Reland: change most cases of variable redeclaration from TypeError to SyntaxError.

src/runtime/runtime-scopes.cc

Index: src/runtime/runtime-scopes.cc
diff --git a/src/runtime/runtime-scopes.cc b/src/runtime/runtime-scopes.cc
index 5ba0f5871abfabac7d7027c4ba3ff4df9b9dc65a..0bdbe2e44172da6f9a0efd3bac703ba0aafc8a5e 100644
--- a/src/runtime/runtime-scopes.cc
+++ b/src/runtime/runtime-scopes.cc
@@ -16,10 +16,18 @@
 namespace v8 {
 namespace internal {
 
-static Object* ThrowRedeclarationError(Isolate* isolate, Handle<String> name) {
+enum class RedeclarationType { kSyntaxError = 0, kTypeError = 1 };
+
+static Object* ThrowRedeclarationError(Isolate* isolate, Handle<String> name,
+                                       RedeclarationType redeclaration_type) {
   HandleScope scope(isolate);
-  THROW_NEW_ERROR_RETURN_FAILURE(
-      isolate, NewTypeError(MessageTemplate::kVarRedeclaration, name));
+  if (redeclaration_type == RedeclarationType::kSyntaxError) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewSyntaxError(MessageTemplate::kVarRedeclaration, name));
+  } else {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewTypeError(MessageTemplate::kVarRedeclaration, name));
+  }
 }
 
 
@@ -34,13 +42,18 @@ RUNTIME_FUNCTION(Runtime_ThrowConstAssignError) {
 static Object* DeclareGlobals(Isolate* isolate, Handle<JSGlobalObject> global,
                               Handle<String> name, Handle<Object> value,
                               PropertyAttributes attr, bool is_var,
-                              bool is_function) {
+                              bool is_function,
+                              RedeclarationType redeclaration_type) {
   Handle<ScriptContextTable> script_contexts(
       global->native_context()->script_context_table());
   ScriptContextTable::LookupResult lookup;
   if (ScriptContextTable::Lookup(script_contexts, name, &lookup) &&
       IsLexicalVariableMode(lookup.mode)) {
-    return ThrowRedeclarationError(isolate, name);
+    // ES#sec-globaldeclarationinstantiation 6.a:
+    // If envRec.HasLexicalDeclaration(name) is true, throw a SyntaxError
+    // exception.
+    return ThrowRedeclarationError(isolate, name,
+                                   RedeclarationType::kSyntaxError);
   }
 
   // Do the lookup own properties only, see ES5 erratum.
@@ -67,7 +80,11 @@ static Object* DeclareGlobals(Isolate* isolate, Handle<JSGlobalObject> global,
       if (old_details.IsReadOnly() || old_details.IsDontEnum() ||
           (it.state() == LookupIterator::ACCESSOR &&
            it.GetAccessors()->IsAccessorPair())) {
-        return ThrowRedeclarationError(isolate, name);
+        // ES#sec-globaldeclarationinstantiation 5.d:
+        // If hasRestrictedGlobal is true, throw a SyntaxError exception.
+        // ES#sec-evaldeclarationinstantiation 8.a.iv.1.b:
+        // If fnDefinable is false, throw a TypeError exception.
+        return ThrowRedeclarationError(isolate, name, redeclaration_type);
       }
       // If the existing property is not configurable, keep its attributes. Do
       attr = old_attributes;
@@ -130,9 +147,11 @@ RUNTIME_FUNCTION(Runtime_DeclareGlobals) {
     if (is_function && is_native) attr |= READ_ONLY;
     if (!is_eval) attr |= DONT_DELETE;
 
-    Object* result = DeclareGlobals(isolate, global, name, value,
-                                    static_cast<PropertyAttributes>(attr),
-                                    is_var, is_function);
+    // ES#sec-globaldeclarationinstantiation 5.d:
+    // If hasRestrictedGlobal is true, throw a SyntaxError exception.
+    Object* result = DeclareGlobals(
+        isolate, global, name, value, static_cast<PropertyAttributes>(attr),
+        is_var, is_function, RedeclarationType::kSyntaxError);
     if (isolate->has_pending_exception()) return result;
   });
 
