+++ b/src/libutil/tarfile.cc
@@ -15,11 +15,11 @@ static int callback_open(struct archive *, void * self)
 
 static ssize_t callback_read(struct archive * archive, void * _self, const void * * buffer)
 {
-    auto self = (TarArchive *) _self;
+    auto self = static_cast<TarArchive *>(_self);
     *buffer = self->buffer.data();
 
     try {
-        return self->source->read((char *) self->buffer.data(), self->buffer.size());
+        return self->source->read(reinterpret_cast<char *>(self->buffer.data()), self->buffer.size());
     } catch (EndOfFile &) {
         return 0;
     } catch (std::exception & err) {
diff --git a/src/nix/daemon.cc b/src/nix/daemon.cc
index a9211d64a..ca65c38e6 100644
--- a/src/nix/daemon.cc
+++ b/src/nix/daemon.cc
@@ -316,7 +316,7 @@ static void daemonLoop(std::optional<TrustedFlag> forceTrustClientOpt)
             socklen_t remoteAddrLen = sizeof(remoteAddr);
 
             AutoCloseFD remote{accept(fdSocket.get(),
-                    (struct sockaddr *) &remoteAddr, &remoteAddrLen)};
+                    reinterpret_cast<struct sockaddr *>(&remoteAddr), &remoteAddrLen)};
             checkInterrupt();
             if (!remote) {
                 if (errno == EINTR) continue;
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 2f52a352f..981aa2fc5 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -1,5 +1,3 @@
-#include <algorithm>
-
 #include "args/root.hh"
 #include "command.hh"
 #include "common-args.hh"
@@ -62,12 +60,12 @@ static bool haveInternet()
     for (auto i = addrs; i; i = i->ifa_next) {
         if (!i->ifa_addr) continue;
         if (i->ifa_addr->sa_family == AF_INET) {
-            if (ntohl(((sockaddr_in *) i->ifa_addr)->sin_addr.s_addr) != INADDR_LOOPBACK) {
+            if (ntohl(reinterpret_cast<sockaddr_in *>(i->ifa_addr)->sin_addr.s_addr) != INADDR_LOOPBACK) {
                 return true;
             }
         } else if (i->ifa_addr->sa_family == AF_INET6) {
-            if (!IN6_IS_ADDR_LOOPBACK(&((sockaddr_in6 *) i->ifa_addr)->sin6_addr) &&
-                !IN6_IS_ADDR_LINKLOCAL(&((sockaddr_in6 *) i->ifa_addr)->sin6_addr))
+            if (!IN6_IS_ADDR_LOOPBACK(&reinterpret_cast<sockaddr_in6 *>(i->ifa_addr)->sin6_addr) &&
+                !IN6_IS_ADDR_LINKLOCAL(&reinterpret_cast<sockaddr_in6 *>(i->ifa_addr)->sin6_addr))
                 return true;
         }
     }
diff --git a/src/nix/why-depends.cc b/src/nix/why-depends.cc
index 5bef11c4d..6df84e9e4 100644
--- a/src/nix/why-depends.cc
+++ b/src/nix/why-depends.cc
@@ -171,7 +171,7 @@ struct CmdWhyDepends : SourceExprCommand, MixOperateOnOptions
            and `dependency`. */
         std::function<void(Node &, const std::string &, const std::string &)> printNode;
 
-        struct BailOut { };
+        struct BailOut : std::exception { };
 
         printNode = [&](Node & node, const std::string & firstPad, const std::string & tailPad) {
             auto pathS = store->printStorePath(node.path);
diff --git a/tests/unit/libstore/filetransfer.cc b/tests/unit/libstore/filetransfer.cc
index 6e8cf3bbe..71e7392fc 100644
--- a/tests/unit/libstore/filetransfer.cc
+++ b/tests/unit/libstore/filetransfer.cc
@@ -6,7 +6,6 @@
 #include <future>
 #include <gtest/gtest.h>
 #include <netinet/in.h>
-#include <stdexcept>
 #include <string>
 #include <string_view>
 #include <sys/poll.h>
@@ -130,7 +129,7 @@ serveHTTP(std::string status, std::string headers, std::function<std::string()>
 
 TEST(FileTransfer, exceptionAbortsDownload)
 {
-    struct Done
+    struct Done : std::exception
     {};
 
     auto ft = makeFileTransfer();
diff --git a/tests/unit/libutil/closure.cc b/tests/unit/libutil/closure.cc
index b4eaad6f9..8cac9a9fd 100644
--- a/tests/unit/libutil/closure.cc
+++ b/tests/unit/libutil/closure.cc
@@ -28,7 +28,7 @@ TEST(closure, correctClosure) {
 }
 
 TEST(closure, properlyHandlesDirectExceptions) {
-    struct TestExn {};
+    struct TestExn : std::exception {};
     EXPECT_THROW(
         computeClosure<string>(
             {"A"},
diff --git a/tests/unit/libutil/generator.cc b/tests/unit/libutil/generator.cc
index 800e6ca8a..22cc085f9 100644
--- a/tests/unit/libutil/generator.cc
+++ b/tests/unit/libutil/generator.cc
@@ -85,6 +85,7 @@ TEST(Generator, nestsExceptions)
         co_yield 1;
         co_yield []() -> Generator<int> {
             co_yield 9;
+            // NOLINTNEXTLINE(hicpp-exception-baseclass)
             throw 1;
             co_yield 10;
         }();
@@ -101,6 +102,7 @@ TEST(Generator, exception)
     {
         auto g = []() -> Generator<int> {
             co_yield 1;
+            // NOLINTNEXTLINE(hicpp-exception-baseclass)
             throw 1;
         }();
 
@@ -110,6 +112,7 @@ TEST(Generator, exception)
     }
     {
         auto g = []() -> Generator<int> {
+            // NOLINTNEXTLINE(hicpp-exception-baseclass)
             throw 1;
             co_return;
         }();
@@ -173,11 +176,13 @@ struct ThrowTransform
 
     int operator()(bool)
     {
+        // NOLINTNEXTLINE(hicpp-exception-baseclass)
         throw 2;
     }
 
     Generator<int, void> operator()(Generator<int> && inner)
     {
+        // NOLINTNEXTLINE(hicpp-exception-baseclass)
         throw false;
     }
 };
diff --git a/tests/unit/libutil/tests.cc b/tests/unit/libutil/tests.cc
index 9a44ad59b..29a5f7164 100644
--- a/tests/unit/libutil/tests.cc
+++ b/tests/unit/libutil/tests.cc
@@ -29,12 +29,12 @@ namespace nix {
         char cwd[PATH_MAX+1];
         auto p = absPath("");
 
-        ASSERT_EQ(p, getcwd((char*)&cwd, PATH_MAX));
+        ASSERT_EQ(p, getcwd(cwd, PATH_MAX));
     }
 
     TEST(absPath, usesOptionalBasePathWhenGiven) {
         char _cwd[PATH_MAX+1];
-        char* cwd = getcwd((char*)&_cwd, PATH_MAX);
+        char* cwd = getcwd(_cwd, PATH_MAX);
 
         auto p = absPath("", cwd);
 
@@ -43,7 +43,7 @@ namespace nix {
 
     TEST(absPath, isIdempotent) {
         char _cwd[PATH_MAX+1];
-        char* cwd = getcwd((char*)&_cwd, PATH_MAX);
+        char* cwd = getcwd(_cwd, PATH_MAX);
         auto p1 = absPath(cwd);
         auto p2 = absPath(p1);