Allow var/function declarations to shadow built-in globals in script mode

source/units/Goccia.Builtins.Benchmark.pas

@@ -185,9 +185,9 @@ constructor TGocciaBenchmark.Create(const AName: string; const AScope: TGocciaSc
   FRegisteredBenchmarks := TObjectList<TBenchmarkCase>.Create;
   FCurrentSuiteName := '';
 
-  AScope.DefineLexicalBinding('suite', TGocciaNativeFunctionValue.Create(Suite, 'suite', 2), dtConst);
-  AScope.DefineLexicalBinding('bench', TGocciaNativeFunctionValue.Create(Bench, 'bench', 2), dtConst);
-  AScope.DefineLexicalBinding('runBenchmarks', TGocciaNativeFunctionValue.Create(RunBenchmarks, 'runBenchmarks', 0), dtConst);
+  AScope.DefineLexicalBinding('suite', TGocciaNativeFunctionValue.Create(Suite, 'suite', 2), dtConst, True);
+  AScope.DefineLexicalBinding('bench', TGocciaNativeFunctionValue.Create(Bench, 'bench', 2), dtConst, True);
+  AScope.DefineLexicalBinding('runBenchmarks', TGocciaNativeFunctionValue.Create(RunBenchmarks, 'runBenchmarks', 0), dtConst, True);
 end;
 
 destructor TGocciaBenchmark.Destroy;

source/units/Goccia.Builtins.CSV.pas

@@ -81,7 +81,7 @@ constructor TGocciaCSVBuiltin.Create(const AName: string;
   end;
 
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaCSVBuiltin.Destroy;

source/units/Goccia.Builtins.Console.pas

@@ -118,7 +118,7 @@ constructor TGocciaConsole.Create(const AName: string; const AScope: TGocciaScop
   end;
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 procedure TGocciaConsole.EmitLine(const AMethod, ALine: string);

source/units/Goccia.Builtins.DisposableStack.pas

@@ -359,11 +359,11 @@ constructor TGocciaBuiltinDisposableStack.Create(const AName: string;
 
   DisposableStackFunc := TGocciaNativeFunctionValue.Create(
     DisposableStackConstructor, CONSTRUCTOR_DISPOSABLE_STACK, 0);
-  AScope.DefineLexicalBinding(CONSTRUCTOR_DISPOSABLE_STACK, DisposableStackFunc, dtConst);
+  AScope.DefineLexicalBinding(CONSTRUCTOR_DISPOSABLE_STACK, DisposableStackFunc, dtConst, True);
 
   AsyncDisposableStackFunc := TGocciaNativeFunctionValue.Create(
     AsyncDisposableStackConstructor, CONSTRUCTOR_ASYNC_DISPOSABLE_STACK, 0);
-  AScope.DefineLexicalBinding(CONSTRUCTOR_ASYNC_DISPOSABLE_STACK, AsyncDisposableStackFunc, dtConst);
+  AScope.DefineLexicalBinding(CONSTRUCTOR_ASYNC_DISPOSABLE_STACK, AsyncDisposableStackFunc, dtConst, True);
 end;
 
 function TGocciaBuiltinDisposableStack.DisposableStackConstructor(

source/units/Goccia.Builtins.GlobalBigInt.pas

@@ -98,7 +98,7 @@ constructor TGocciaGlobalBigInt.Create(const AName: string; const AScope: TGocci
     TGocciaPropertyDescriptorData.Create(Proto, []));
 
   // Bind BigInt in scope
-  AScope.DefineLexicalBinding(AName, FBigIntFunction, dtLet);
+  AScope.DefineLexicalBinding(AName, FBigIntFunction, dtLet, True);
 end;
 
 // ES2026 §21.2.1.1 BigInt(value) — conversion function

source/units/Goccia.Builtins.GlobalFFI.pas

@@ -67,7 +67,7 @@ constructor TGocciaGlobalFFI.Create(const AName: string; const AScope: TGocciaSc
   end;
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtConst);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtConst, True);
 end;
 
 function TGocciaGlobalFFI.FFIOpen(const AArgs: TGocciaArgumentsCollection; const AThisValue: TGocciaValue): TGocciaValue;

source/units/Goccia.Builtins.GlobalFetch.pas

@@ -107,7 +107,7 @@ constructor TGocciaGlobalFetch.Create(const AName: string;
 
