Add casts that will be needed once Latin1Character is a distinct type

rdar://161524685
https://bugs.webkit.org/show_bug.cgi?id=299706

Reviewed by Geoffrey Garen.

* Source/JavaScriptCore/API/JSScript.mm:
(+[JSScript scriptOfType:memoryMappedFromASCIIFile:withSourceURL:andBytecodeCache:inVirtualMachine:error:]):
Cast to Latin1Character.

* Source/JavaScriptCore/API/JSStringRefCF.cpp:
(JSStringCreateWithCFString): Cast to UInt8.
(JSStringCopyCFString): Ditto.

* Source/JavaScriptCore/inspector/remote/socket/RemoteInspectorSocket.cpp:
(Inspector::RemoteInspector::backendCommands const): Eliminate use of String::adopt.
It doesn't really work for vectors any more, and likely we should remove it to avoid
making a promise we can't keep. It doesn't work with byteCast, which is why we need
to do this here now.

* Source/JavaScriptCore/runtime/JSGenericTypedArrayViewPrototype.cpp:
(JSC::uint8ArrayPrototypeToHex): Cast to uint8_t.

* Source/JavaScriptCore/runtime/LiteralParser.cpp:
(JSC::reviverMode>::Lexer::lexString): Reduce mixing char with Latin1Character a bit.

* Source/WTF/wtf/URLParser.cpp:
(WTF::URLParser::appendNumberToASCIIBuffer): Cast to char.

* Source/WTF/wtf/cf/CFURLExtras.cpp:
(WTF::bytesAsString): Cast to UInt8.
(WTF::isSameOrigin): Cast to Latin1Character.

* Source/WTF/wtf/cf/URLCF.cpp:
(WTF::URL::createCFURL): Cast to UInt8.

* Source/WTF/wtf/cocoa/NSURLExtras.mm:
(WTF::userVisibleString): Cast to Latin1Character.
* Source/WTF/wtf/persistence/PersistentCoders.cpp:
(WTF::Persistence::Coder<String>::encodeForPersistence): Use asBytes.

* Source/WTF/wtf/text/StringBuilder.h:
(WTF::StringBuilder::operator[] const): Cast so the conditional operator
does not mix types.

* Source/WTF/wtf/text/WTFString.cpp:
(WTF::String::String): Cast to Latin1Character.
(WTF::String::ascii const): Cast so the conditional operator does not mix types.

* Source/WTF/wtf/text/cf/StringCF.cpp:
(WTF::String::String): Cast to UInt8.
* Source/WTF/wtf/text/cf/StringImplCF.cpp:
(WTF::StringImpl::createCFString): Ditto.
* Source/WTF/wtf/text/cf/StringViewCF.cpp:
(WTF::StringView::createCFString const): Ditto.
(WTF::StringView::createCFStringWithoutCopying const): Ditto.

* Source/WebCore/Modules/encryptedmedia/InitDataRegistry.cpp:
(WebCore::extractKeyIDsKeyids): Cast to Latin1Character to pass to parseJSON and remove
the unnecessary copy into a temporary String.

* Source/WebCore/Modules/mediastream/PeerConnectionBackend.cpp:
(WebCore::PeerConnectionBackend::handleLogMessage): Cast to uint8_t.
* Source/WebCore/Modules/mediastream/RTCRtpSFrameTransformerCocoa.cpp:
(WebCore::RTCRtpSFrameTransformer::computeSaltKey): Ditto.
(WebCore::createBaseSFrameKey): Ditto.
(WebCore::RTCRtpSFrameTransformer::computeAuthenticationKey): Ditto.
(WebCore::RTCRtpSFrameTransformer::computeEncryptionKey): Ditto.
* Source/WebCore/Modules/mediastream/gstreamer/GStreamerDtlsTransportBackend.cpp:
(WebCore::GStreamerDtlsTransportBackendObserver::stateChanged): Ditto.
* Source/WebCore/Modules/push-api/PushMessageCrypto.cpp:
(WebCore::PushCrypto::decryptAES128GCMPayload): Ditto.
(WebCore::PushCrypto::decryptAESGCMPayload): Ditto.

* Source/WebCore/Modules/websockets/WebSocketHandshake.cpp:
(WebCore::trimInputSample): Cast to Latin1Character.
(WebCore::WebSocketHandshake::readStatusLine): Ditto.

