diff --git a/lib/util/json.c b/lib/util/json.c
index 266129dca..7279fb85f 100644
--- a/lib/util/json.c
+++ b/lib/util/json.c
@@ -156,7 +156,7 @@ json_append_string(struct json_container *jsonc, const char *str)
 	    break;
 	}
 	*cp++ = ch;
-	*cp++ = '\0';
+	*cp = '\0';
 	if (!json_append_buf(jsonc, buf))
 		debug_return_bool(false);
     }
diff --git a/plugins/group_file/getgrent.c b/plugins/group_file/getgrent.c
index 5107acef2..f37fb0ec2 100644
--- a/plugins/group_file/getgrent.c
+++ b/plugins/group_file/getgrent.c
@@ -150,7 +150,7 @@ next_entry:
 	    gr.gr_mem[n] = cp;
 	    cp = strtok_r(NULL, ",", &last);
 	}
-	gr.gr_mem[n++] = NULL;
+	gr.gr_mem[n] = NULL;
     } else
 	gr.gr_mem = NULL;
     return &gr;
diff --git a/plugins/sudoers/cvtsudoers_merge.c b/plugins/sudoers/cvtsudoers_merge.c
index bd62cc068..3afd5db90 100644
--- a/plugins/sudoers/cvtsudoers_merge.c
+++ b/plugins/sudoers/cvtsudoers_merge.c
@@ -328,7 +328,7 @@ alias_make_unique(const char *old_name, int type,
     struct sudoers_parse_tree *parse_tree0,
     struct sudoers_parse_tree *merged_tree)
 {
-    struct sudoers_parse_tree *parse_tree = parse_tree0;
+    struct sudoers_parse_tree *parse_tree;
     char *cp, *new_name = NULL;
     struct alias *a;
     long long suffix;
diff --git a/plugins/sudoers/env.c b/plugins/sudoers/env.c
index 887d6468f..225c536f2 100644
--- a/plugins/sudoers/env.c
+++ b/plugins/sudoers/env.c
@@ -692,7 +692,7 @@ matches_env_check(const char *var, bool *full_match)
 	} else {
 	    const char *val = strchr(var, '=');
 	    if (val != NULL)
-		keepit = !strpbrk(++val, "/%");
+		keepit = !strpbrk(val + 1, "/%");
 	}
     }
     debug_return_int(keepit);
diff --git a/plugins/sudoers/iolog.c b/plugins/sudoers/iolog.c
index fc1bc7d11..ec93698f4 100644
--- a/plugins/sudoers/iolog.c
+++ b/plugins/sudoers/iolog.c
@@ -787,10 +787,8 @@ sudoers_io_open(unsigned int version, sudo_conv_t conversation,
 	}
     }
 
-    if (!sudoers_debug_register(plugin_path, &debug_files)) {
-	ret = -1;
+    if (!sudoers_debug_register(plugin_path, &debug_files))
 	goto done;
-    }
 
     /* If we have no command (because -V was specified) just return. */
     if (argc == 0)
diff --git a/plugins/sudoers/ldap.c b/plugins/sudoers/ldap.c
index 22c81db94..90aa35eae 100644
--- a/plugins/sudoers/ldap.c
+++ b/plugins/sudoers/ldap.c
@@ -204,7 +204,7 @@ static int
 sudo_ldap_init(LDAP **ldp, const char *host, int port)
 {
     LDAP *ld;
-    int ret = LDAP_CONNECT_ERROR;
+    int ret;
     debug_decl(sudo_ldap_init, SUDOERS_DEBUG_LDAP);
 
 #ifdef HAVE_LDAPSSL_INIT
@@ -281,8 +281,10 @@ sudo_ldap_init(LDAP **ldp, const char *host, int port)
 	ret = ldap_set_option(ld, LDAP_OPT_HOST_NAME, host);
 #else
 	DPRINTF2("ldap_init(%s, %d)", host, port);
-	if ((ld = ldap_init((char *)host, port)) == NULL)
+	if ((ld = ldap_init((char *)host, port)) == NULL) {
+	    ret = LDAP_LOCAL_ERROR;
 	    goto done;
+	}
 	ret = LDAP_SUCCESS;
 #endif
     }
diff --git a/plugins/sudoers/ldap_conf.c b/plugins/sudoers/ldap_conf.c
index 7e4a2e3ad..2b566dd0e 100644
--- a/plugins/sudoers/ldap_conf.c
+++ b/plugins/sudoers/ldap_conf.c
@@ -509,7 +509,7 @@ sudo_krb5_ccname_path(const char *old_ccname)
 static bool
 sudo_check_krb5_ccname(const char *ccname)
 {
-    int fd = -1;
+    int fd;
     const char *ccname_path;
     debug_decl(sudo_check_krb5_ccname, SUDOERS_DEBUG_LDAP);
 