@@ -214,7 +233,13 @@ Object* DeclareEvalHelper(Isolate* isolate, Handle<String> name,
   // Check for a conflict with a lexically scoped variable
   context_arg->Lookup(name, LEXICAL_TEST, &index, &attributes, &binding_flags);
   if (attributes != ABSENT && binding_flags == BINDING_CHECK_INITIALIZED) {
-    return ThrowRedeclarationError(isolate, name);
+    // ES#sec-evaldeclarationinstantiation 5.a.i.1:
+    // If varEnvRec.HasLexicalDeclaration(name) is true, throw a SyntaxError
+    // exception.
+    // ES#sec-evaldeclarationinstantiation 5.d.ii.2.a.i:
+    // Throw a SyntaxError exception.
+    return ThrowRedeclarationError(isolate, name,
+                                   RedeclarationType::kSyntaxError);
   }
 
   Handle<Object> holder = context->Lookup(name, DONT_FOLLOW_CHAINS, &index,
@@ -224,20 +249,23 @@ Object* DeclareEvalHelper(Isolate* isolate, Handle<String> name,
   Handle<JSObject> object;
 
   if (attributes != ABSENT && holder->IsJSGlobalObject()) {
+    // ES#sec-evaldeclarationinstantiation 8.a.iv.1.b:
+    // If fnDefinable is false, throw a TypeError exception.
     return DeclareGlobals(isolate, Handle<JSGlobalObject>::cast(holder), name,
-                          value, NONE, is_var, is_function);
+                          value, NONE, is_var, is_function,
+                          RedeclarationType::kTypeError);
   }
   if (context_arg->extension()->IsJSGlobalObject()) {
     Handle<JSGlobalObject> global(
         JSGlobalObject::cast(context_arg->extension()), isolate);
     return DeclareGlobals(isolate, global, name, value, NONE, is_var,
-                          is_function);
+                          is_function, RedeclarationType::kTypeError);
   } else if (context->IsScriptContext()) {
     DCHECK(context->global_object()->IsJSGlobalObject());
     Handle<JSGlobalObject> global(
         JSGlobalObject::cast(context->global_object()), isolate);
     return DeclareGlobals(isolate, global, name, value, NONE, is_var,
-                          is_function);
+                          is_function, RedeclarationType::kTypeError);
   }
 
   if (attributes != ABSENT) {
@@ -581,7 +609,11 @@ static Object* FindNameClash(Handle<ScopeInfo> scope_info,
     ScriptContextTable::LookupResult lookup;
     if (ScriptContextTable::Lookup(script_context, name, &lookup)) {
       if (IsLexicalVariableMode(mode) || IsLexicalVariableMode(lookup.mode)) {
-        return ThrowRedeclarationError(isolate, name);
+        // ES#sec-globaldeclarationinstantiation 5.b:
+        // If envRec.HasLexicalDeclaration(name) is true, throw a SyntaxError
+        // exception.
+        return ThrowRedeclarationError(isolate, name,
+                                       RedeclarationType::kSyntaxError);
       }
     }
 
@@ -591,7 +623,13 @@ static Object* FindNameClash(Handle<ScopeInfo> scope_info,
       Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
       if (!maybe.IsJust()) return isolate->heap()->exception();
       if ((maybe.FromJust() & DONT_DELETE) != 0) {
-        return ThrowRedeclarationError(isolate, name);
+        // ES#sec-globaldeclarationinstantiation 5.a:
+        // If envRec.HasVarDeclaration(name) is true, throw a SyntaxError
+        // exception.
+        // ES#sec-globaldeclarationinstantiation 5.d:
+        // If hasRestrictedGlobal is true, throw a SyntaxError exception.
+        return ThrowRedeclarationError(isolate, name,
+                                       RedeclarationType::kSyntaxError);
       }
 
       JSGlobalObject::InvalidatePropertyCell(global_object, name);