   // Register fetch as a global function
   AScope.DefineLexicalBinding('fetch',
-    TGocciaNativeFunctionValue.Create(FetchCallback, 'fetch', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(FetchCallback, 'fetch', 1), dtConst, True);
 end;
 
 destructor TGocciaGlobalFetch.Destroy;

source/units/Goccia.Builtins.GlobalPromise.pas

@@ -478,7 +478,7 @@ constructor TGocciaGlobalPromise.Create(const AName: string; const AScope: TGocc
   end;
   RegisterMemberDefinitions(FPromiseConstructor, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FPromiseConstructor, dtLet);
+  AScope.DefineLexicalBinding(AName, FPromiseConstructor, dtLet, True);
 end;
 
 // ES2026 §27.2.4.8 get Promise [ @@species ]

source/units/Goccia.Builtins.GlobalProxy.pas

@@ -48,7 +48,7 @@ constructor TGocciaGlobalProxy.Create(const AScope: TGocciaScope);
       PROP_REVOCABLE, 2));
   FConstructorValue := ConstructorFn;
 
-  AScope.DefineLexicalBinding(CONSTRUCTOR_PROXY, FConstructorValue, dtConst);
+  AScope.DefineLexicalBinding(CONSTRUCTOR_PROXY, FConstructorValue, dtConst, True);
 end;
 
 // ES2026 §28.2.1 Proxy(target, handler)

source/units/Goccia.Builtins.GlobalReflect.pas

@@ -96,7 +96,7 @@ constructor TGocciaGlobalReflect.Create(const AName: string; const AScope: TGocc
   end;
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtConst);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtConst, True);
 end;
 
 // ES2026 §28.1.1 Reflect.apply(target, thisArgument, argumentsList)

source/units/Goccia.Builtins.GlobalRegExp.pas

@@ -350,7 +350,7 @@ constructor TGocciaGlobalRegExp.Create(const AName: string;
   end;
   RegisterMemberDefinitions(FRegExpConstructor, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FRegExpConstructor, dtConst);
+  AScope.DefineLexicalBinding(AName, FRegExpConstructor, dtConst, True);
 end;
 
 // ES2026 §22.2.4.2 get RegExp [ @@species ]

source/units/Goccia.Builtins.GlobalSymbol.pas

@@ -116,7 +116,7 @@ constructor TGocciaGlobalSymbol.Create(const AName: string; const AScope: TGocci
     TGocciaPropertyDescriptorData.Create(FSymbolFunction, [pfConfigurable, pfWritable]));
 
   // Bind Symbol in scope
-  AScope.DefineLexicalBinding(AName, FSymbolFunction, dtLet);
+  AScope.DefineLexicalBinding(AName, FSymbolFunction, dtLet, True);
 end;
 
 destructor TGocciaGlobalSymbol.Destroy;

source/units/Goccia.Builtins.Globals.pas

@@ -209,9 +209,9 @@ constructor TGocciaGlobals.Create(const AName: string; const AScope: TGocciaScop
 begin
   inherited Create(AName, AScope, AThrowError);
 
-  AScope.DefineLexicalBinding('undefined', TGocciaUndefinedLiteralValue.UndefinedValue, dtConst);
-  AScope.DefineLexicalBinding('NaN', TGocciaNumberLiteralValue.NaNValue, dtConst);
-  AScope.DefineLexicalBinding('Infinity', TGocciaNumberLiteralValue.InfinityValue, dtConst);
+  AScope.DefineLexicalBinding('undefined', TGocciaUndefinedLiteralValue.UndefinedValue, dtConst, True);
+  AScope.DefineLexicalBinding('NaN', TGocciaNumberLiteralValue.NaNValue, dtConst, True);
+  AScope.DefineLexicalBinding('Infinity', TGocciaNumberLiteralValue.InfinityValue, dtConst, True);
 
   FErrorProto := TGocciaObjectValue.Create;
   FErrorProto.DefineProperty(PROP_NAME, TGocciaPropertyDescriptorData.Create(TGocciaStringLiteralValue.Create(ERROR_NAME), [pfConfigurable, pfWritable]));
@@ -323,36 +323,36 @@ constructor TGocciaGlobals.Create(const AName: string; const AScope: TGocciaScop
   FSuppressedErrorProto.DefineProperty(PROP_CONSTRUCTOR, TGocciaPropertyDescriptorData.Create(SuppressedErrorConstructorFunc, [pfConfigurable, pfWritable]));
   FDOMExceptionProto.DefineProperty(PROP_CONSTRUCTOR, TGocciaPropertyDescriptorData.Create(DOMExceptionConstructorFunc, [pfConfigurable, pfWritable]));
 
