clang-tidy: drop redundant casts

Found via `readability-redundant-casting`. Prone to false positives, not
enabled.

Ref: https://clang.llvm.org/extra/clang-tidy/checks/readability/redundant-casting.html

Closes #20630

docs/examples/chkspeed.c

@@ -63,7 +63,7 @@ static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data)
      so we only return the size we would have saved ... */
   (void)ptr;
   (void)data;
-  return (size_t)(size * nmemb);
+  return size * nmemb;
 }
 
 int main(int argc, const char *argv[])

docs/examples/ftpgetinfo.c

@@ -42,7 +42,7 @@ static size_t throw_away(void *ptr, size_t size, size_t nmemb, void *data)
   (void)data;
   /* we are not interested in the headers itself,
      so we only return the size we would have saved ... */
-  return (size_t)(size * nmemb);
+  return size * nmemb;
 }
 
 int main(void)

lib/cshutdn.c

@@ -50,7 +50,7 @@ static void cshutdn_run_conn_handler(struct Curl_easy *data,
        * default 120 seconds. */
       if(data->state.internal) {
         data->set.timeout = DEFAULT_SHUTDOWN_TIMEOUT_MS;
-        (void)Curl_pgrsTime(data, TIMER_STARTOP);
+        Curl_pgrsTime(data, TIMER_STARTOP);
       }
 
       /* This is set if protocol-specific cleanups should be made */

lib/curl_fnmatch.c

@@ -251,8 +251,8 @@ fail:
 static int loop(const unsigned char *pattern, const unsigned char *string,
                 int maxstars)
 {
-  const unsigned char *p = (const unsigned char *)pattern;
-  const unsigned char *s = (const unsigned char *)string;
+  const unsigned char *p = pattern;
+  const unsigned char *s = string;
   unsigned char charset[CURLFNM_CHSET_SIZE] = { 0 };
 
   for(;;) {

lib/doh.c

@@ -980,7 +980,7 @@ static CURLcode doh2ai(const struct dohentry *de, const char *hostname,
       addr = (void *)ai->ai_addr; /* storage area for this info */
       DEBUGASSERT(sizeof(struct in_addr) == sizeof(de->addr[i].ip.v4));
       memcpy(&addr->sin_addr, &de->addr[i].ip.v4, sizeof(struct in_addr));
-      addr->sin_family = (CURL_SA_FAMILY_T)addrtype;
+      addr->sin_family = addrtype;
       addr->sin_port = htons((unsigned short)port);
       break;
 
@@ -989,7 +989,7 @@ static CURLcode doh2ai(const struct dohentry *de, const char *hostname,
       addr6 = (void *)ai->ai_addr; /* storage area for this info */
       DEBUGASSERT(sizeof(struct in6_addr) == sizeof(de->addr[i].ip.v6));
       memcpy(&addr6->sin6_addr, &de->addr[i].ip.v6, sizeof(struct in6_addr));
-      addr6->sin6_family = (CURL_SA_FAMILY_T)addrtype;
+      addr6->sin6_family = addrtype;
       addr6->sin6_port = htons((unsigned short)port);
       break;
 #endif

lib/hash.c

@@ -177,7 +177,7 @@ void *Curl_hash_add2(struct Curl_hash *h, void *key, size_t key_len, void *p,
     if(h->comp_func(he->key, he->key_len, key, key_len)) {
       /* existing key entry, overwrite by clearing old pointer */
       hash_elem_clear_ptr(h, he);
-      he->ptr = (void *)p;
+      he->ptr = p;
       he->dtor = dtor;
       return p;
     }

lib/http.c

@@ -3740,12 +3740,12 @@ static CURLcode http_statusline(struct Curl_easy *data,
 
   data->info.httpcode = k->httpcode;
   data->info.httpversion = k->httpversion;
-  conn->httpversion_seen = (unsigned char)k->httpversion;
+  conn->httpversion_seen = k->httpversion;
 
   if(!data->state.http_neg.rcvd_min ||
      data->state.http_neg.rcvd_min > k->httpversion)
     /* store the lowest server version we encounter */
-    data->state.http_neg.rcvd_min = (unsigned char)k->httpversion;
+    data->state.http_neg.rcvd_min = k->httpversion;
 
   /*
    * This code executes as part of processing the header. As a

lib/ldap.c

@@ -416,7 +416,7 @@ static CURLcode ldap_do(struct Curl_easy *data, bool *done)
 
