diff --git a/glib/gdate.c b/glib/gdate.c
index b867ba9db..737fa54fd 100644
--- a/glib/gdate.c
+++ b/glib/gdate.c
@@ -1142,7 +1142,8 @@ g_date_prepare_to_parse (const gchar      *str,
               dmy_order[i] = G_DATE_DAY;
               break;
             case 76:
-              using_twodigit_years = TRUE; /* FALL THRU */
+              using_twodigit_years = TRUE;
+              G_GNUC_FALLTHROUGH;
             case 1976:
               dmy_order[i] = G_DATE_YEAR;
               break;
diff --git a/glib/gscanner.c b/glib/gscanner.c
index e093bb8bf..e2c6aa4c4 100644
--- a/glib/gscanner.c
+++ b/glib/gscanner.c
@@ -1955,7 +1955,7 @@ g_scanner_get_token_ll	(GScanner	*scanner,
 	    }
 	  else
 	    ch = '0';
-	  /* fall through */
+          G_GNUC_FALLTHROUGH;
 	case '1':
 	case '2':
 	case '3':
diff --git a/glib/gshell.c b/glib/gshell.c
index 0c6dc85f1..afdc04671 100644
--- a/glib/gshell.c
+++ b/glib/gshell.c
@@ -523,7 +523,7 @@ tokenize_command_line (const gchar *command_line,
               ensure_token (&current_token);
               g_string_append_c (current_token, *p);
 
-              /* FALL THRU */
+              G_GNUC_FALLTHROUGH;
             case '\\':
               current_quote = *p;
               break;
diff --git a/glib/gslice.c b/glib/gslice.c
index 4c758c3be..13479955a 100644
--- a/glib/gslice.c
+++ b/glib/gslice.c
@@ -310,6 +310,7 @@ g_slice_set_config (GSliceConfig ckey,
       break;
     case G_SLICE_CONFIG_COLOR_INCREMENT:
       slice_config.color_increment = value;
+      break;
     default: ;
     }
 }
diff --git a/glib/gspawn.c b/glib/gspawn.c
index 85813ef00..6832ae0b9 100644
--- a/glib/gspawn.c
+++ b/glib/gspawn.c
@@ -2255,8 +2255,7 @@ g_execute (const gchar *file,
                */
 	      got_eacces = TRUE;
 
-              /* FALL THRU */
-              
+              G_GNUC_FALLTHROUGH;
 	    case ENOENT:
 #ifdef ESTALE
 	    case ESTALE:
diff --git a/glib/gvariant.c b/glib/gvariant.c
index ee1a9c020..1e524801a 100644
--- a/glib/gvariant.c
+++ b/glib/gvariant.c
@@ -4466,7 +4466,7 @@ g_variant_check_format_string (GVariant    *value,
               return FALSE;
             }
 
-          /* fall through */
+          G_GNUC_FALLTHROUGH;
         case '^':
         case '@':
           /* ignore these 2 (or 3) */
@@ -4487,7 +4487,7 @@ g_variant_check_format_string (GVariant    *value,
           if (*type_string != '(')
             return FALSE;
 
-          /* fall through */
+          G_GNUC_FALLTHROUGH;
         case '*':
           /* consume a full type string for the '*' or 'r' */
           if (!g_variant_type_string_scan (type_string, NULL, &type_string))