diff --git a/common.gypi b/common.gypi
index 4c856c0912260c..dd79c43462bec9 100644
--- a/common.gypi
+++ b/common.gypi
@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.17',
+    'v8_embedder_string': '-node.18',
 
     ##### V8 defaults for Node.js #####
 
diff --git a/deps/v8/include/v8-script.h b/deps/v8/include/v8-script.h
index 4a8ccab7e28d1d..f15d148b28d85c 100644
--- a/deps/v8/include/v8-script.h
+++ b/deps/v8/include/v8-script.h
@@ -142,10 +142,9 @@ class V8_EXPORT ModuleRequest : public Data {
    *
    * All assertions present in the module request will be supplied in this
    * list, regardless of whether they are supported by the host. Per
-   * https://tc39.es/proposal-import-assertions/#sec-hostgetsupportedimportassertions,
-   * hosts are expected to ignore assertions that they do not support (as
-   * opposed to, for example, triggering an error if an unsupported assertion is
-   * present).
+   * https://tc39.es/proposal-import-attributes/#sec-hostgetsupportedimportattributes,
+   * hosts are expected to throw for assertions that they do not support (as
+   * opposed to, for example, ignoring them).
    */
   Local<FixedArray> GetImportAssertions() const;
 
diff --git a/deps/v8/src/execution/isolate.cc b/deps/v8/src/execution/isolate.cc
index 06c707da96ca34..1c63f0c56bf719 100644
--- a/deps/v8/src/execution/isolate.cc
+++ b/deps/v8/src/execution/isolate.cc
@@ -5156,7 +5156,8 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
 
   // The parser shouldn't have allowed the second argument to import() if
   // the flag wasn't enabled.
-  DCHECK(v8_flags.harmony_import_assertions);
+  DCHECK(v8_flags.harmony_import_assertions ||
+         v8_flags.harmony_import_attributes);
 
   if (!import_assertions_argument->IsJSReceiver()) {
     this->Throw(
@@ -5166,18 +5167,35 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
 
   Handle<JSReceiver> import_assertions_argument_receiver =
       Handle<JSReceiver>::cast(import_assertions_argument);
-  Handle<Name> key = factory()->assert_string();
 
   Handle<Object> import_assertions_object;
-  if (!JSReceiver::GetProperty(this, import_assertions_argument_receiver, key)
-           .ToHandle(&import_assertions_object)) {
-    // This can happen if the property has a getter function that throws
-    // an error.
-    return MaybeHandle<FixedArray>();
+
+  if (v8_flags.harmony_import_attributes) {
+    Handle<Name> with_key = factory()->with_string();
+    if (!JSReceiver::GetProperty(this, import_assertions_argument_receiver,
+                                 with_key)
+             .ToHandle(&import_assertions_object)) {
+      // This can happen if the property has a getter function that throws
+      // an error.
+      return MaybeHandle<FixedArray>();
+    }
   }
 
-  // If there is no 'assert' option in the options bag, it's not an error. Just
-  // do the import() as if no assertions were provided.
+  if (v8_flags.harmony_import_assertions &&
+      (!v8_flags.harmony_import_attributes ||
+       import_assertions_object->IsUndefined())) {
+    Handle<Name> assert_key = factory()->assert_string();
+    if (!JSReceiver::GetProperty(this, import_assertions_argument_receiver,
+                                 assert_key)
+             .ToHandle(&import_assertions_object)) {
+      // This can happen if the property has a getter function that throws
+      // an error.
+      return MaybeHandle<FixedArray>();
+    }
+  }
+
+  // If there is no 'with' or 'assert' option in the options bag, it's not an
+  // error. Just do the import() as if no assertions were provided.
   if (import_assertions_object->IsUndefined()) return import_assertions_array;
 
   if (!import_assertions_object->IsJSReceiver()) {
@@ -5199,6 +5217,8 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
     return MaybeHandle<FixedArray>();
   }
 
+  bool has_non_string_attribute = false;
+
   // The assertions will be passed to the host in the form: [key1,
   // value1, key2, value2, ...].
   constexpr size_t kAssertionEntrySizeForDynamicImport = 2;
@@ -5216,9 +5236,7 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
     }
 
     if (!assertion_value->IsString()) {
-      this->Throw(*factory()->NewTypeError(
-          MessageTemplate::kNonStringImportAssertionValue));
-      return MaybeHandle<FixedArray>();
+      has_non_string_attribute = true;
     }
 
     import_assertions_array->set((i * kAssertionEntrySizeForDynamicImport),
@@ -5227,6 +5245,12 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
                                  *assertion_value);
   }
 
+  if (has_non_string_attribute) {
+    this->Throw(*factory()->NewTypeError(
+        MessageTemplate::kNonStringImportAssertionValue));
+    return MaybeHandle<FixedArray>();
+  }
+
   return import_assertions_array;
 }
 
diff --git a/deps/v8/src/flags/flag-definitions.h b/deps/v8/src/flags/flag-definitions.h
index 8a3ab897c67e98..1bb489833b81f8 100644
--- a/deps/v8/src/flags/flag-definitions.h
+++ b/deps/v8/src/flags/flag-definitions.h
@@ -235,6 +235,7 @@ DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
 
 // Features that are still work in progress (behind individual flags).
 #define HARMONY_INPROGRESS_BASE(V)                                             \
+  V(harmony_import_attributes, "harmony import attributes")                    \
   V(harmony_weak_refs_with_cleanup_some,                                       \
     "harmony weak references with FinalizationRegistry.prototype.cleanupSome") \
   V(harmony_temporal, "Temporal")                                              \
diff --git a/deps/v8/src/init/bootstrapper.cc b/deps/v8/src/init/bootstrapper.cc
index 69d01ff33902aa..c468c502e703df 100644
--- a/deps/v8/src/init/bootstrapper.cc
+++ b/deps/v8/src/init/bootstrapper.cc
@@ -4523,6 +4523,7 @@ void Genesis::InitializeConsole(Handle<JSObject> extras_binding) {
   void Genesis::InitializeGlobal_##id() {}
 