* Source/WebCore/bindings/js/ScriptBufferSourceProvider.h: Cast to Latin1Character.
* Source/WebCore/bindings/js/SerializedScriptValue.cpp:
(WebCore::CloneDeserializer::readString): Ditto.

* Source/WebCore/contentextensions/DFABytecodeInterpreter.cpp:
(WebCore::ContentExtensions::DFABytecodeInterpreter::interpretJumpTable):
Cast so the conditional operator does not mix types.
(WebCore::ContentExtensions::DFABytecodeInterpreter::interpret): Ditto.

* Source/WebCore/crypto/SubtleCrypto.cpp:
(WebCore::SubtleCrypto::unwrapKey): Cast to Latin1Character to pass to JSONParse and remove
the unnecessary copy into a temporary String.

* Source/WebCore/editing/cocoa/WebContentReaderCocoa.mm:
(WebCore::replaceRichContentWithAttachments): Cast to Latin1Character.
* Source/WebCore/fileapi/FileReaderLoader.cpp:
(WebCore::FileReaderLoader::stringResult): Ditto.
* Source/WebCore/html/FTPDirectoryDocument.cpp:
(WebCore::FTPDirectoryDocumentParser::loadDocumentTemplate): Ditto.

* Source/WebCore/html/parser/HTMLEntityParser.cpp:
(WebCore::StringParsingBufferSource::currentCharacter const):
Cast so the conditional operator does not mix types.
* Source/WebCore/html/track/VTTScanner.h:
(WebCore::VTTScanner::currentChar const): Ditto.

* Source/WebCore/html/track/WebVTTParser.cpp:
(WebCore::WebVTTParser::fileFinished): Cast to uint8_t.

* Source/WebCore/loader/FTPDirectoryParser.cpp:
(WebCore::parseOneFTPLine): Cast to Latin1Character.

* Source/WebCore/loader/FormSubmission.cpp:
(WebCore::appendMailtoPostFormDataToURL): Cast to Latin1Character.
(WebCore::FormSubmission::create): Ditto.

* Source/WebCore/loader/TextResourceDecoder.cpp:
(WebCore::findXMLEncoding): Cast to uint8_t.
(WebCore::TextResourceDecoder::checkForCSSCharset): Cast to uint8_t and Latin1Character.
(WebCore::TextResourceDecoder::checkForHeadCharset): Ditto.

* Source/WebCore/loader/cache/CachedScript.cpp:
(WebCore::CachedScript::script): Cast to Latin1Character.
(WebCore::CachedScript::codeBlockHashConcurrently): Ditto.

* Source/WebCore/platform/encryptedmedia/CDMUtilities.cpp:
(WebCore::CDMUtilities::parseJSONObject): Cast to Latin1Character to pass to parseJSON
and remove the unnecessary copy into a temporary String.
* Source/WebCore/platform/graphics/avfoundation/CDMFairPlayStreaming.cpp:
(WebCore::extractSinfData): Ditto.
(WebCore::CDMPrivateFairPlayStreaming::extractKeyIDsMpts): Ditto.

* Source/WebCore/platform/graphics/avfoundation/objc/CDMInstanceFairPlayStreamingAVFObjC.mm:
(WebCore::parseJSONValue): Cast to Latin1Character.
* Source/WebCore/platform/graphics/freetype/FontCacheFreeType.cpp:
(WebCore::fontNameMapName): Ditto.

* Source/WebCore/platform/graphics/gstreamer/eme/CDMThunder.cpp:
(WebCore::ParsedResponseMessage::ParsedResponseMessage): Cast to Latin1Character.
(WebCore::CDMInstanceSessionThunder::loadSession): Ditto.

* Source/WebCore/platform/gstreamer/GStreamerElementHarness.cpp:
(WebCore::MermaidBuilder::span const): Cast to uint8_t.

* Source/WebCore/platform/image-decoders/png/PNGImageDecoder.cpp:
(WebCore::decodingWarning): Cast to char.
(WebCore::PNGImageDecoder::readChunks): Ditto.

* Source/WebCore/platform/mediarecorder/MediaRecorderPrivateMock.cpp:
(WebCore::MediaRecorderPrivateMock::fetchData): Cast to uint8_t.

