[regexp] Mark functions MUST_USE_RESULT

src/regexp/regexp-utils.h

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_REGEXP_REGEXP_UTILS_H_
 #define V8_REGEXP_REGEXP_UTILS_H_
 
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 // Helper methods for C++ regexp builtins.
 class RegExpUtils : public AllStatic {
  public:
   // Last match info accessors.
   static Handle<String> GenericCaptureGetter(Isolate* isolate,
                                              Handle<RegExpMatchInfo> match_info,
                                              int capture, bool* ok = nullptr);
 
   // Last index (RegExp.lastIndex) accessors.
-  static MaybeHandle<Object> SetLastIndex(Isolate* isolate,
-                                          Handle<JSReceiver> regexp, int value);
-  static MaybeHandle<Object> GetLastIndex(Isolate* isolate,
-                                          Handle<JSReceiver> recv);
+  static MUST_USE_RESULT MaybeHandle<Object> SetLastIndex(
+      Isolate* isolate, Handle<JSReceiver> regexp, int value);
+  static MUST_USE_RESULT MaybeHandle<Object> GetLastIndex(
+      Isolate* isolate, Handle<JSReceiver> recv);
 
   // ES#sec-regexpexec Runtime Semantics: RegExpExec ( R, S )
-  static MaybeHandle<Object> RegExpExec(Isolate* isolate,
-                                        Handle<JSReceiver> regexp,
-                                        Handle<String> string,
-                                        Handle<Object> exec);
+  static MUST_USE_RESULT MaybeHandle<Object> RegExpExec(
+      Isolate* isolate, Handle<JSReceiver> regexp, Handle<String> string,
+      Handle<Object> exec);
 
   // ES#sec-isregexp IsRegExp ( argument )
   // Includes checking of the match property.
   static Maybe<bool> IsRegExp(Isolate* isolate, Handle<Object> object);
 
   // Checks whether the given object is an unmodified JSRegExp instance.
   // Neither the object's map, nor its prototype's map may be modified.
   static bool IsUnmodifiedRegExp(Isolate* isolate, Handle<Object> obj);
 
   // ES#sec-advancestringindex
   // AdvanceStringIndex ( S, index, unicode )
   static int AdvanceStringIndex(Isolate* isolate, Handle<String> string,
                                 int index, bool unicode);
-  static MaybeHandle<Object> SetAdvancedStringIndex(Isolate* isolate,
-                                                    Handle<JSReceiver> regexp,
-                                                    Handle<String> string,
-                                                    bool unicode);
+  static MUST_USE_RESULT MaybeHandle<Object> SetAdvancedStringIndex(
+      Isolate* isolate, Handle<JSReceiver> regexp, Handle<String> string,
+      bool unicode);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGEXP_REGEXP_UTILS_H_