-  AScope.DefineLexicalBinding(ERROR_NAME, ErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(TYPE_ERROR_NAME, TypeErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(REFERENCE_ERROR_NAME, ReferenceErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(RANGE_ERROR_NAME, RangeErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(SYNTAX_ERROR_NAME, SyntaxErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(URI_ERROR_NAME, URIErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(AGGREGATE_ERROR_NAME, AggregateErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(SUPPRESSED_ERROR_NAME, SuppressedErrorConstructorFunc, dtConst);
-  AScope.DefineLexicalBinding(DOM_EXCEPTION_NAME, DOMExceptionConstructorFunc, dtConst);
+  AScope.DefineLexicalBinding(ERROR_NAME, ErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(TYPE_ERROR_NAME, TypeErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(REFERENCE_ERROR_NAME, ReferenceErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(RANGE_ERROR_NAME, RangeErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(SYNTAX_ERROR_NAME, SyntaxErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(URI_ERROR_NAME, URIErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(AGGREGATE_ERROR_NAME, AggregateErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(SUPPRESSED_ERROR_NAME, SuppressedErrorConstructorFunc, dtConst, True);
+  AScope.DefineLexicalBinding(DOM_EXCEPTION_NAME, DOMExceptionConstructorFunc, dtConst, True);
 
   AScope.DefineLexicalBinding('encodeURI',
-    TGocciaNativeFunctionValue.Create(EncodeURICallback, 'encodeURI', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(EncodeURICallback, 'encodeURI', 1), dtConst, True);
 
   AScope.DefineLexicalBinding('decodeURI',
-    TGocciaNativeFunctionValue.Create(DecodeURICallback, 'decodeURI', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(DecodeURICallback, 'decodeURI', 1), dtConst, True);
 
   AScope.DefineLexicalBinding('encodeURIComponent',
-    TGocciaNativeFunctionValue.Create(EncodeURIComponentCallback, 'encodeURIComponent', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(EncodeURIComponentCallback, 'encodeURIComponent', 1), dtConst, True);
 
   AScope.DefineLexicalBinding('decodeURIComponent',
-    TGocciaNativeFunctionValue.Create(DecodeURIComponentCallback, 'decodeURIComponent', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(DecodeURIComponentCallback, 'decodeURIComponent', 1), dtConst, True);
 end;
 
 procedure TGocciaGlobals.RegisterRuntimeGlobals;
 begin
   FScope.DefineLexicalBinding('queueMicrotask',
-    TGocciaNativeFunctionValue.Create(QueueMicrotaskCallback, 'queueMicrotask', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(QueueMicrotaskCallback, 'queueMicrotask', 1), dtConst, True);
 
   FScope.DefineLexicalBinding('structuredClone',
-    TGocciaNativeFunctionValue.Create(StructuredCloneCallback, 'structuredClone', 1), dtConst);
+    TGocciaNativeFunctionValue.Create(StructuredCloneCallback, 'structuredClone', 1), dtConst, True);
 end;
 
 { NativeError ( message [ , options ] ) — §20.5.6.1.1 (shared by all NativeError constructors)

source/units/Goccia.Builtins.JSON.pas

@@ -92,7 +92,7 @@ constructor TGocciaJSONBuiltin.Create(const AName: string; const AScope: TGoccia
   end;
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaJSONBuiltin.Destroy;

source/units/Goccia.Builtins.JSON5.pas

@@ -130,7 +130,7 @@ constructor TGocciaJSON5Builtin.Create(const AName: string;
   end;
 
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaJSON5Builtin.Destroy;

source/units/Goccia.Builtins.JSONL.pas

@@ -75,7 +75,7 @@ constructor TGocciaJSONLBuiltin.Create(const AName: string;
   end;
 
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaJSONLBuiltin.Destroy;

source/units/Goccia.Builtins.Math.pas

@@ -151,7 +151,7 @@ constructor TGocciaMath.Create(const AName: string; const AScope: TGocciaScope;
   end;
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
 
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 // §21.3.2.1 Math.abs ( x )

source/units/Goccia.Builtins.Performance.pas

@@ -239,7 +239,7 @@ constructor TGocciaPerformance.Create(const AName: string; const AScope: TGoccia
     TGocciaObjectValue.InitializeSharedPrototype;
 
   FBuiltinObject := TGocciaPerformanceValue.Create;
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 initialization

source/units/Goccia.Builtins.TOML.pas

@@ -63,7 +63,7 @@ constructor TGocciaTOMLBuiltin.Create(const AName: string;
   end;
 
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaTOMLBuiltin.Destroy;

source/units/Goccia.Builtins.TSV.pas

@@ -81,7 +81,7 @@ constructor TGocciaTSVBuiltin.Create(const AName: string;
   end;
 
