diff --git a/src/ecmascript/spidermonkey-shared.c b/src/ecmascript/spidermonkey-shared.c
index 115587d07..a2bb7447c 100644
--- a/src/ecmascript/spidermonkey-shared.c
+++ b/src/ecmascript/spidermonkey-shared.c
@@ -91,7 +91,7 @@ spidermonkey_DefineFunctions(JSContext *cx, JSObject *obj,
  * @relates spidermonkeyFunctionSpec */
 JSObject *
 spidermonkey_InitClass(JSContext *cx, JSObject *obj,
-		       JSObject *parent_proto, JSClass *clasp,
+		       JSObject *parent_proto, const JSClass *clasp,
 		       JSNative constructor, unsigned int nargs,
 		       JSPropertySpec *ps,
 		       const spidermonkeyFunctionSpec *fs,
diff --git a/src/ecmascript/spidermonkey-shared.h b/src/ecmascript/spidermonkey-shared.h
index 10aa9fd18..87c758076 100644
--- a/src/ecmascript/spidermonkey-shared.h
+++ b/src/ecmascript/spidermonkey-shared.h
@@ -30,7 +30,7 @@ typedef struct spidermonkeyFunctionSpec {
 bool spidermonkey_DefineFunctions(JSContext *cx, JSObject *obj,
 				    const spidermonkeyFunctionSpec *fs);
 JSObject *spidermonkey_InitClass(JSContext *cx, JSObject *obj,
-				 JSObject *parent_proto, JSClass *clasp,
+				 JSObject *parent_proto, const JSClass *clasp,
 				 JSNative constructor, unsigned int nargs,
 				 JSPropertySpec *ps,
 				 const spidermonkeyFunctionSpec *fs,
diff --git a/src/ecmascript/spidermonkey.c b/src/ecmascript/spidermonkey.c
index 912b8f399..5d1778809 100644
--- a/src/ecmascript/spidermonkey.c
+++ b/src/ecmascript/spidermonkey.c
@@ -80,7 +80,7 @@ error_reporter(JSContext *ctx, JSErrorReport *report)
 	if (!comp) {
 		return;
 	}
-	struct ecmascript_interpreter *interpreter = JS::GetRealmPrivate(comp);
+	struct ecmascript_interpreter *interpreter = (struct ecmascript_interpreter *)JS::GetRealmPrivate(comp);
 	struct session *ses = interpreter->vs->doc_view->session;
 	struct terminal *term;
 	struct string msg;
@@ -143,8 +143,6 @@ spidermonkey_get_interpreter(struct ecmascript_interpreter *interpreter)
 	JSObject *console_obj, *document_obj, /* *forms_obj,*/ *history_obj, *location_obj,
 	         *statusbar_obj, *menubar_obj, *navigator_obj, *localstorage_obj, *screen_obj;
 
-	static int initialized = 0;
-
 	assert(interpreter);
 	if (!js_module_init_ok) return NULL;
 
@@ -244,7 +242,7 @@ spidermonkey_get_interpreter(struct ecmascript_interpreter *interpreter)
 	if (!menubar_obj) {
 		goto release_and_fail;
 	}
-	JS_SetPrivate(menubar_obj, "t"); /* to @menubar_class */
+	JS_SetPrivate(menubar_obj, (char *)"t"); /* to @menubar_class */
 
 	statusbar_obj = JS_InitClass(ctx, window_obj, nullptr,
 				     &statusbar_class, NULL, 0,
@@ -253,7 +251,7 @@ spidermonkey_get_interpreter(struct ecmascript_interpreter *interpreter)
 	if (!statusbar_obj) {
 		goto release_and_fail;
 	}
-	JS_SetPrivate(statusbar_obj, "s"); /* to @statusbar_class */
+	JS_SetPrivate(statusbar_obj, (char *)"s"); /* to @statusbar_class */
 
 	navigator_obj = JS_InitClass(ctx, window_obj, nullptr,
 				     &navigator_class, NULL, 0,
@@ -293,12 +291,9 @@ release_and_fail:
 void
 spidermonkey_put_interpreter(struct ecmascript_interpreter *interpreter)
 {
-	JSContext *ctx;
-
 	assert(interpreter);
 	if (!js_module_init_ok) return;
 
-	ctx = interpreter->backend_data;
 	if (interpreter->ac2) {
 		delete (JSAutoRealm *)interpreter->ac2;
 	}
@@ -353,8 +348,8 @@ spidermonkey_eval(struct ecmascript_interpreter *interpreter,
 	if (!js_module_init_ok) {
 		return;
 	}
-	ctx = interpreter->backend_data;
-	JS::Realm *comp = JS::EnterRealm(ctx, interpreter->ac);
+	ctx = (JSContext *)interpreter->backend_data;
+	JS::Realm *comp = JS::EnterRealm(ctx, (JSObject *)interpreter->ac);
 
 	interpreter->heartbeat = add_heartbeat(interpreter);
 	interpreter->ret = ret;
@@ -386,8 +381,8 @@ spidermonkey_call_function(struct ecmascript_interpreter *interpreter,
 	if (!js_module_init_ok) {
 		return;
 	}
-	ctx = interpreter->backend_data;
-	JS::Realm *comp = JS::EnterRealm(ctx, interpreter->ac);
+	ctx = (JSContext *)interpreter->backend_data;
+	JS::Realm *comp = JS::EnterRealm(ctx, (JSObject *)interpreter->ac);
 
 	interpreter->heartbeat = add_heartbeat(interpreter);
 	interpreter->ret = ret;
@@ -411,11 +406,11 @@ spidermonkey_eval_stringback(struct ecmascript_interpreter *interpreter,
 
 	assert(interpreter);
 	if (!js_module_init_ok) return NULL;
-	ctx = interpreter->backend_data;
+	ctx = (JSContext *)interpreter->backend_data;
 	interpreter->ret = NULL;
 	interpreter->heartbeat = add_heartbeat(interpreter);
 
-	JS::Realm *comp = JS::EnterRealm(ctx, interpreter->ac);
+	JS::Realm *comp = JS::EnterRealm(ctx, (JSObject *)interpreter->ac);
 
 	JS::RootedObject cg(ctx, JS::CurrentGlobalOrNull(ctx));
 	JS::RootedValue r_rval(ctx, rval);
@@ -458,10 +453,10 @@ spidermonkey_eval_boolback(struct ecmascript_interpreter *interpreter,
 
 	assert(interpreter);
 	if (!js_module_init_ok) return 0;
-	ctx = interpreter->backend_data;
+	ctx = (JSContext *)interpreter->backend_data;
 	interpreter->ret = NULL;
 
-	JS::Realm *comp = JS::EnterRealm(ctx, interpreter->ac);
+	JS::Realm *comp = JS::EnterRealm(ctx, (JSObject *)interpreter->ac);
 
 	JS::CompileOptions options(ctx);
 	JS::RootedObjectVector ag(ctx);