--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -3633,17 +3633,18 @@ class JS_FRIEND_API(ReadOnlyCompileOptio
   protected:
     ReadOnlyCompileOptions()
       : TransitiveCompileOptions(),
         lineno(1),
         column(0),
         scriptSourceOffset(0),
         isRunOnce(false),
         nonSyntacticScope(false),
-        noScriptRval(false)
+        noScriptRval(false),
+        allowSyntaxParser(true)
     { }
 
     // Set all POD options (those not requiring reference counts, copies,
     // rooting, or other hand-holding) to their values in |rhs|.
     void copyPODOptions(const ReadOnlyCompileOptions& rhs);
 
   public:
     // Read-only accessors for non-POD options. The proper way to set these
@@ -3670,16 +3671,17 @@ class JS_FRIEND_API(ReadOnlyCompileOptio
     // starting and ending offsets within the full text. This
     // scriptSourceOffset field lets the frontend convert between these
     // offsets and offsets within the substring presented for compilation.
     unsigned scriptSourceOffset;
     // isRunOnce only applies to non-function scripts.
     bool isRunOnce;
     bool nonSyntacticScope;
     bool noScriptRval;
+    bool allowSyntaxParser;
 
   private:
     void operator=(const ReadOnlyCompileOptions&) = delete;
 };
 
 /**
  * Compilation options, with dynamic lifetime. An instance of this type
  * makes a copy of / holds / roots all dynamically allocated resources
@@ -3737,16 +3739,17 @@ class JS_FRIEND_API(OwningCompileOptions
     }
     OwningCompileOptions& setUTF8(bool u) { utf8 = u; return *this; }
     OwningCompileOptions& setColumn(unsigned c) { column = c; return *this; }
     OwningCompileOptions& setScriptSourceOffset(unsigned o) { scriptSourceOffset = o; return *this; }
     OwningCompileOptions& setIsRunOnce(bool once) { isRunOnce = once; return *this; }
     OwningCompileOptions& setNoScriptRval(bool nsr) { noScriptRval = nsr; return *this; }
     OwningCompileOptions& setSelfHostingMode(bool shm) { selfHostingMode = shm; return *this; }
     OwningCompileOptions& setCanLazilyParse(bool clp) { canLazilyParse = clp; return *this; }
+    OwningCompileOptions& setAllowSyntaxParser(bool clp) { allowSyntaxParser = clp; return *this; }
     OwningCompileOptions& setSourceIsLazy(bool l) { sourceIsLazy = l; return *this; }
     OwningCompileOptions& setNonSyntacticScope(bool n) { nonSyntacticScope = n; return *this; }
     OwningCompileOptions& setIntroductionType(const char* t) { introductionType = t; return *this; }
     bool setIntroductionInfo(JSContext* cx, const char* introducerFn, const char* intro,
                              unsigned line, JSScript* script, uint32_t offset)
     {
         if (!setIntroducerFilename(cx, introducerFn))
             return false;
@@ -3830,16 +3833,17 @@ class MOZ_STACK_CLASS JS_FRIEND_API(Comp
     }
     CompileOptions& setUTF8(bool u) { utf8 = u; return *this; }
     CompileOptions& setColumn(unsigned c) { column = c; return *this; }
     CompileOptions& setScriptSourceOffset(unsigned o) { scriptSourceOffset = o; return *this; }
     CompileOptions& setIsRunOnce(bool once) { isRunOnce = once; return *this; }
     CompileOptions& setNoScriptRval(bool nsr) { noScriptRval = nsr; return *this; }
     CompileOptions& setSelfHostingMode(bool shm) { selfHostingMode = shm; return *this; }
     CompileOptions& setCanLazilyParse(bool clp) { canLazilyParse = clp; return *this; }
+    CompileOptions& setAllowSyntaxParser(bool clp) { allowSyntaxParser = clp; return *this; }
     CompileOptions& setSourceIsLazy(bool l) { sourceIsLazy = l; return *this; }
     CompileOptions& setNonSyntacticScope(bool n) { nonSyntacticScope = n; return *this; }
     CompileOptions& setIntroductionType(const char* t) { introductionType = t; return *this; }
     CompileOptions& setIntroductionInfo(const char* introducerFn, const char* intro,
                                         unsigned line, JSScript* script, uint32_t offset)
     {
         introducerFilename_ = introducerFn;
         introductionType = intro;

--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -4404,30 +4404,54 @@ Parse(JSContext* cx, unsigned argc, Valu
         return false;
     }
     if (!args[0].isString()) {
         const char* typeName = InformalValueTypeName(args[0]);
         JS_ReportErrorASCII(cx, "expected string to parse, got %s", typeName);
         return false;
     }
 
+    bool allowSyntaxParser = true;
+
+    if (args.length() >= 2) {
+        if (!args[1].isObject()) {
+            const char* typeName = InformalValueTypeName(args[1]);
+            JS_ReportErrorASCII(cx, "expected object (options) to parse, got %s", typeName);
+            return false;
+        }
+        RootedObject objOptions(cx, &args[1].toObject());
+
+        RootedValue optionAllowSyntaxParser(cx);
+        if (!JS_GetProperty(cx, objOptions, "allowSyntaxParser", &optionAllowSyntaxParser))
+            return false;
+
+        if (optionAllowSyntaxParser.isBoolean()) {
+            allowSyntaxParser = optionAllowSyntaxParser.toBoolean();
+        } else if (!optionAllowSyntaxParser.isUndefined()) {
+            const char* typeName = InformalValueTypeName(optionAllowSyntaxParser);
+            JS_ReportErrorASCII(cx, "option `allowSyntaxParser` should be a boolean, got %s", typeName);
+            return false;
+        }
+    }
+
     JSFlatString* scriptContents = args[0].toString()->ensureFlat(cx);
     if (!scriptContents)
         return false;
 
     AutoStableStringChars stableChars(cx);
     if (!stableChars.initTwoByte(cx, scriptContents))
         return false;
 
     size_t length = scriptContents->length();
     const char16_t* chars = stableChars.twoByteRange().begin().get();
 
     CompileOptions options(cx);
     options.setIntroductionType("js shell parse")
-           .setFileAndLine("<string>", 1);
+           .setFileAndLine("<string>", 1)
+           .setAllowSyntaxParser(allowSyntaxParser);
 
     UsedNameTracker usedNames(cx);
     if (!usedNames.init())
         return false;
     Parser<FullParseHandler, char16_t> parser(cx, cx->tempLifoAlloc(), options, chars, length,
                                               /* foldConstants = */ false, usedNames, nullptr,
                                               nullptr);
     if (!parser.checkOptions())