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_import_assertions)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_import_attributes)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_symbol_as_weakmap_key)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_rab_gsab_transfer)
 
diff --git a/deps/v8/src/init/heap-symbols.h b/deps/v8/src/init/heap-symbols.h
index 5388b88d4e7599..1ca46fdc81faa4 100644
--- a/deps/v8/src/init/heap-symbols.h
+++ b/deps/v8/src/init/heap-symbols.h
@@ -462,6 +462,7 @@
   V(_, week_string, "week")                                          \
   V(_, weeks_string, "weeks")                                        \
   V(_, weekOfYear_string, "weekOfYear")                              \
+  V(_, with_string, "with")                                          \
   V(_, word_string, "word")                                          \
   V(_, yearMonthFromFields_string, "yearMonthFromFields")            \
   V(_, year_string, "year")                                          \
diff --git a/deps/v8/src/parsing/parser-base.h b/deps/v8/src/parsing/parser-base.h
index ff5af7dfec9204..cfba92d7e884b8 100644
--- a/deps/v8/src/parsing/parser-base.h
+++ b/deps/v8/src/parsing/parser-base.h
@@ -3774,7 +3774,9 @@ ParserBase<Impl>::ParseImportExpressions() {
   AcceptINScope scope(this, true);
   ExpressionT specifier = ParseAssignmentExpressionCoverGrammar();
 
-  if (v8_flags.harmony_import_assertions && Check(Token::COMMA)) {
+  if ((v8_flags.harmony_import_assertions ||
+       v8_flags.harmony_import_attributes) &&
+      Check(Token::COMMA)) {
     if (Check(Token::RPAREN)) {
       // A trailing comma allowed after the specifier.
       return factory()->NewImportCallExpression(specifier, pos);
diff --git a/deps/v8/src/parsing/parser.cc b/deps/v8/src/parsing/parser.cc
index 6886e037ac2f97..336d88b2ea195b 100644
--- a/deps/v8/src/parsing/parser.cc
+++ b/deps/v8/src/parsing/parser.cc
@@ -1344,27 +1344,28 @@ ZonePtrList<const Parser::NamedImport>* Parser::ParseNamedImports(int pos) {
 }
 
 ImportAssertions* Parser::ParseImportAssertClause() {
-  // AssertClause :
-  //    assert '{' '}'
-  //    assert '{' AssertEntries '}'
+  // WithClause :
+  //    with '{' '}'
+  //    with '{' WithEntries ','? '}'
 
-  // AssertEntries :
-  //    IdentifierName: AssertionKey
-  //    IdentifierName: AssertionKey , AssertEntries
+  // WithEntries :
+  //    LiteralPropertyName
+  //    LiteralPropertyName ':' StringLiteral , WithEntries
 
-  // AssertionKey :
-  //     IdentifierName
-  //     StringLiteral
+  // (DEPRECATED)
+  // AssertClause :
+  //    assert '{' '}'
+  //    assert '{' WithEntries ','? '}'
 
   auto import_assertions = zone()->New<ImportAssertions>(zone());
 
-  if (!v8_flags.harmony_import_assertions) {
-    return import_assertions;
-  }
-
-  // Assert clause is optional, and cannot be preceded by a LineTerminator.
-  if (scanner()->HasLineTerminatorBeforeNext() ||
-      !CheckContextualKeyword(ast_value_factory()->assert_string())) {
+  if (v8_flags.harmony_import_attributes && Check(Token::WITH)) {
+    // 'with' keyword consumed
+  } else if (v8_flags.harmony_import_assertions &&
+             !scanner()->HasLineTerminatorBeforeNext() &&
+             CheckContextualKeyword(ast_value_factory()->assert_string())) {
+    // 'assert' keyword consumed
+  } else {
     return import_assertions;
   }
 
