Bug 1215744 - Unnamed class expressions shouldn't get a name property. (r=arai)

js/src/jsfun.cpp

@@ -487,6 +487,18 @@ fun_resolve(JSContext* cx, HandleObject obj, HandleId id, bool* resolvedp)
             if (fun->hasResolvedName())
                 return true;
 
+            if (fun->isClassConstructor()) {
+                // It's impossible to have an empty named class expression. We
+                // use empty as a sentinel when creating default class
+                // constructors.
+                MOZ_ASSERT(fun->atom() != cx->names().empty);
+
+                // Unnamed class expressions should not get a .name property
+                // at all.
+                if (fun->atom() == nullptr)
+                    return true;
+            }
+
             v.setString(fun->atom() == nullptr ? cx->runtime()->emptyString : fun->atom());
         }
 

js/src/jsfun.h

@@ -78,6 +78,7 @@ class JSFunction : public js::NativeObject
         /* Derived Flags values for convenience: */
         NATIVE_FUN = 0,
         NATIVE_CTOR = NATIVE_FUN | CONSTRUCTOR,
+        NATIVE_CLASS_CTOR = NATIVE_FUN | CONSTRUCTOR | CLASSCONSTRUCTOR_KIND,
         ASMJS_CTOR = ASMJS_KIND | NATIVE_CTOR,
         ASMJS_LAMBDA_CTOR = ASMJS_KIND | NATIVE_CTOR | LAMBDA,
         INTERPRETED_METHOD = INTERPRETED | METHOD_KIND,

js/src/tests/ecma_6/Class/className.js

@@ -173,10 +173,15 @@ testName(ExtendedExpr3, "base", false, false, false);
 
 // ---- anonymous ----
 
+// Anonymous class expressions don't get name properties unless specified in a
+// static manner.
 let Anon = class {
     constructor() {}
 };
-testName(Anon, "", true, false, false);
+testName(Anon, "", false, false, false);
+
+let AnonDefault = class { };
+testName(AnonDefault, "", false, false, false);
 
 let AnonWithGetter = class {
     constructor() {}
@@ -201,10 +206,11 @@ testName(AnonWithGetterSetter, "base", false, true, true);
 let ExtendedAnon1 = class extends Anon {
     constructor() {}
 };
-testName(ExtendedAnon1, "", true, false, false);
-delete ExtendedAnon1.name;
 testName(ExtendedAnon1, "", false, false, false);
 
+let ExtendedAnonDefault = class extends Anon { };
+testName(ExtendedAnonDefault, "", false, false, false);
+
 let ExtendedAnon2 = class extends AnonWithGetterSetter {
     constructor() {}
     static get name() { return "extend"; }

js/src/tests/ecma_6/Class/defaultConstructorExpr.js

@@ -1,11 +0,0 @@
-var test = `
-
-assertEq(class { }.name, "");
-
-`;
-
-if (classesEnabled())
-    eval(test);
-
-if (typeof reportCompare === 'function')
-    reportCompare(0,0,"OK");

js/src/vm/Interpreter.cpp

@@ -325,9 +325,9 @@ MakeDefaultConstructor(JSContext* cx, JSOp op, JSAtom* atom, HandleObject proto)
     bool derived = op == JSOP_DERIVEDCONSTRUCTOR;
     MOZ_ASSERT(derived == !!proto);
 
-    RootedAtom name(cx, atom);
+    RootedAtom name(cx, atom == cx->names().empty ? nullptr : atom);
     JSNative native = derived ? DefaultDerivedClassConstructor : DefaultClassConstructor;
-    return NewFunctionWithProto(cx, native, 0, JSFunction::NATIVE_CTOR, nullptr, name, proto);
+    return NewFunctionWithProto(cx, native, 0, JSFunction::NATIVE_CLASS_CTOR, nullptr, name, proto);
 }
 
 bool