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaTSVBuiltin.Destroy;

source/units/Goccia.Builtins.Temporal.pas

@@ -140,7 +140,7 @@ constructor TGocciaTemporalBuiltin.Create(const AName: string; const AScope: TGo
       [pfConfigurable]);
     RegisterMemberDefinitions(FTemporalNamespace, TemporalMembers);
 
-    AScope.DefineLexicalBinding(AName, FTemporalNamespace, dtLet);
+    AScope.DefineLexicalBinding(AName, FTemporalNamespace, dtLet, True);
   finally
     TGarbageCollector.Instance.RemoveTempRoot(FTemporalNamespace);
   end;

source/units/Goccia.Builtins.TestingLibrary.pas

@@ -2384,7 +2384,7 @@ constructor TGocciaTestAssertions.Create(const AName: string; const AScope: TGoc
       GlobalObject.DefineProperty(AName,
         TGocciaPropertyDescriptorData.Create(AValue, [pfWritable, pfConfigurable]))
     else
-      AScope.DefineLexicalBinding(AName, AValue, dtConst);
+      AScope.DefineLexicalBinding(AName, AValue, dtConst, True);
   end;
 
 begin
@@ -2419,8 +2419,8 @@ constructor TGocciaTestAssertions.Create(const AName: string; const AScope: TGoc
   // Private aliases used by generated Test262 wrappers.  Some conformance
   // tests intentionally declare globals named describe/test.
   AScope.DefineLexicalBinding('__gocciaTest262Describe', DescribeFunction,
-    dtConst);
-  AScope.DefineLexicalBinding('__gocciaTest262Test', TestFunction, dtConst);
+    dtConst, True);
+  AScope.DefineLexicalBinding('__gocciaTest262Test', TestFunction, dtConst, True);
 
   ItFunction := TGocciaNativeFunctionValue.Create(It, 'it', 2);
   ConfigureTestFunction(ItFunction);

source/units/Goccia.Builtins.YAML.pas

@@ -66,7 +66,7 @@ constructor TGocciaYAMLBuiltin.Create(const AName: string;
   end;
 
   RegisterMemberDefinitions(FBuiltinObject, FStaticMembers);
-  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet);
+  AScope.DefineLexicalBinding(AName, FBuiltinObject, dtLet, True);
 end;
 
 destructor TGocciaYAMLBuiltin.Destroy;

source/units/Goccia.Engine.pas

@@ -587,7 +587,7 @@ procedure TGocciaEngine.ExecuteShims;
       LoadShimValue(FInterpreter, Shim)
     else
       FInterpreter.GlobalScope.DefineLexicalBinding(Shim.Name,
-        LoadShimValue(FInterpreter, Shim), dtConst);
+        LoadShimValue(FInterpreter, Shim), dtConst, True);
   end;
 end;
 
@@ -745,7 +745,7 @@ procedure TGocciaEngine.RegisterBuiltIns;
   FBuiltinGlobalString := TGocciaGlobalString.Create(CONSTRUCTOR_STRING, Scope, ThrowError);
   FBuiltinGlobals := TGocciaGlobals.Create('Globals', Scope, ThrowError);
   FBuiltinDisposableStack := TGocciaBuiltinDisposableStack.Create('DisposableStack', Scope, ThrowError);
-  Scope.DefineLexicalBinding(CONSTRUCTOR_ITERATOR, TGocciaIteratorValue.CreateGlobalObject, dtConst);
+  Scope.DefineLexicalBinding(CONSTRUCTOR_ITERATOR, TGocciaIteratorValue.CreateGlobalObject, dtConst, True);
   RegisterBuiltinConstructors;
 end;
 
@@ -892,12 +892,12 @@ procedure TGocciaEngine.RegisterBuiltinConstructors;
   if Assigned(FBuiltinArrayBuffer) then
     for Key in FBuiltinArrayBuffer.BuiltinObject.GetAllPropertyNames do
       ArrayBufferConstructor.SetProperty(Key, FBuiltinArrayBuffer.BuiltinObject.GetProperty(Key));
-  FInterpreter.GlobalScope.DefineLexicalBinding(CONSTRUCTOR_ARRAY_BUFFER, ArrayBufferConstructor, dtConst);
+  FInterpreter.GlobalScope.DefineLexicalBinding(CONSTRUCTOR_ARRAY_BUFFER, ArrayBufferConstructor, dtConst, True);
 