@@ -1372,8 +1373,12 @@ ImportAssertions* Parser::ParseImportAssertClause() {
 
   while (peek() != Token::RBRACE) {
     const AstRawString* attribute_key = nullptr;
-    if (Check(Token::STRING)) {
+    if (Check(Token::STRING) || Check(Token::SMI)) {
       attribute_key = GetSymbol();
+    } else if (Check(Token::NUMBER)) {
+      attribute_key = GetNumberAsSymbol();
+    } else if (Check(Token::BIGINT)) {
+      attribute_key = GetBigIntAsSymbol();
     } else {
       attribute_key = ParsePropertyName();
     }
diff --git a/deps/v8/src/roots/static-roots.h b/deps/v8/src/roots/static-roots.h
index df53f43736888f..16729572de88fc 100644
--- a/deps/v8/src/roots/static-roots.h
+++ b/deps/v8/src/roots/static-roots.h
@@ -693,82 +693,83 @@ struct StaticReadOnlyRoot {
   static constexpr Tagged_t kweek_string = 0x5a55;
   static constexpr Tagged_t kweeks_string = 0x5a65;
   static constexpr Tagged_t kweekOfYear_string = 0x5a79;
-  static constexpr Tagged_t kword_string = 0x5a91;
-  static constexpr Tagged_t kyearMonthFromFields_string = 0x5aa1;
-  static constexpr Tagged_t kyear_string = 0x5ac1;
-  static constexpr Tagged_t kyears_string = 0x5ad1;
-  static constexpr Tagged_t kUninitializedValue = 0x5af5;
-  static constexpr Tagged_t kArgumentsMarker = 0x5b2d;
-  static constexpr Tagged_t kTerminationException = 0x5b65;
-  static constexpr Tagged_t kException = 0x5ba5;
-  static constexpr Tagged_t kOptimizedOut = 0x5bc1;
-  static constexpr Tagged_t kStaleRegister = 0x5bf9;
-  static constexpr Tagged_t kSelfReferenceMarker = 0x5c31;
-  static constexpr Tagged_t kBasicBlockCountersMarker = 0x5c71;
-  static constexpr Tagged_t karray_buffer_wasm_memory_symbol = 0x5cb5;
-  static constexpr Tagged_t kcall_site_info_symbol = 0x5cc5;
-  static constexpr Tagged_t kconsole_context_id_symbol = 0x5cd5;
-  static constexpr Tagged_t kconsole_context_name_symbol = 0x5ce5;
-  static constexpr Tagged_t kclass_fields_symbol = 0x5cf5;
-  static constexpr Tagged_t kclass_positions_symbol = 0x5d05;
-  static constexpr Tagged_t kerror_end_pos_symbol = 0x5d15;
-  static constexpr Tagged_t kerror_script_symbol = 0x5d25;
-  static constexpr Tagged_t kerror_stack_symbol = 0x5d35;
-  static constexpr Tagged_t kerror_start_pos_symbol = 0x5d45;
-  static constexpr Tagged_t kfrozen_symbol = 0x5d55;
-  static constexpr Tagged_t kinterpreter_trampoline_symbol = 0x5d65;
-  static constexpr Tagged_t knative_context_index_symbol = 0x5d75;
-  static constexpr Tagged_t knonextensible_symbol = 0x5d85;
-  static constexpr Tagged_t kpromise_debug_marker_symbol = 0x5d95;
-  static constexpr Tagged_t kpromise_debug_message_symbol = 0x5da5;
-  static constexpr Tagged_t kpromise_forwarding_handler_symbol = 0x5db5;
-  static constexpr Tagged_t kpromise_handled_by_symbol = 0x5dc5;
-  static constexpr Tagged_t kpromise_awaited_by_symbol = 0x5dd5;
-  static constexpr Tagged_t kregexp_result_names_symbol = 0x5de5;
-  static constexpr Tagged_t kregexp_result_regexp_input_symbol = 0x5df5;
-  static constexpr Tagged_t kregexp_result_regexp_last_index_symbol = 0x5e05;
-  static constexpr Tagged_t ksealed_symbol = 0x5e15;
-  static constexpr Tagged_t kstrict_function_transition_symbol = 0x5e25;
+  static constexpr Tagged_t kwith_string = 0x5a91;
+  static constexpr Tagged_t kword_string = 0x5aa1;
+  static constexpr Tagged_t kyearMonthFromFields_string = 0x5ab1;
+  static constexpr Tagged_t kyear_string = 0x5ad1;
+  static constexpr Tagged_t kyears_string = 0x5ae1;
+  static constexpr Tagged_t kUninitializedValue = 0x5b05;
+  static constexpr Tagged_t kArgumentsMarker = 0x5b3d;
+  static constexpr Tagged_t kTerminationException = 0x5b75;
+  static constexpr Tagged_t kException = 0x5bb5;
+  static constexpr Tagged_t kOptimizedOut = 0x5bd1;
+  static constexpr Tagged_t kStaleRegister = 0x5c09;
+  static constexpr Tagged_t kSelfReferenceMarker = 0x5c41;
+  static constexpr Tagged_t kBasicBlockCountersMarker = 0x5c81;
+  static constexpr Tagged_t karray_buffer_wasm_memory_symbol = 0x5cc5;
+  static constexpr Tagged_t kcall_site_info_symbol = 0x5cd5;
+  static constexpr Tagged_t kconsole_context_id_symbol = 0x5ce5;
+  static constexpr Tagged_t kconsole_context_name_symbol = 0x5cf5;
+  static constexpr Tagged_t kclass_fields_symbol = 0x5d05;
+  static constexpr Tagged_t kclass_positions_symbol = 0x5d15;
+  static constexpr Tagged_t kerror_end_pos_symbol = 0x5d25;
+  static constexpr Tagged_t kerror_script_symbol = 0x5d35;
+  static constexpr Tagged_t kerror_stack_symbol = 0x5d45;
+  static constexpr Tagged_t kerror_start_pos_symbol = 0x5d55;
+  static constexpr Tagged_t kfrozen_symbol = 0x5d65;
+  static constexpr Tagged_t kinterpreter_trampoline_symbol = 0x5d75;
+  static constexpr Tagged_t knative_context_index_symbol = 0x5d85;
+  static constexpr Tagged_t knonextensible_symbol = 0x5d95;
+  static constexpr Tagged_t kpromise_debug_marker_symbol = 0x5da5;
