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

3 files changed, 5 insertions, 7 deletions

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);