diff --git a/lib/formdata.c b/lib/formdata.c
index c214ba28e..3626f562f 100644
--- a/lib/formdata.c
+++ b/lib/formdata.c
@@ -342,6 +342,7 @@ CURLFORMcode FormAdd(struct curl_httppost **httppost,
 #else
       current_form->flags |= HTTPPOST_PTRNAME; /* fall through */
 #endif
+      /* FALLTHROUGH */
     case CURLFORM_COPYNAME:
       if(current_form->name)
         return_value = CURL_FORMADD_OPTION_TWICE;
diff --git a/lib/ftp.c b/lib/ftp.c
index 867c97994..a1546a135 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -3214,6 +3214,7 @@ static CURLcode ftp_done(struct connectdata *conn, CURLcode status,
 
     /* until we cope better with prematurely ended requests, let them
      * fallback as if in complete failure */
+    /* FALLTHROUGH */
   default:       /* by default, an error means the control connection is
                     wedged and should not be used anymore */
     ftpc->ctl_valid = FALSE;
diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index eb625fe93..20626fec9 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -539,6 +539,7 @@ int cert_stuff(struct connectdata *conn,
       if(!key_file)
         /* cert & key can only be in PEM case in the same file */
         key_file=cert_file;
+      /* FALLTHROUGH */
     case SSL_FILETYPE_ASN1:
       if(SSL_CTX_use_PrivateKey_file(ctx, key_file, file_type) != 1) {
         failf(data, "unable to set private key file: '%s' type %s",
diff --git a/src/tool_cb_dbg.c b/src/tool_cb_dbg.c
index 8e81f1be3..f4252ad88 100644
--- a/src/tool_cb_dbg.c
+++ b/src/tool_cb_dbg.c
@@ -185,6 +185,7 @@ int tool_debug_cb(CURL *handle, curl_infotype type,
   switch(type) {
   case CURLINFO_TEXT:
     fprintf(output, "%s== Info: %s", timebuf, data);
+    /* FALLTHROUGH */
   default: /* in case a new one is introduced to shock us */
     return 0;