+  static constexpr Tagged_t kpromise_debug_message_symbol = 0x5db5;
+  static constexpr Tagged_t kpromise_forwarding_handler_symbol = 0x5dc5;
+  static constexpr Tagged_t kpromise_handled_by_symbol = 0x5dd5;
+  static constexpr Tagged_t kpromise_awaited_by_symbol = 0x5de5;
+  static constexpr Tagged_t kregexp_result_names_symbol = 0x5df5;
+  static constexpr Tagged_t kregexp_result_regexp_input_symbol = 0x5e05;
+  static constexpr Tagged_t kregexp_result_regexp_last_index_symbol = 0x5e15;
+  static constexpr Tagged_t ksealed_symbol = 0x5e25;
+  static constexpr Tagged_t kstrict_function_transition_symbol = 0x5e35;
   static constexpr Tagged_t ktemplate_literal_function_literal_id_symbol =
-      0x5e35;
-  static constexpr Tagged_t ktemplate_literal_slot_id_symbol = 0x5e45;
-  static constexpr Tagged_t kwasm_exception_tag_symbol = 0x5e55;
-  static constexpr Tagged_t kwasm_exception_values_symbol = 0x5e65;
-  static constexpr Tagged_t kwasm_uncatchable_symbol = 0x5e75;
-  static constexpr Tagged_t kwasm_wrapped_object_symbol = 0x5e85;
-  static constexpr Tagged_t kwasm_debug_proxy_cache_symbol = 0x5e95;
-  static constexpr Tagged_t kwasm_debug_proxy_names_symbol = 0x5ea5;
-  static constexpr Tagged_t kasync_iterator_symbol = 0x5eb5;
-  static constexpr Tagged_t kintl_fallback_symbol = 0x5ee5;
-  static constexpr Tagged_t kmatch_all_symbol = 0x5f1d;
-  static constexpr Tagged_t kmatch_symbol = 0x5f49;
-  static constexpr Tagged_t ksearch_symbol = 0x5f71;
-  static constexpr Tagged_t ksplit_symbol = 0x5f9d;
-  static constexpr Tagged_t kto_primitive_symbol = 0x5fc5;
-  static constexpr Tagged_t kunscopables_symbol = 0x5ff5;
-  static constexpr Tagged_t khas_instance_symbol = 0x6025;
-  static constexpr Tagged_t kto_string_tag_symbol = 0x6055;
-  static constexpr Tagged_t kconstructor_string = 0x60ad;
-  static constexpr Tagged_t knext_string = 0x60c5;
-  static constexpr Tagged_t kresolve_string = 0x60d5;
-  static constexpr Tagged_t kthen_string = 0x60e9;
-  static constexpr Tagged_t kiterator_symbol = 0x60f9;
-  static constexpr Tagged_t kreplace_symbol = 0x6109;
-  static constexpr Tagged_t kspecies_symbol = 0x6119;
-  static constexpr Tagged_t kis_concat_spreadable_symbol = 0x6129;
-  static constexpr Tagged_t kEmptySlowElementDictionary = 0x6139;
-  static constexpr Tagged_t kEmptySymbolTable = 0x615d;
-  static constexpr Tagged_t kEmptyOrderedHashMap = 0x6179;
-  static constexpr Tagged_t kEmptyOrderedHashSet = 0x618d;
-  static constexpr Tagged_t kEmptyFeedbackMetadata = 0x61a1;
-  static constexpr Tagged_t kGlobalThisBindingScopeInfo = 0x61ad;
-  static constexpr Tagged_t kEmptyFunctionScopeInfo = 0x61cd;
-  static constexpr Tagged_t kNativeScopeInfo = 0x61f1;
-  static constexpr Tagged_t kShadowRealmScopeInfo = 0x6209;
+      0x5e45;
+  static constexpr Tagged_t ktemplate_literal_slot_id_symbol = 0x5e55;
+  static constexpr Tagged_t kwasm_exception_tag_symbol = 0x5e65;
+  static constexpr Tagged_t kwasm_exception_values_symbol = 0x5e75;
+  static constexpr Tagged_t kwasm_uncatchable_symbol = 0x5e85;
+  static constexpr Tagged_t kwasm_wrapped_object_symbol = 0x5e95;
+  static constexpr Tagged_t kwasm_debug_proxy_cache_symbol = 0x5ea5;
+  static constexpr Tagged_t kwasm_debug_proxy_names_symbol = 0x5eb5;
+  static constexpr Tagged_t kasync_iterator_symbol = 0x5ec5;
+  static constexpr Tagged_t kintl_fallback_symbol = 0x5ef5;
+  static constexpr Tagged_t kmatch_all_symbol = 0x5f2d;
+  static constexpr Tagged_t kmatch_symbol = 0x5f59;
+  static constexpr Tagged_t ksearch_symbol = 0x5f81;
+  static constexpr Tagged_t ksplit_symbol = 0x5fad;
+  static constexpr Tagged_t kto_primitive_symbol = 0x5fd5;
+  static constexpr Tagged_t kunscopables_symbol = 0x6005;
+  static constexpr Tagged_t khas_instance_symbol = 0x6035;
+  static constexpr Tagged_t kto_string_tag_symbol = 0x6065;
+  static constexpr Tagged_t kconstructor_string = 0x60bd;
+  static constexpr Tagged_t knext_string = 0x60d5;
+  static constexpr Tagged_t kresolve_string = 0x60e5;
+  static constexpr Tagged_t kthen_string = 0x60f9;
+  static constexpr Tagged_t kiterator_symbol = 0x6109;
+  static constexpr Tagged_t kreplace_symbol = 0x6119;
+  static constexpr Tagged_t kspecies_symbol = 0x6129;
+  static constexpr Tagged_t kis_concat_spreadable_symbol = 0x6139;
+  static constexpr Tagged_t kEmptySlowElementDictionary = 0x6149;
+  static constexpr Tagged_t kEmptySymbolTable = 0x616d;
+  static constexpr Tagged_t kEmptyOrderedHashMap = 0x6189;
+  static constexpr Tagged_t kEmptyOrderedHashSet = 0x619d;
+  static constexpr Tagged_t kEmptyFeedbackMetadata = 0x61b1;
+  static constexpr Tagged_t kGlobalThisBindingScopeInfo = 0x61bd;
+  static constexpr Tagged_t kEmptyFunctionScopeInfo = 0x61dd;
+  static constexpr Tagged_t kNativeScopeInfo = 0x6201;
+  static constexpr Tagged_t kShadowRealmScopeInfo = 0x6219;
   static constexpr Tagged_t kWasmNull = 0xfffd;
 };
 