   Curl_pgrsReset(data);
   rc = ldap_search_s(server, ludp->lud_dn,
-                     (curl_ldap_num_t)ludp->lud_scope,
+                     ludp->lud_scope,
                      ludp->lud_filter, ludp->lud_attrs, 0, &ldapmsg);
 
   if(rc != LDAP_SUCCESS && rc != LDAP_SIZELIMIT_EXCEEDED) {

lib/mprintf.c

@@ -1049,7 +1049,7 @@ static int formatf(void *userp, /* untouched by format(), just sent to the
         if(p.flags & FLAGS_LONG)
           *(long *)iptr->val.ptr = (long)done;
       else if(!(p.flags & FLAGS_SHORT))
-        *(int *)iptr->val.ptr = (int)done;
+        *(int *)iptr->val.ptr = done;
       else
         *(short *)iptr->val.ptr = (short)done;
       break;

lib/multi.c

@@ -2495,7 +2495,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
 
       /* after init, go SETUP */
       multistate(data, MSTATE_SETUP);
-      (void)Curl_pgrsTime(data, TIMER_STARTOP);
+      Curl_pgrsTime(data, TIMER_STARTOP);
       FALLTHROUGH();
 
     case MSTATE_SETUP:

lib/socks_sspi.c

@@ -539,7 +539,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
   else {
     if(sspi_w_token[0].cbBuffer != 1) {
       failf(data, "Invalid SSPI encryption response length (%lu).",
-            (unsigned long)sspi_w_token[0].cbBuffer);
+            sspi_w_token[0].cbBuffer);
       result = CURLE_COULDNT_CONNECT;
       goto error;
     }

lib/url.c

@@ -3023,7 +3023,7 @@ static CURLcode parse_connect_to_slist(struct Curl_easy *data,
       }
     }
     else if(hit) {
-      char *hostd = curlx_strdup((char *)as->dst.host);
+      char *hostd = curlx_strdup(as->dst.host);
       if(!hostd)
         return CURLE_OUT_OF_MEMORY;
       conn->conn_to_host.rawalloc = hostd;

lib/version.c

@@ -652,7 +652,7 @@ curl_version_info_data *curl_version_info(CURLversion stamp)
 #endif
 
 #ifdef HAVE_ZSTD
-  version_info.zstd_ver_num = (unsigned int)ZSTD_versionNumber();
+  version_info.zstd_ver_num = ZSTD_versionNumber();
   zstd_version(zstd_buffer, sizeof(zstd_buffer));
   version_info.zstd_version = zstd_buffer;
 #endif

lib/vquic/curl_ngtcp2.c

@@ -1824,7 +1824,7 @@ static CURLcode cf_ngtcp2_recv_pkts(const unsigned char *buf, size_t buflen,
     CURL_TRC_CF(pktx->data, pktx->cf, "vquic_recv(len=%zu, gso=%zu, ecn=%x)",
                 buflen, gso_size, ecn);
   ngtcp2_addr_init(&path.local, (struct sockaddr *)&ctx->q.local_addr,
-                   (socklen_t)ctx->q.local_addrlen);
+                   ctx->q.local_addrlen);
   ngtcp2_addr_init(&path.remote, (struct sockaddr *)remote_addr,
                    remote_addrlen);
   pi.ecn = (uint8_t)ecn;

lib/vssh/libssh.c

@@ -152,7 +152,7 @@ static int myssh_is_known(struct Curl_easy *data, struct ssh_conn *sshc)
     }
 
     for(i = 0; i < 16; i++)
-      curl_msnprintf(&md5buffer[i * 2], 3, "%02x", (unsigned char)hash[i]);
+      curl_msnprintf(&md5buffer[i * 2], 3, "%02x", hash[i]);
 
     infof(data, "SSH MD5 fingerprint: %s", md5buffer);
 
@@ -1168,7 +1168,7 @@ static int myssh_in_SFTP_DOWNLOAD_STAT(struct Curl_easy *data,
   if(data->state.resume_from) {
     if(data->state.resume_from < 0) {
       /* We are supposed to download the last abs(from) bytes */
-      if((curl_off_t)size < -data->state.resume_from) {
+      if(size < -data->state.resume_from) {
         failf(data, "Offset (%" FMT_OFF_T ") was beyond file size (%"
               FMT_OFF_T ")", data->state.resume_from, size);
         return myssh_to_ERROR(data, sshc, CURLE_BAD_DOWNLOAD_RESUME);
@@ -1177,7 +1177,7 @@ static int myssh_in_SFTP_DOWNLOAD_STAT(struct Curl_easy *data,
       data->state.resume_from += size;
     }
     else {
-      if((curl_off_t)size < data->state.resume_from) {
+      if(size < data->state.resume_from) {
         failf(data, "Offset (%" FMT_OFF_T
               ") was beyond file size (%" FMT_OFF_T ")",
               data->state.resume_from, size);
@@ -1732,7 +1732,7 @@ static int myssh_SSH_SCP_DOWNLOAD(struct Curl_easy *data,
 