* Source/WebCore/platform/network/curl/OpenSSLHelper.cpp:
(OpenSSL::BIO::getDataAsString const): Cast to Latin1Character.
(OpenSSL::toString): Ditto.
* Source/WebCore/platform/network/soup/CertificateInfoSoup.cpp:
(WebCore::CertificateInfo::summary const): Ditto.

* Source/WebCore/platform/text/SegmentedString.h:
(WebCore::SegmentedString::Substring::currentCharacter const):
Cast so the conditional operator does not mix types.

* Source/WebCore/testing/MockCDMFactory.cpp:
(WebCore::MockCDM::sanitizeResponse const): Cast to Latin1Character.
(WebCore::MockCDMInstance::setServerCertificate): Ditto.
(WebCore::MockCDMInstanceSession::updateLicense): Ditto.

* Source/WebGPU/WebGPU/Pipeline.mm:
(WebKit::printToFileForPsoRepro): Cast to uint8_t.
* Source/WebKit/NetworkProcess/cache/NetworkCache.cpp:
(WebKit::NetworkCache::Cache::dumpContentsToFile): Ditto.

* Source/WebKit/NetworkProcess/storage/CacheStorageManager.cpp:
(WebKit::readSizeFile): Cast to Latin1Character.

* Source/WebKit/Platform/IPC/DaemonCoders.h:
(WebKit::Daemon::Coder<WTF::String>::encode): Cast to uint8_t.

* Source/WebKit/Shared/API/c/cf/WKStringCF.mm:
(WKStringCopyCFString): Cast to UInt8.

* Source/WebKit/Shared/Cocoa/SandboxExtensionCocoa.mm:
(WebKit::SandboxExtensionImpl::SandboxExtensionImpl): Cast to Latin1Character.

* Source/WebKit/UIProcess/API/APIContentRuleListStore.cpp:
(API::getContentRuleListSourceFromMappedFile): Cast to Latin1Character.

* Source/WebKit/UIProcess/API/C/WKPage.cpp:
(dataFrom): Cast to uint8_t.

* Source/WebKit/UIProcess/Cocoa/WebPasteboardProxyCocoa.mm:
(WebKit::WebPasteboardProxy::testIPCSharedMemory): Cast to Latin1Character.
* Source/WebKit/UIProcess/Extensions/WebExtensionDeclarativeNetRequestSQLiteStore.cpp:
(WebKit::WebExtensionDeclarativeNetRequestSQLiteStore::getKeysAndValuesFromRowIterator):
Ditto.

* Source/WebKit/UIProcess/Inspector/glib/RemoteInspectorClient.cpp:
(WebKit::RemoteInspectorClient::setBackendCommands): Cast to std::byte.

* Source/WebKit/UIProcess/Inspector/mac/RemoteWebInspectorUIProxyMac.mm:
(WebKit::RemoteWebInspectorUIProxy::platformLoad): Cast to Latin1Character.
* Source/WebKit/UIProcess/Inspector/mac/WebInspectorUIProxyMac.mm:
(WebKit::WebInspectorUIProxy::platformLoad): Ditto.
* Source/WebKit/UIProcess/wpe/WebPasteboardProxyWPE.cpp:
(WebKit::WebPasteboardProxy::readURLFromPasteboard): Ditto.
* Source/WebKit/WebProcess/Network/webrtc/RTCDataChannelRemoteManager.cpp:
(WebKit::RTCDataChannelRemoteManager::sendData): Ditto.

* Source/WebKit/WebProcess/cocoa/WebProcessCocoa.mm:
(WebKit::registerLogClient): Cast to uint8_t.