-static constexpr std::array<Tagged_t, 738> StaticReadOnlyRootsPointerTable = {
+static constexpr std::array<Tagged_t, 739> StaticReadOnlyRootsPointerTable = {
     StaticReadOnlyRoot::kFreeSpaceMap,
     StaticReadOnlyRoot::kOnePointerFillerMap,
     StaticReadOnlyRoot::kTwoPointerFillerMap,
@@ -1365,6 +1366,7 @@ static constexpr std::array<Tagged_t, 738> StaticReadOnlyRootsPointerTable = {
     StaticReadOnlyRoot::kweek_string,
     StaticReadOnlyRoot::kweeks_string,
     StaticReadOnlyRoot::kweekOfYear_string,
+    StaticReadOnlyRoot::kwith_string,
     StaticReadOnlyRoot::kword_string,
     StaticReadOnlyRoot::kyearMonthFromFields_string,
     StaticReadOnlyRoot::kyear_string,
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-1.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-1.mjs
new file mode 100644
index 00000000000000..3cf6bac870b80f
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-1.mjs
@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import { life } from 'modules-skip-1.mjs' with { };
+
+assertEquals(42, life());
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-2.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-2.mjs
new file mode 100644
index 00000000000000..63f5859ca0f1d0
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-2.mjs
@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import json from 'modules-skip-1.json' with { type: 'json' };
+
+assertEquals(42, json.life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-3.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-3.mjs
new file mode 100644
index 00000000000000..34db1852367c19
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-3.mjs
@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import {life} from 'modules-skip-imports-json-1.mjs';
+
+assertEquals(42, life());
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-4.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-4.mjs
new file mode 100644
index 00000000000000..66bdc11c359ed4
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-4.mjs
@@ -0,0 +1,9 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-import-attributes
+
+import json from 'modules-skip-1.json' with { type: 'json', notARealAssertion: 'value'};
+
+assertEquals(42, json.life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-1.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-1.mjs
new file mode 100644
index 00000000000000..644fc96a6e2111
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-1.mjs
@@ -0,0 +1,12 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.mjs', { }).then(namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-10.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-10.mjs
new file mode 100644
index 00000000000000..972fbed24bfff2
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-10.mjs
@@ -0,0 +1,19 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var result1;
+var result2;
+import('modules-skip-1.json', { get with() { throw 'bad \'with\' getter!'; } }).then(
+    () => assertUnreachable('Should have failed due to throwing getter'),
+    error => result1 = error);
+import('modules-skip-1.json', { with: { get assertionKey() { throw 'bad \'assertionKey\' getter!'; } } }).then(
+    () => assertUnreachable('Should have failed due to throwing getter'),
+    error => result2 = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals('bad \'with\' getter!', result1);
+assertEquals('bad \'assertionKey\' getter!', result2);
\ No newline at end of file
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-11.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-11.mjs
new file mode 100644
index 00000000000000..c39a5f9d4e2e06
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-11.mjs
@@ -0,0 +1,19 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes --harmony-top-level-await
+
+var life1;
+var life2;
+import('modules-skip-1.json', { with: { type: 'json' } }).then(
+    namespace => life1 = namespace.default.life);
+
+// Try loading the same module a second time.
+import('modules-skip-1.json', { with: { type: 'json' } }).then(
+    namespace => life2 = namespace.default.life);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life1);
+assertEquals(42, life2);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-12.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-12.mjs
new file mode 100644
index 00000000000000..1d8fb21a502237
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-12.mjs
@@ -0,0 +1,26 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+let result1;
+let result2;
+
+let badAssertProxy1 = new Proxy({}, { ownKeys() { throw "bad ownKeys!"; } });
+import('./modules-skip-1.mjs', { with: badAssertProxy1 }).then(
+    () => assertUnreachable('Should have failed due to throwing ownKeys'),
+    error => result1 = error);
+
+let badAssertProxy2 = new Proxy(
+    {foo: "bar"},
+    { getOwnPropertyDescriptor() { throw "bad getOwnPropertyDescriptor!"; } });
+import('./modules-skip-1.mjs', { with: badAssertProxy2 }).then(
+    () => assertUnreachable(
+        'Should have failed due to throwing getOwnPropertyDescriptor'),
+    error => result2 = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals('bad ownKeys!', result1);
+assertEquals('bad getOwnPropertyDescriptor!', result2);
\ No newline at end of file
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-13.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-13.mjs
new file mode 100644
index 00000000000000..6e23c07c281db1
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-13.mjs
@@ -0,0 +1,26 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+let getters = 0;
+let result;
+
+import('./modules-skip-1.mjs', { with: {
+    get attr1() {
+        getters++;
+        return {};
+    },
+    get attr2() {
+        getters++;
+        return {};
+    },
+} }).then(
+    () => assertUnreachable('Should have failed due to invalid attributes values'),
+    error => result = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(2, getters);
+assertInstanceof(result, TypeError);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-2.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-2.mjs
new file mode 100644
index 00000000000000..b8e59fb0bfe9c3
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-2.mjs
@@ -0,0 +1,13 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.mjs', { with: { } }).then(
+    namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-3.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-3.mjs
new file mode 100644
index 00000000000000..da570eb2836edd
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-3.mjs
@@ -0,0 +1,13 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.json', { with: { type: 'json' } }).then(
+    namespace => life = namespace.default.life);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-4.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-4.mjs
new file mode 100644
index 00000000000000..fff6fe2bbef84c
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-4.mjs
