diff --git a/js/src/js.msg b/js/src/js.msg
index d8b89879c90f..cb73d2b69596 100644
--- a/js/src/js.msg
+++ b/js/src/js.msg
@@ -232,6 +232,7 @@ MSG_DEF(JSMSG_CURLY_IN_COMPOUND,       0, JSEXN_SYNTAXERR, "missing } in compoun
 MSG_DEF(JSMSG_DECLARATION_AFTER_EXPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'export' keyword")
 MSG_DEF(JSMSG_DECLARATION_AFTER_IMPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'import' keyword")
 MSG_DEF(JSMSG_DEPRECATED_DELETE_OPERAND, 0, JSEXN_SYNTAXERR, "applying the 'delete' operator to an unqualified name is deprecated")
+MSG_DEF(JSMSG_DEPRECATED_FLAGS_ARG,    0, JSEXN_NONE, "flags argument of String.prototype.{search,match,replace} is deprecated")
 MSG_DEF(JSMSG_DEPRECATED_LET_BLOCK,      0, JSEXN_NONE, "JavaScript 1.7's let blocks are deprecated")
 MSG_DEF(JSMSG_DEPRECATED_FOR_EACH,     0, JSEXN_NONE, "JavaScript 1.6's for-each-in loops are deprecated; consider using ES6 for-of instead")
 MSG_DEF(JSMSG_DEPRECATED_LET_EXPRESSION, 0, JSEXN_NONE, "JavaScript 1.7's let expressions are deprecated")
diff --git a/js/src/jscompartment.cpp b/js/src/jscompartment.cpp
index cb9e3bf7a87d..1b9f3e75f457 100644
--- a/js/src/jscompartment.cpp
+++ b/js/src/jscompartment.cpp
@@ -46,6 +46,7 @@ JSCompartment::JSCompartment(Zone *zone, const JS::CompartmentOptions &options =
     isSelfHosting(false),
     marked(true),
     warnedAboutNoSuchMethod(false),
+    warnedAboutFlagsArgument(false),
     addonId(options.addonIdOrNull()),
 #ifdef DEBUG
     firedOnNewGlobalObject(false),
diff --git a/js/src/jscompartment.h b/js/src/jscompartment.h
index 5d54486eb19b..27f9a3170136 100644
--- a/js/src/jscompartment.h
+++ b/js/src/jscompartment.h
@@ -149,6 +149,7 @@ struct JSCompartment
     bool                         isSelfHosting;
     bool                         marked;
     bool                         warnedAboutNoSuchMethod;
+    bool                         warnedAboutFlagsArgument;
 
     // A null add-on ID means that the compartment is not associated with an
     // add-on.
diff --git a/js/src/jsstr.cpp b/js/src/jsstr.cpp
index 3b105088b62a..05af5d54298e 100644
--- a/js/src/jsstr.cpp
+++ b/js/src/jsstr.cpp
@@ -2137,6 +2137,13 @@ class MOZ_STACK_CLASS StringRegExpGuard
                 cx->compartment()->addTelemetry(filename, JSCompartment::DeprecatedFlagsArgument);
             }
 
+            if (!cx->compartment()->warnedAboutFlagsArgument) {
+                if (!JS_ReportErrorFlagsAndNumber(cx, JSREPORT_WARNING, GetErrorMessage, nullptr,
+                                                  JSMSG_DEPRECATED_FLAGS_ARG))
+                    return false;
+                cx->compartment()->warnedAboutFlagsArgument = true;
+            }
+
             opt = ToString<CanGC>(cx, args[optarg]);
             if (!opt)
                 return false;
diff --git a/js/src/tests/js1_5/String/replace-flags.js b/js/src/tests/js1_5/String/replace-flags.js
new file mode 100644
index 000000000000..656d4acfa6f6
--- /dev/null
+++ b/js/src/tests/js1_5/String/replace-flags.js
@@ -0,0 +1,15 @@
+// |reftest| skip-if(!xulRuntime.shell)
+
+var BUGNUMBER = 1142351;
+var summary = 'Add console warnings for non-standard flag argument of String.prototype.{search,match,replace}.';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+options("werror");
+assertEq(evaluate("'aaaA'.match('a', 'i')", {catchTermination: true}), "terminated");
+assertEq(evaluate("'aaaA'.search('a', 'i')", {catchTermination: true}), "terminated");
+assertEq(evaluate("'aaaA'.replace('a', 'b', 'g')", {catchTermination: true}), "terminated");
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/vm/Xdr.h b/js/src/vm/Xdr.h
index bcdbdc0f9c32..fa9e92ed8e23 100644
--- a/js/src/vm/Xdr.h
+++ b/js/src/vm/Xdr.h
@@ -29,11 +29,11 @@ namespace js {
  *
  *  https://developer.mozilla.org/en-US/docs/SpiderMonkey/Internals/Bytecode
  */
-static const uint32_t XDR_BYTECODE_VERSION_SUBTRAHEND = 267;
+static const uint32_t XDR_BYTECODE_VERSION_SUBTRAHEND = 268;
 static const uint32_t XDR_BYTECODE_VERSION =
     uint32_t(0xb973c0de - XDR_BYTECODE_VERSION_SUBTRAHEND);
 
-static_assert(JSErr_Limit == 388,
+static_assert(JSErr_Limit == 389,
               "GREETINGS, POTENTIAL SUBTRAHEND INCREMENTER! If you added or "
               "removed MSG_DEFs from js.msg, you should increment "
               "XDR_BYTECODE_VERSION_SUBTRAHEND and update this assertion's "