* Tools/TestWebKitAPI/Tests/WTF/Base64.cpp:
(TestWebKitAPI::TEST(Base64, Encode)): Cast to uint8_t.
(TestWebKitAPI::TEST(Base64, EncodeOmitPadding)): Ditto.
(TestWebKitAPI::TEST(Base64, EncodeURL)): Ditto.
(TestWebKitAPI::TEST(Base64, EncodeURLOmitPadding)): Ditto.
* Tools/TestWebKitAPI/Tests/WTF/FileSystem.cpp:
(TestWebKitAPI::createTestFile): Ditto.
(TestWebKitAPI::TEST_F(FileSystemTest, openExistingFileTruncate)): Ditto.
(TestWebKitAPI::TEST_F(FileSystemTest, openExistingFileReadWrite)): Ditto.
(TestWebKitAPI::TEST_F(FileSystemTest, deleteEmptyDirectoryContainingDSStoreFile)): Ditto.
(TestWebKitAPI::TEST_F(FileSystemTest, deleteEmptyDirectoryOnNonEmptyDirectory)): Ditto.
(TestWebKitAPI::TEST_F(FileSystemTest, moveDirectory)): Ditto.
(TestWebKitAPI::runGetFileModificationTimeTest): Ditto.
(TestWebKitAPI::TEST_F(FileSystemTest, readEntireFile)): Ditto.

* Tools/TestWebKitAPI/Tests/WTF/StringImpl.cpp:
(TestWebKitAPI::TEST(WTF, ExternalStringImplCreate8bit)): Use char and cast to Latin1Character.
(TestWebKitAPI::TEST(WTF, ExternalStringAtom)): Ditto.

* Tools/TestWebKitAPI/Tests/WTF/StringView.cpp:
(TestWebKitAPI::TEST(WTF, StringViewEqualIgnoringASCIICaseWithLatin1Characters)):
Use byteCast instead of reinterpret_cast.

* Tools/TestWebKitAPI/Tests/WTF/cocoa/URLExtras.mm:
(TestWebKitAPI::dataAsString): Pass a character instead of an int.

* Tools/TestWebKitAPI/Tests/WebCore/PushMessageCrypto.cpp:
(TestWebKitAPI::mustBase64URLDecode): Use ASCIILiteral.
(TestWebKitAPI::stringView): Added.
(TestWebKitAPI::TEST(PushMessageCrypto, AES128GCMPayloadWithMinimalPadding)): Use stringView.
(TestWebKitAPI::TEST(PushMessageCrypto, AES128GCMPayloadWithPadding)): Ditto.
(TestWebKitAPI::TEST(PushMessageCrypto, AESGCMPayloadWithMinimalPadding)): Ditto.
(TestWebKitAPI::TEST(PushMessageCrypto, AESGCMPayloadWithPadding)): Ditto.

* Tools/TestWebKitAPI/Tests/WebCore/SharedBuffer.cpp:
(TestWebKitAPI::TEST_F(FragmentedSharedBufferTest, createWithContentsOfExistingFile)):
Cast to Latin1Character.
(TestWebKitAPI::TEST_F(FragmentedSharedBufferTest, read)): Ditto.
(TestWebKitAPI::TEST_F(SharedBufferChunkReaderTest, includeSeparator)): Use uint8_t.
(TestWebKitAPI::TEST_F(SharedBufferChunkReaderTest, peekData)): Cast to Latin1Character.

* Tools/TestWebKitAPI/Tests/WebCore/SharedBufferTest.cpp:
(TestWebKitAPI::FragmentedSharedBufferTest::SetUp): Cast to uint8_t.
* Tools/TestWebKitAPI/Tests/WebCore/curl/CurlMultipartHandleTests.cpp:
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, SimpleMessage)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, NoHeader)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, NoBody)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, TransportPadding)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, NoEndOfBoundary)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, NoEndOfBoundaryAfterCompleted)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, NoCloseDelimiter)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, NoCloseDelimiterAfterCompleted)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, CloseDelimiter)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, CloseDelimiterAfterCompleted)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideFirstDelimiter)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideSecondDelimiter)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideLastDelimiter)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideCloseDelimiter)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideTransportPadding)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideHeader)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, DivideBody)): Ditto.
(TestWebKitAPI::Curl::TEST(CurlMultipartHandleTests, CompleteWhileHeaderProcessing)): Ditto.
* Tools/TestWebKitAPI/Tests/WebKitCocoa/IndexedDBPersistence.mm:
(-[IndexedDBOpenPanelUIDelegate webView:runOpenPanelWithParameters:initiatedByFrame:completionHandler:]): Ditto.

* Tools/TestWebKitAPI/Tests/WebKitCocoa/WebPushDaemon.mm:
(TestWebKitAPI::WebPushDTestWebView::injectPushMessage): Cast to Latin1Character.