   SharedArrayBufferConstructor := TGocciaSharedArrayBufferClassValue.Create(CONSTRUCTOR_SHARED_ARRAY_BUFFER, nil);
   TGocciaSharedArrayBufferValue.ExposePrototype(SharedArrayBufferConstructor);
   SharedArrayBufferConstructor.Prototype.Prototype := ObjectConstructor.Prototype;
-  FInterpreter.GlobalScope.DefineLexicalBinding(CONSTRUCTOR_SHARED_ARRAY_BUFFER, SharedArrayBufferConstructor, dtConst);
+  FInterpreter.GlobalScope.DefineLexicalBinding(CONSTRUCTOR_SHARED_ARRAY_BUFFER, SharedArrayBufferConstructor, dtConst, True);
 
   // Create %TypedArray% intrinsic (not globally exposed per spec §23.2.1)
   FTypedArrayIntrinsic := TGocciaClassValue.Create('TypedArray', nil);
@@ -992,7 +992,7 @@ procedure TGocciaEngine.RegisterBuiltinConstructors;
   TGocciaClassValue.PatchDefaultPrototype(NumberConstructor);
   TGocciaClassValue.PatchDefaultPrototype(BooleanConstructor);
   TGocciaClassValue.PatchDefaultPrototype(FunctionConstructor);
-  FInterpreter.GlobalScope.DefineLexicalBinding('Function', FunctionConstructor, dtConst);
+  FInterpreter.GlobalScope.DefineLexicalBinding('Function', FunctionConstructor, dtConst, True);
 
   // ES2026 §20.4.3: Symbol.prototype's [[Prototype]] is %Object.prototype%
   if Assigned(TGocciaSymbolValue.SharedPrototype) then
@@ -1048,7 +1048,7 @@ procedure TGocciaEngine.RegisterTypedArrayConstructor(const AName: string; const
     TGocciaTypedArrayValue.SetUint8Prototype(TAConstructor.Prototype);
   end;
 
-  FInterpreter.GlobalScope.DefineLexicalBinding(AName, TAConstructor, dtConst);
+  FInterpreter.GlobalScope.DefineLexicalBinding(AName, TAConstructor, dtConst, True);
 end;
 
 procedure TGocciaEngine.RegisterGlobalThis;
@@ -1084,7 +1084,7 @@ procedure TGocciaEngine.RegisterGlobalThis;
   if Scope.ContainsOwnLexicalBinding('globalThis') then
     Scope.ForceUpdateBinding('globalThis', GlobalThisObj)
   else
-    Scope.DefineLexicalBinding('globalThis', GlobalThisObj, dtConst);
+    Scope.DefineLexicalBinding('globalThis', GlobalThisObj, dtConst, True);
 
   // ES2026 §9.1.2.5 NewGlobalEnvironment: a global Environment Record's
   // [[GlobalThisValue]] is the global object. Top-level `this` resolves
@@ -1150,7 +1150,7 @@ procedure TGocciaEngine.RegisterGocciaScriptGlobal;
   GocciaObj.AssignProperty('gc', GCFunc);
 
   FGocciaGlobal := GocciaObj;
-  FInterpreter.GlobalScope.DefineLexicalBinding('Goccia', FGocciaGlobal, dtConst);
+  FInterpreter.GlobalScope.DefineLexicalBinding('Goccia', FGocciaGlobal, dtConst, True);
 end;
 
 function TGocciaEngine.GetResolver: TGocciaModuleResolver;

source/units/Goccia.ObjectModel.Engine.pas

@@ -136,7 +136,7 @@ procedure RegisterTypeDefinition(const AScope: TGocciaScope;
           ASpeciesGetter, 'get [Symbol.species]', 0),
         nil, [pfConfigurable]));
 
-  AScope.DefineLexicalBinding(ATypeDefinition.ConstructorName, AConstructor, dtConst);
+  AScope.DefineLexicalBinding(ATypeDefinition.ConstructorName, AConstructor, dtConst, True);
 end;
 
 end.

source/units/Goccia.Runtime.pas

@@ -812,7 +812,7 @@ procedure TGocciaRuntimeExtension.RegisterRuntimeConstructors;
   begin
     PerformanceConstructor := TGocciaPerformance.CreateInterfaceObject;
     FEngine.Interpreter.GlobalScope.DefineLexicalBinding(
-      CONSTRUCTOR_PERFORMANCE, PerformanceConstructor, dtConst);
+      CONSTRUCTOR_PERFORMANCE, PerformanceConstructor, dtConst, True);
   end;
 end;
 

source/units/Goccia.Scope.BindingMap.pas

@@ -23,6 +23,7 @@   TLexicalBinding = record
     Value: TGocciaValue;
     DeclarationType: TGocciaDeclarationType;
     Initialized: Boolean;
+    BuiltIn: Boolean;
     { Strict-types annotation enforced on every assignment.  Default
       sltUntyped means no enforcement (typical untyped binding). }
     TypeHint: TGocciaLocalType;