@@ -0,0 +1,14 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var result;
+import('modules-skip-1.json', { with: { type: 'notARealType' } }).then(
+    () => assertUnreachable('Should have failed due to bad module type'),
+    error => result = error.message);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals('Invalid module type was asserted', result);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-5.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-5.mjs
new file mode 100644
index 00000000000000..cdb1567c330764
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-5.mjs
@@ -0,0 +1,12 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-imports-json-1.mjs',).then(namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-6.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-6.mjs
new file mode 100644
index 00000000000000..ad84e3edd5ffe1
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-6.mjs
@@ -0,0 +1,18 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.json', { with: { type: 'json', notARealAssertion: 'value' } }).then(
+    namespace => life = namespace.default.life);
+
+var life2;
+import('modules-skip-1.json', { with: { 0: 'value', type: 'json' } }).then(
+    namespace => life2 = namespace.default.life);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
+assertEquals(42, life2);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-7.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-7.mjs
new file mode 100644
index 00000000000000..530d833cce5a4d
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-7.mjs
@@ -0,0 +1,63 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var result1;
+var result2;
+var result3;
+var result4;
+var result5;
+var result6;
+var result7;
+var result8;
+var result9;
+var result10;
+import('modules-skip-1.json', null).then(
+    () => assertUnreachable('Should have failed due to non-object parameter'),
+    error => result1 = error.message);
+import('modules-skip-1.json', 7).then(
+    () => assertUnreachable('Should have failed due to non-object parameter'),
+    error => result2 = error.message);
+import('modules-skip-1.json', 'string').then(
+        () => assertUnreachable('Should have failed due to non-object parameter'),
+        error => result3 = error.message);
+import('modules-skip-1.json', { with: null}).then(
+    () => assertUnreachable('Should have failed due to bad with object'),
+    error => result4 = error.message);
+import('modules-skip-1.json', { with: 7}).then(
+    () => assertUnreachable('Should have failed due to bad with object'),
+    error => result5 = error.message);
+import('modules-skip-1.json', { with: 'string'}).then(
+    () => assertUnreachable('Should have failed due to bad with object'),
+    error => result6 = error.message);
+import('modules-skip-1.json', { with: { a: null }}).then(
+    () => assertUnreachable('Should have failed due to bad with object'),
+    error => result7 = error.message);
+import('modules-skip-1.json', { with: { a: undefined }}).then(
+    () => assertUnreachable('Should have failed due to bad assertion value'),
+    error => result8 = error.message);
+import('modules-skip-1.json', { with: { a: 7 }}).then(
+    () => assertUnreachable('Should have failed due to bad assertion value'),
+    error => result9 = error.message);
+    import('modules-skip-1.json', { with: { a: { } }}).then(
+        () => assertUnreachable('Should have failed due to bad assertion value'),
+        error => result10 = error.message);
+
+%PerformMicrotaskCheckpoint();
+
+const argumentNotObjectError = 'The second argument to import() must be an object';
+const assertOptionNotObjectError = 'The \'assert\' option must be an object';
+const assertionValueNotStringError = 'Import assertion value must be a string';
+
+assertEquals(argumentNotObjectError, result1);
+assertEquals(argumentNotObjectError, result2);
+assertEquals(argumentNotObjectError, result3);
+assertEquals(assertOptionNotObjectError, result4);
+assertEquals(assertOptionNotObjectError, result5);
+assertEquals(assertOptionNotObjectError, result6);
+assertEquals(assertionValueNotStringError, result7);
+assertEquals(assertionValueNotStringError, result8);
+assertEquals(assertionValueNotStringError, result9);
+assertEquals(assertionValueNotStringError, result10);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-8.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-8.mjs
new file mode 100644
index 00000000000000..74a4504e253d6a
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-8.mjs
@@ -0,0 +1,13 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.mjs', undefined).then(
+    namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-9.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-9.mjs
new file mode 100644
index 00000000000000..1b56c70df61682
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-9.mjs
@@ -0,0 +1,13 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes
+
+var life;
+import('modules-skip-1.mjs', { with: undefined }).then(
+    namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-assertions-fallback-1.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-assertions-fallback-1.mjs
new file mode 100644
index 00000000000000..3faaf0dccea1c9
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-assertions-fallback-1.mjs
@@ -0,0 +1,15 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes --harmony-import-assertions
+
+var life;
+import('modules-skip-1.mjs', {
+    with: {},
+    get assert() { throw 'Should not read assert'; }
+}).then(namespace => life = namespace.life());
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-assertions-fallback-2.mjs b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-assertions-fallback-2.mjs
new file mode 100644
index 00000000000000..4c83d2fbd716cc
--- /dev/null
+++ b/deps/v8/test/mjsunit/harmony/modules-import-attributes-dynamic-assertions-fallback-2.mjs
@@ -0,0 +1,15 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-attributes --harmony-import-assertions
+
+var life;
+import('modules-skip-1.json', {
+    with: undefined,
+    assert: { type: 'json' }
+}).then(namespace => life = namespace.default.life);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals(42, life);
diff --git a/deps/v8/test/unittests/parser/parsing-unittest.cc b/deps/v8/test/unittests/parser/parsing-unittest.cc
index 9048d7f1faf674..24e178e2ca5eb6 100644
--- a/deps/v8/test/unittests/parser/parsing-unittest.cc
+++ b/deps/v8/test/unittests/parser/parsing-unittest.cc
@@ -4876,6 +4876,11 @@ TEST_F(ParsingTest, BasicImportAssertionParsing) {
     "import { a as b } from 'm.js' assert { \nc: 'd'};",
     "import { a as b } from 'm.js' assert { c:\n 'd'};",
     "import { a as b } from 'm.js' assert { c:'d'\n};",
+
+    "import { a as b } from 'm.js' assert { 0: 'b', };",
+    "import { a as b } from 'm.js' assert { 0n: 'b', };",
+    "import { a as b } from 'm.js' assert { '0': 'b', };",
+    "import { a as b } from 'm.js' assert { 0.0: 'b', };",
   };
   // clang-format on
 
