--- a/js/src/jit/VMFunctions.h
+++ b/js/src/jit/VMFunctions.h
@@ -776,23 +776,16 @@ template <>
 struct OutParamToRootType<MutableHandleObject> {
   static const VMFunction::RootType result = VMFunction::RootObject;
 };
 template <>
 struct OutParamToRootType<MutableHandleString> {
   static const VMFunction::RootType result = VMFunction::RootString;
 };
 
-template <class>
-struct MatchContext {};
-template <>
-struct MatchContext<JSContext*> {
-  static const bool valid = true;
-};
-
 // Extract the last element of a list of types.
 template <typename... ArgTypes>
 struct LastArg;
 
 template <>
 struct LastArg<> {
   typedef void Type;
   static constexpr size_t nbArgs = 0;
@@ -839,19 +832,19 @@ struct BitMask<Each, ResultType, Shift, 
 };
 
 // Extract VMFunction properties based on the signature of the function. The
 // properties are used to generate the logic for calling the VM function, and
 // also for marking the stack during GCs.
 template <typename... Args>
 struct FunctionInfo;
 
-template <class R, class Context, typename... Args>
-struct FunctionInfo<R (*)(Context, Args...)> : public VMFunction {
-  typedef R (*pf)(Context, Args...);
+template <class R, typename... Args>
+struct FunctionInfo<R (*)(JSContext*, Args...)> : public VMFunction {
+  using pf = R (*)(JSContext*, Args...);
 
   static DataType returnType() { return TypeToDataType<R>::result; }
   static DataType outParam() {
     return OutParamToDataType<typename LastArg<Args...>::Type>::result;
   }
   static RootType outParamRootType() {
     return OutParamToRootType<typename LastArg<Args...>::Type>::result;
   }
@@ -869,27 +862,23 @@ struct FunctionInfo<R (*)(Context, Args.
     return BitMask<TypeToRootType, uint64_t, 3, Args...>::result;
   }
   explicit FunctionInfo(pf fun, const char* name,
                         PopValues extraValuesToPop = PopValues(0))
       : VMFunction(JS_FUNC_TO_DATA_PTR(void*, fun), name, explicitArgs(),
                    argumentProperties(), argumentPassedInFloatRegs(),
                    argumentRootTypes(), outParam(), outParamRootType(),
                    returnType(), extraValuesToPop.numValues, NonTailCall) {
-    static_assert(MatchContext<Context>::valid,
-                  "Invalid cx type in VMFunction");
   }
   explicit FunctionInfo(pf fun, const char* name, MaybeTailCall expectTailCall,
                         PopValues extraValuesToPop = PopValues(0))
       : VMFunction(JS_FUNC_TO_DATA_PTR(void*, fun), name, explicitArgs(),
                    argumentProperties(), argumentPassedInFloatRegs(),
                    argumentRootTypes(), outParam(), outParamRootType(),
                    returnType(), extraValuesToPop.numValues, expectTailCall) {
-    static_assert(MatchContext<Context>::valid,
-                  "Invalid cx type in VMFunction");
   }
 };
 
 class AutoDetectInvalidation {
   JSContext* cx_;
   IonScript* ionScript_;
   MutableHandleValue rval_;
   bool disabled_;