Canonical link: https://commits.webkit.org/301031@main

Signed-off-by: Xabier Rodriguez Calvar <calvaris@igalia.com>

Author: darinadler

Source/JavaScriptCore/API/JSScript.mm

@@ -146,7 +146,7 @@ + (instancetype)scriptOfType:(JSScriptType)type memoryMappedFromASCIIFile:(NSURL
     auto result = adoptNS([[JSScript alloc] init]);
     result->m_virtualMachine = vm;
     result->m_type = type;
-    result->m_source = String(StringImpl::createWithoutCopying(fileData.span()));
+    result->m_source = StringImpl::createWithoutCopying(byteCast<Latin1Character>(fileData.span()));
     result->m_mappedSource = WTFMove(fileData);
     result->m_sourceURL = sourceURL;
     result->m_cachePath = cachePath;

Source/JavaScriptCore/API/JSStringRefCF.cpp

@@ -47,7 +47,7 @@ JSStringRef JSStringCreateWithCFString(CFStringRef string)
 
     Vector<Latin1Character, 1024> lcharBuffer(length);
     CFIndex usedBufferLength;
-    CFIndex convertedSize = CFStringGetBytes(string, CFRangeMake(0, length), kCFStringEncodingISOLatin1, 0, false, lcharBuffer.data(), length, &usedBufferLength);
+    CFIndex convertedSize = CFStringGetBytes(string, CFRangeMake(0, length), kCFStringEncodingISOLatin1, 0, false, byteCast<UInt8>(lcharBuffer.data()), length, &usedBufferLength);
     if (static_cast<size_t>(convertedSize) == length && static_cast<size_t>(usedBufferLength) == length)
         return &OpaqueJSString::create(lcharBuffer.span()).leakRef();
 
@@ -64,7 +64,7 @@ CFStringRef JSStringCopyCFString(CFAllocatorRef allocator, JSStringRef string)
 
     if (string->is8Bit()) {
         auto characters = string->span8();
-        return CFStringCreateWithBytes(allocator, characters.data(), characters.size(), kCFStringEncodingISOLatin1, false);
+        return CFStringCreateWithBytes(allocator, byteCast<UInt8>(characters.data()), characters.size(), kCFStringEncodingISOLatin1, false);
     }
     auto characters = string->span16();
     return CFStringCreateWithCharacters(allocator, reinterpret_cast<const UniChar*>(characters.data()), characters.size());

Source/JavaScriptCore/inspector/remote/socket/RemoteInspectorSocket.cpp

@@ -262,7 +262,7 @@ String RemoteInspector::backendCommands() const
 
     auto contents = FileSystem::readEntireFile(m_backendCommandsPath);
 
-    return contents ? String::adopt(WTFMove(*contents)) : emptyString();
+    return contents ? String { byteCast<Latin1Character>(contents->span()) } : emptyString();
 }
 
 // RemoteInspectorConnectionClient handlers

Source/JavaScriptCore/runtime/JSGenericTypedArrayViewPrototype.cpp

@@ -233,7 +233,6 @@ JSC_DEFINE_HOST_FUNCTION(uint8ArrayPrototypeToHex, (JSGlobalObject* globalObject
 
     std::span<Latin1Character> buffer;
     auto result = StringImpl::createUninitialized(length * 2, buffer);
-    Latin1Character* bufferEnd = std::to_address(buffer.end());
     constexpr size_t stride = 8; // Because loading uint8x8_t.
     if (length >= stride) {
         auto encodeVector = [&](auto input) {
@@ -259,11 +258,10 @@ JSC_DEFINE_HOST_FUNCTION(uint8ArrayPrototypeToHex, (JSGlobalObject* globalObject
         };
 
         const auto* cursor = data;
-        auto* output = buffer.data();
-        for (; cursor + stride <= end; cursor += stride, output += stride * 2)
+        for (auto* output = byteCast<uint8_t>(buffer.data()); cursor + stride <= end; cursor += stride, output += stride * 2)
             simde_vst1q_u8(output, encodeVector(simde_vld1_u8(cursor)));
         if (cursor < end)
-            simde_vst1q_u8(bufferEnd - stride * 2, encodeVector(simde_vld1_u8(end - stride)));
+            simde_vst1q_u8(byteCast<uint8_t>(std::to_address(buffer.end())) - stride * 2, encodeVector(simde_vld1_u8(end - stride)));
     } else {
         const auto* cursor = data;
         auto* output = buffer.data();