   /* download data */
   bytecount = ssh_scp_request_get_size(sshc->scp_session);
-  data->req.maxdownload = (curl_off_t)bytecount;
+  data->req.maxdownload = bytecount;
   Curl_xfer_setup_recv(data, FIRSTSOCKET, bytecount);
 
   /* not set by Curl_xfer_setup to preserve keepon bits */

lib/vssh/libssh2.c

@@ -3218,7 +3218,7 @@ static ssize_t ssh_tls_recv(libssh2_socket_t sock, void *buffer,
     return -EAGAIN; /* magic return code for libssh2 */
   else if(result)
     return -1; /* generic error */
-  Curl_debug(data, CURLINFO_DATA_IN, (const char *)buffer, (size_t)nread);
+  Curl_debug(data, CURLINFO_DATA_IN, (const char *)buffer, nread);
   return (ssize_t)nread;
 }
 
@@ -3791,7 +3791,7 @@ CURLcode Curl_ssh_init(void)
 
 void Curl_ssh_cleanup(void)
 {
-  (void)libssh2_exit();
+  libssh2_exit();
 }
 
 void Curl_ssh_version(char *buffer, size_t buflen)

lib/vtls/openssl.c

@@ -3451,7 +3451,7 @@ ossl_init_session_and_alpns(struct ossl_ctx *octx,
       failf(data, "Error determining ALPN");
       return CURLE_SSL_CONNECT_ERROR;
     }
-    if(SSL_set_alpn_protos(octx->ssl, proto.data, (int)proto.len)) {
+    if(SSL_set_alpn_protos(octx->ssl, proto.data, proto.len)) {
       failf(data, "Error setting ALPN");
       return CURLE_SSL_CONNECT_ERROR;
     }
@@ -5157,7 +5157,7 @@ static CURLcode ossl_recv(struct Curl_cfilter *cf,
     *pnread = (size_t)nread;
   else {
     /* failed SSL_read */
-    int err = SSL_get_error(octx->ssl, (int)nread);
+    int err = SSL_get_error(octx->ssl, nread);
 
     switch(err) {
     case SSL_ERROR_NONE: /* this is not an error */

lib/vtls/schannel.c

@@ -610,8 +610,7 @@ static CURLcode acquire_sspi_handle(struct Curl_cfilter *cf,
     credentials.dwVersion = SCH_CREDENTIALS_VERSION;
     credentials.dwFlags = flags | SCH_USE_STRONG_CRYPTO;
 
-    credentials.pTlsParameters->grbitDisabledProtocols =
-      (DWORD)~enabled_protocols;
+    credentials.pTlsParameters->grbitDisabledProtocols = ~enabled_protocols;
 
     if(client_certs[0]) {
       credentials.cCreds = 1;

src/config2setopts.c

@@ -48,7 +48,7 @@ static int get_address_family(curl_socket_t sockfd)
   struct sockaddr addr;
   curl_socklen_t addrlen = sizeof(addr);
   memset(&addr, 0, sizeof(addr));
-  if(getsockname(sockfd, (struct sockaddr *)&addr, &addrlen) == 0)
+  if(getsockname(sockfd, &addr, &addrlen) == 0)
     return addr.sa_family;
   return AF_UNSPEC;
 }

src/tool_cb_hdr.c

@@ -432,7 +432,7 @@ size_t tool_header_cb(char *ptr, size_t size, size_t nmemb, void *userdata)
   struct OutStruct *etag_save = &per->etag_save;
   const char *str = ptr;
   const size_t cb = size * nmemb;
-  const char *end = (char *)ptr + cb;
+  const char *end = ptr + cb;
   const char *scheme = NULL;
 
   if(!per->config)

src/tool_cb_prg.c

@@ -113,7 +113,7 @@ static void update_width(struct ProgressData *bar)
   if(cols > MAX_BARLENGTH)
     bar->width = MAX_BARLENGTH;
   else if(cols > MIN_BARLENGTH)
-    bar->width = (int)cols;
+    bar->width = cols;
   else
     bar->width = MIN_BARLENGTH;
 }