@@ -4943,10 +4948,234 @@ TEST_F(ParsingTest, ImportAssertionParsingErrors) {
     "import { a } from 'm.js' assert { , b: c };",
     "import { a } from 'm.js' assert { a: 'b', a: 'c' };",
     "import { a } from 'm.js' assert { a: 'b', 'a': 'c' };",
+
+    "import { a } from 'm.js' assert { 0: 'b', '0': 'c' };",
+    "import { a } from 'm.js' assert { 0n: 'b', '0': 'c' };",
+    "import { a } from 'm.js' assert { 0: 'b', 0n: 'c' };",
+    "import { a } from 'm.js' assert { 0: 'b', 0.0: 'c' };",
+    "import { a } from 'm.js' assert { '0': 'b', 0n: 'c' };",
+
+    "import 'm.js' with { a: 'b' };"
+  };
+  // clang-format on
+
+  i::v8_flags.harmony_import_assertions = true;
+  i::Isolate* isolate = i_isolate();
+  i::Factory* factory = isolate->factory();
+
+  isolate->stack_guard()->SetStackLimit(i::GetCurrentStackPosition() -
+                                        128 * 1024);
+
+  for (unsigned i = 0; i < arraysize(kErrorSources); ++i) {
+    i::Handle<i::String> source =
+        factory->NewStringFromAsciiChecked(kErrorSources[i]);
+
+    i::Handle<i::Script> script = factory->NewScript(source);
+    i::UnoptimizedCompileState compile_state;
+    i::ReusableUnoptimizedCompileState reusable_state(isolate);
+    i::UnoptimizedCompileFlags flags =
+        i::UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
+    flags.set_is_module(true);
+    i::ParseInfo info(isolate, flags, &compile_state, &reusable_state);
+    CHECK(!i::parsing::ParseProgram(&info, script, isolate,
+                                    parsing::ReportStatisticsMode::kYes));
+    CHECK(info.pending_error_handler()->has_pending_error());
+  }
+}
+
+TEST_F(ParsingTest, BasicImportAttributesParsing) {
+  // clang-format off
+  const char* kSources[] = {
+    "import { a as b } from 'm.js' with { };",
+    "import n from 'n.js' with { };",
+    "export { a as b } from 'm.js' with { };",
+    "export * from 'm.js' with { };",
+    "import 'm.js' with { };",
+    "import * as foo from 'bar.js' with { };",
+
+    "import { a as b } from 'm.js' with { a: 'b' };",
+    "import { a as b } from 'm.js' with { c: 'd' };",
+    "import { a as b } from 'm.js' with { 'c': 'd' };",
+    "import { a as b } from 'm.js' with { a: 'b', 'c': 'd', e: 'f' };",
+    "import { a as b } from 'm.js' with { 'c': 'd', };",
+    "import n from 'n.js' with { 'c': 'd' };",
+    "export { a as b } from 'm.js' with { 'c': 'd' };",
+    "export * from 'm.js' with { 'c': 'd' };",
+    "import 'm.js' with { 'c': 'd' };",
+    "import * as foo from 'bar.js' with { 'c': 'd' };",
+
+    "import { a as b } from 'm.js' with { \nc: 'd'};",
+    "import { a as b } from 'm.js' with { c:\n 'd'};",
+    "import { a as b } from 'm.js' with { c:'d'\n};",
+
+    "import { a as b } from 'm.js' with { 0: 'b', };",
+    "import { a as b } from 'm.js' with { 0n: 'b', };",
+    "import { a as b } from 'm.js' with { '0': 'b', };",
+    "import { a as b } from 'm.js' with { 0.0: 'b', };",
+
+    "import 'm.js'\n with { };",
+    "import 'm.js' \nwith { };",
+    "import { a } from 'm.js'\n with { };",
+    "export * from 'm.js'\n with { };"
+  };
+  // clang-format on
+
+  i::v8_flags.harmony_import_attributes = true;
+  i::Isolate* isolate = i_isolate();
+  i::Factory* factory = isolate->factory();
+
+  isolate->stack_guard()->SetStackLimit(i::GetCurrentStackPosition() -
+                                        128 * 1024);
+
+  for (unsigned i = 0; i < arraysize(kSources); ++i) {
+    i::Handle<i::String> source =
+        factory->NewStringFromAsciiChecked(kSources[i]);
+
+    // Show that parsing as a module works
+    {
+      i::Handle<i::Script> script = factory->NewScript(source);
+      i::UnoptimizedCompileState compile_state;
+      i::ReusableUnoptimizedCompileState reusable_state(isolate);
+      i::UnoptimizedCompileFlags flags =
+          i::UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
+      flags.set_is_module(true);
+      i::ParseInfo info(isolate, flags, &compile_state, &reusable_state);
+      CHECK_PARSE_PROGRAM(&info, script, isolate);
+    }
+
+    // And that parsing a script does not.
+    {
+      i::UnoptimizedCompileState compile_state;
+      i::ReusableUnoptimizedCompileState reusable_state(isolate);
+      i::Handle<i::Script> script = factory->NewScript(source);
+      i::UnoptimizedCompileFlags flags =
+          i::UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
+      i::ParseInfo info(isolate, flags, &compile_state, &reusable_state);
+      CHECK(!i::parsing::ParseProgram(&info, script, isolate,
+                                      parsing::ReportStatisticsMode::kYes));
+      CHECK(info.pending_error_handler()->has_pending_error());
+    }
+  }
+}
+
+TEST_F(ParsingTest, ImportAttributesParsingErrors) {
