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LibJS: Fix this values in arrow functions

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Also added a large this value test (and strict variant) to ensure this
values have no regressions.
This commit is contained in:
davidot 2021-08-09 15:21:15 +02:00 • committed by Linus Groh
parent 151447bdf7
commit e1573991a3
4 changed files with 889 additions and 4 deletions
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22
Userland/Libraries/LibJS/Runtime/VM.cpp
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@ -11,6 +11,7 @@
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/BoundFunction.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/FinalizationRegistry.h>
#include <LibJS/Runtime/FunctionEnvironment.h>
@ -471,7 +472,7 @@ Value VM::construct(FunctionObject& function, FunctionObject& new_target, Option
if (auto* environment = callee_context.lexical_environment) {
auto& function_environment = verify_cast<FunctionEnvironment>(*environment);
function_environment.set_new_target(&new_target);
if (!this_argument.is_empty()) {
if (!this_argument.is_empty() && function_environment.this_binding_status() != FunctionEnvironment::ThisBindingStatus::Lexical) {
function_environment.bind_this_value(global_object, this_argument);
if (exception())
return {};
@ -603,10 +604,9 @@ void VM::ordinary_call_bind_this(FunctionObject& function, ExecutionContext& cal
auto* local_environment = callee_context.lexical_environment;
auto& function_environment = verify_cast<FunctionEnvironment>(*local_environment);
// This is not completely as the spec describes it however without this stuff breaks
// (Could be related to the note at https://tc39.es/ecma262/#sec-runtime-semantics-instantiatearrowfunctionexpression )
// This almost as the spec describes it however we sometimes don't have callee_realm when dealing
// with proxies and arrow functions however this does seemingly achieve spec like behavior.
if (!callee_realm || this_mode == FunctionObject::ThisMode::Lexical) {
function_environment.bind_this_value(function.global_object(), callee_context.this_value);
return;
}
@ -629,6 +629,20 @@ Value VM::call_internal(FunctionObject& function, Value this_value, Optional<Mar
VERIFY(!exception());
VERIFY(!this_value.is_empty());
if (is<BoundFunction>(function)) {
auto& bound_function = static_cast<BoundFunction&>(function);
auto bound_arguments = bound_function.bound_arguments();
if (arguments.has_value())
bound_arguments.extend(*arguments);
MarkedValueList with_bound_arguments { heap() };
with_bound_arguments.extend(bound_function.bound_arguments());
if (arguments.has_value())
with_bound_arguments.extend(*arguments);
return call_internal(bound_function.target_function(), bound_function.bound_this(), move(with_bound_arguments));
}
ExecutionContext callee_context;
prepare_for_ordinary_call(function, callee_context, js_undefined());
if (exception())