diff --git a/plugins/sudoers/log_client.c b/plugins/sudoers/log_client.c
index a53ffe427..783d1ff70 100644
--- a/plugins/sudoers/log_client.c
+++ b/plugins/sudoers/log_client.c
@@ -1085,7 +1085,7 @@ done:
 static bool
 fmt_initial_message(struct client_closure *closure)
 {
-    bool ret = true;
+    bool ret = false;
     debug_decl(fmt_initial_message, SUDOERS_DEBUG_UTIL);
 
     closure->state = closure->initial_state;
@@ -1116,7 +1116,6 @@ fmt_initial_message(struct client_closure *closure)
 	break;
     default:
 	sudo_warnx(U_("%s: unexpected state %d"), __func__, closure->state);
-	ret = false;
 	break;
     }
     debug_return_bool(ret);
diff --git a/plugins/sudoers/match_command.c b/plugins/sudoers/match_command.c
index 37d376d32..120dfa5ed 100644
--- a/plugins/sudoers/match_command.c
+++ b/plugins/sudoers/match_command.c
@@ -185,7 +185,7 @@ static bool
 open_cmnd(const char *path, const char *runchroot,
     const struct command_digest_list *digests, int *fdp)
 {
-    int fd = -1;
+    int fd;
     char pathbuf[PATH_MAX];
     debug_decl(open_cmnd, SUDOERS_DEBUG_MATCH);
 
diff --git a/plugins/sudoers/strvec_join.c b/plugins/sudoers/strvec_join.c
index 240e0938c..ae209eb91 100644
--- a/plugins/sudoers/strvec_join.c
+++ b/plugins/sudoers/strvec_join.c
@@ -68,7 +68,7 @@ strvec_join(char *const argv[], char sep, size_t (*cpy)(char *, const char *, si
 	*dst++ = sep;
 	size--;
     }
-    *--dst = '\0';
+    dst[-1] = '\0';
 
     debug_return_str(result);
 }
diff --git a/plugins/sudoers/tsgetgrpw.c b/plugins/sudoers/tsgetgrpw.c
index 9daa3e2eb..19fb798c4 100644
--- a/plugins/sudoers/tsgetgrpw.c
+++ b/plugins/sudoers/tsgetgrpw.c
@@ -300,7 +300,7 @@ next_entry:
 	    gr.gr_mem[n] = cp;
 	    cp = strtok_r(NULL, ",", &last);
 	}
-	gr.gr_mem[n++] = NULL;
+	gr.gr_mem[n] = NULL;
     } else
 	gr.gr_mem = NULL;
     return &gr;
diff --git a/plugins/sudoers/visudo.c b/plugins/sudoers/visudo.c
index 734118bac..7636b9754 100644
--- a/plugins/sudoers/visudo.c
+++ b/plugins/sudoers/visudo.c
@@ -540,7 +540,7 @@ edit_sudoers(struct sudoersfile *sp, char *editor, int editor_argc,
     }
     editor_argv[ac++] = (char *)"--";
     editor_argv[ac++] = sp->tpath;
-    editor_argv[ac++] = NULL;
+    editor_argv[ac] = NULL;
 
     /*
      * Do the edit:
diff --git a/src/sudo.c b/src/sudo.c
index 2888d23a5..2405cb0f3 100644
--- a/src/sudo.c
+++ b/src/sudo.c
@@ -355,7 +355,7 @@ os_init_common(int argc, char *argv[], char *envp[])
 static void
 fix_fds(void)
 {
-    int miss[3], devnull = -1;
+    int miss[3];
     debug_decl(fix_fds, SUDO_DEBUG_UTIL);
 
     /*
@@ -366,7 +366,8 @@ fix_fds(void)
     miss[STDOUT_FILENO] = fcntl(STDOUT_FILENO, F_GETFL, 0) == -1;
     miss[STDERR_FILENO] = fcntl(STDERR_FILENO, F_GETFL, 0) == -1;
     if (miss[STDIN_FILENO] || miss[STDOUT_FILENO] || miss[STDERR_FILENO]) {
-	devnull = open(_PATH_DEVNULL, O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
+	int devnull =
+	    open(_PATH_DEVNULL, O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
 	if (devnull == -1)
 	    sudo_fatal(U_("unable to open %s"), _PATH_DEVNULL);
 	if (miss[STDIN_FILENO] && dup2(devnull, STDIN_FILENO) == -1)
@@ -1105,7 +1106,7 @@ format_plugin_settings(struct plugin_container *plugin)
 		goto bad;
 	}
     }
-    plugin_settings[++i] = NULL;
+    plugin_settings[i + 1] = NULL;
 
     /* Add to list of vectors to be garbage collected at exit. */
     if (!gc_add(GC_VECTOR, plugin_settings))