+  // clang-format off
+  const char* kErrorSources[] = {
+    "import { a } from 'm.js' with {;",
+    "import { a } from 'm.js' with };",
+    "import { a } from 'm.js' , with { };",
+    "import { a } from 'm.js' with , { };",
+    "import { a } from 'm.js' with { , };",
+    "import { a } from 'm.js' with { b };",
+    "import { a } from 'm.js' with { 'b' };",
+    "import { a } from 'm.js' with { for };",
+    "import { a } from 'm.js' with { with };",
+    "export { a } with { };",
+    "export * with { };",
+
+    "import { a } from 'm.js' with { 1: 2 };",
+    "import { a } from 'm.js' with { b: c };",
+    "import { a } from 'm.js' with { 'b': c };",
+    "import { a } from 'm.js' with { , b: c };",
+    "import { a } from 'm.js' with { a: 'b', a: 'c' };",
+    "import { a } from 'm.js' with { a: 'b', 'a': 'c' };",
+
+    "import { a } from 'm.js' with { 0: 'b', '0': 'c' };",
+    "import { a } from 'm.js' with { 0n: 'b', '0': 'c' };",
+    "import { a } from 'm.js' with { 0: 'b', 0n: 'c' };",
+    "import { a } from 'm.js' with { 0: 'b', 0.0: 'c' };",
+    "import { a } from 'm.js' with { '0': 'b', 0n: 'c' };",
+
+    "import 'm.js' assert { a: 'b' };"
+  };
+  // clang-format on
+
+  i::v8_flags.harmony_import_assertions = false;
+  i::v8_flags.harmony_import_attributes = true;
+  i::Isolate* isolate = i_isolate();
+  i::Factory* factory = isolate->factory();
+
+  isolate->stack_guard()->SetStackLimit(i::GetCurrentStackPosition() -
+                                        128 * 1024);
+
+  for (unsigned i = 0; i < arraysize(kErrorSources); ++i) {
+    i::Handle<i::String> source =
+        factory->NewStringFromAsciiChecked(kErrorSources[i]);
+
+    i::Handle<i::Script> script = factory->NewScript(source);
+    i::UnoptimizedCompileState compile_state;
+    i::ReusableUnoptimizedCompileState reusable_state(isolate);
+    i::UnoptimizedCompileFlags flags =
+        i::UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
+    flags.set_is_module(true);
+    i::ParseInfo info(isolate, flags, &compile_state, &reusable_state);
+    CHECK(!i::parsing::ParseProgram(&info, script, isolate,
+                                    parsing::ReportStatisticsMode::kYes));
+    CHECK(info.pending_error_handler()->has_pending_error());
+  }
+}
+
+TEST_F(ParsingTest, BasicImportAttributesAndAssertionsParsing) {
+  // clang-format off
+  const char* kSources[] = {
+    "import { a } from 'm.js' assert { };",
+    "import { a } from 'm.js' with { };",
+    "import { a } from 'm.js'\n with { };",
+  };
+  // clang-format on
+
+  i::v8_flags.harmony_import_assertions = true;
+  i::v8_flags.harmony_import_attributes = true;
+  i::Isolate* isolate = i_isolate();
+  i::Factory* factory = isolate->factory();
+
+  isolate->stack_guard()->SetStackLimit(i::GetCurrentStackPosition() -
+                                        128 * 1024);
+
+  for (unsigned i = 0; i < arraysize(kSources); ++i) {
+    i::Handle<i::String> source =
+        factory->NewStringFromAsciiChecked(kSources[i]);
+
+    // Show that parsing as a module works
+    {
+      i::Handle<i::Script> script = factory->NewScript(source);
+      i::UnoptimizedCompileState compile_state;
+      i::ReusableUnoptimizedCompileState reusable_state(isolate);
+      i::UnoptimizedCompileFlags flags =
+          i::UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
+      flags.set_is_module(true);
+      i::ParseInfo info(isolate, flags, &compile_state, &reusable_state);
+      CHECK_PARSE_PROGRAM(&info, script, isolate);
+    }
+
+    // And that parsing a script does not.
+    {
+      i::UnoptimizedCompileState compile_state;
+      i::ReusableUnoptimizedCompileState reusable_state(isolate);
+      i::Handle<i::Script> script = factory->NewScript(source);
+      i::UnoptimizedCompileFlags flags =
+          i::UnoptimizedCompileFlags::ForScriptCompile(isolate, *script);
+      i::ParseInfo info(isolate, flags, &compile_state, &reusable_state);
+      CHECK(!i::parsing::ParseProgram(&info, script, isolate,
+                                      parsing::ReportStatisticsMode::kYes));
+      CHECK(info.pending_error_handler()->has_pending_error());
+    }
+  }
+}
+
+TEST_F(ParsingTest, ImportAttributesAndAssertionsParsingErrors) {
+  // clang-format off
+  const char* kErrorSources[] = {
+    "import { a } from 'm.js'\n assert { };",
+    "import { a } from 'm.js' with { } assert { };",
+    "import { a } from 'm.js' with assert { };",
+    "import { a } from 'm.js' assert { } with { };",
+    "import { a } from 'm.js' assert with { };",
   };
   // clang-format on
 
   i::v8_flags.harmony_import_assertions = true;
+  i::v8_flags.harmony_import_attributes = true;
   i::Isolate* isolate = i_isolate();
   i::Factory* factory = isolate->factory();