src/tool_cb_rea.c

@@ -49,7 +49,7 @@ static bool waitfd(int waitms, int fd)
   set.fd = fd;
   set.events = POLLIN;
   set.revents = 0;
-  if(poll(&set, 1, (int)waitms))
+  if(poll(&set, 1, waitms))
     return TRUE; /* timeout */
   return FALSE;
 #else

src/tool_filetime.c

@@ -108,8 +108,7 @@ void setfiletime(curl_off_t filetime, const char *filename)
                            FILE_SHARE_READ | FILE_SHARE_WRITE |
                            FILE_SHARE_DELETE, NULL, OPEN_EXISTING, 0, NULL);
   if(hfile != INVALID_HANDLE_VALUE) {
-    curl_off_t converted = ((curl_off_t)filetime * 10000000) +
-      116444736000000000;
+    curl_off_t converted = (filetime * 10000000) + 116444736000000000;
     FILETIME ft;
     ft.dwLowDateTime = (DWORD)(converted & 0xFFFFFFFF);
     ft.dwHighDateTime = (DWORD)(converted >> 32);

tests/libtest/cli_hx_download.c

@@ -120,7 +120,7 @@ static size_t my_write_d_cb(char *buf, size_t nitems, size_t buflen,
     return CURL_WRITEFUNC_ERROR;
   }
 
-  return (size_t)nwritten;
+  return nwritten;
 }
 
 static int my_progress_d_cb(void *userdata,
@@ -220,7 +220,7 @@ static int my_progress_d_cb(void *userdata,
 #endif
       default:
         curl_mfprintf(stderr, "[t-%zu] info SSL_PTR backend=%d, ptr=%p\n",
-                      t->idx, tls->backend, (void *)tls->internals);
+                      t->idx, tls->backend, tls->internals);
         break;
       }
     }

tests/libtest/cli_hx_upload.c

@@ -85,7 +85,7 @@ static size_t my_write_u_cb(char *buf, size_t nitems, size_t buflen,
     return 0;
   }
   t->recv_size += (curl_off_t)nwritten;
-  return (size_t)nwritten;
+  return nwritten;
 }
 
 static size_t my_read_cb(char *buf, size_t nitems, size_t buflen,
@@ -122,7 +122,7 @@ static size_t my_read_cb(char *buf, size_t nitems, size_t buflen,
                   "%" CURL_FORMAT_CURL_OFF_T " bytes\n", t->idx, t->send_size);
     return CURL_READFUNC_ABORT;
   }
-  return (size_t)nread;
+  return nread;
 }
 
 static int my_progress_u_cb(void *userdata,

tests/libtest/lib2301.c

@@ -51,7 +51,7 @@ static size_t t2301_write_cb(char *b, size_t size, size_t nitems, void *p)
   curl_mfprintf(stderr, "Called CURLOPT_WRITEFUNCTION with %zu bytes: ",
                 nitems);
   for(i = 0; i < nitems; i++)
-    curl_mfprintf(stderr, "%02x ", (unsigned char)buffer[i]);
+    curl_mfprintf(stderr, "%02x ", buffer[i]);
   curl_mfprintf(stderr, "\n");
   (void)size;
   if(buffer[0] == 0x89) {

tests/libtest/lib573.c

@@ -41,7 +41,7 @@ static CURLcode test_lib573(const char *URL)
   dbl_epsilon = 1.0;
   do {
     dbl_epsilon /= 2.0;
-  } while((double)(1.0 + (dbl_epsilon / 2.0)) > (double)1.0);
+  } while((1.0 + (dbl_epsilon / 2.0)) > 1.0);
 
   start_test_timing();
 

tests/unit/unit1661.c

@@ -93,7 +93,7 @@ static CURLcode test_unit1661(const char *arg)
   abort_unless(result == CURLE_OK, curl_easy_strerror(result));
   fail_unless(freecount == 1, "Destructor not called");
   fail_unless((const char *)bufref.ptr != buffer, "Returned pointer not set");
-  buffer = (const char *)Curl_bufref_ptr(&bufref);
+  buffer = Curl_bufref_ptr(&bufref);
   fail_unless(buffer, "Allocated pointer is NULL");
   fail_unless(bufref.len == 3, "Wrong data size stored");
   if(buffer) {

tests/unit/unit2603.c

@@ -80,7 +80,7 @@ static void parse_success(const struct tcase *t)
       curl_mfprintf(stderr, "got result %d parsing: '%s'\n", result, buf);
       fail("error consuming");
     }
-    in_consumed += (size_t)nread;
+    in_consumed += nread;
     if(nread != buflen) {
       if(!p.done) {
         curl_mfprintf(stderr, "only %zd/%zu consumed for: '%s'\n",