Source/JavaScriptCore/runtime/LiteralParser.cpp

@@ -911,7 +911,7 @@ ALWAYS_INLINE TokenType LiteralParser<CharType, reviverMode>::Lexer::lexString(L
     if (m_mode == StrictJSON) {
         ASSERT(terminator == '"');
         if constexpr (hint == JSONIdentifierHint::MaybeIdentifier) {
-            while (m_ptr < m_end && isSafeStringCharacterForIdentifier<SafeStringCharacterSet::Strict>(*m_ptr, '"'))
+            while (m_ptr < m_end && isSafeStringCharacterForIdentifier<SafeStringCharacterSet::Strict>(*m_ptr, terminator))
                 ++m_ptr;
         } else {
             using UnsignedType = std::make_unsigned_t<CharType>;
@@ -926,8 +926,8 @@ ALWAYS_INLINE TokenType LiteralParser<CharType, reviverMode>::Lexer::lexString(L
                 return SIMD::findFirstNonZeroIndex(mask);
             };
 
-            auto scalarMatch = [&](auto character) ALWAYS_INLINE_LAMBDA {
-                return !isSafeStringCharacter<SafeStringCharacterSet::Strict>(character, '"');
+            auto scalarMatch = [&](CharType character) ALWAYS_INLINE_LAMBDA {
+                return !isSafeStringCharacter<SafeStringCharacterSet::Strict>(character, terminator);
             };
 
             m_ptr = SIMD::find(std::span { m_ptr, m_end }, vectorMatch, scalarMatch);

Source/WTF/wtf/cf/CFURLExtras.cpp

@@ -56,7 +56,7 @@ String bytesAsString(CFURLRef url)
     RELEASE_ASSERT(bytesLength <= static_cast<CFIndex>(String::MaxLength));
     Latin1Character* buffer;
     auto result = String::createUninitialized(bytesLength, buffer);
-    CFURLGetBytes(url, buffer, bytesLength);
+    CFURLGetBytes(url, byteCast<UInt8>(buffer()), bytesLength);
     return result;
 }
 
@@ -90,7 +90,7 @@ bool isSameOrigin(CFURLRef a, const URL& b)
     auto aBytes = bytesAsVector(a);
     RELEASE_ASSERT(aBytes.size() <= String::MaxLength);
 
-    StringView aString { aBytes.span() };
+    StringView aString { byteCast<Latin1Character>(aBytes.span()) };
     StringView bString { b.string() };
 
     if (!b.hasPath())

Source/WTF/wtf/cocoa/NSURLExtras.mm

@@ -317,7 +317,7 @@ static bool hasQuestionMarkOnlyQueryString(NSURL *URL)
 
 NSString *userVisibleString(NSURL *URL)
 {
-    return URLHelpers::userVisibleURL(span(originalURLData(URL)));
+    return URLHelpers::userVisibleURL(byteCast<Latin1Character>(span(originalURLData(URL))));
 }
 
 BOOL isUserVisibleURL(NSString *string)

Source/WTF/wtf/persistence/PersistentCoders.cpp

@@ -100,7 +100,7 @@ void Coder<String>::encodeForPersistence(Encoder& encoder, const String& string)
     encoder << string.length() << is8Bit;
 
     if (is8Bit)
-        encoder.encodeFixedLengthData(string.span8());
+        encoder.encodeFixedLengthData(asBytes(string.span8()));
     else
         encoder.encodeFixedLengthData(asBytes(string.span16()));
 }

Source/WTF/wtf/text/StringBuilder.h

@@ -278,8 +278,7 @@ inline unsigned StringBuilder::capacity() const
 
 inline char16_t StringBuilder::operator[](unsigned i) const
 {
-    RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(i < length());
-    return is8Bit() ? characters<Latin1Character>()[i] : characters<char16_t>()[i];
+    return is8Bit() ? char16_t { span8()[i] } : span16()[i];
 }
 
 inline bool StringBuilder::is8Bit() const

Source/WTF/wtf/text/WTFString.cpp

@@ -51,8 +51,9 @@ String::String(std::span<const Latin1Character> characters)
 {
 }
 
+// Construct a string with Latin-1 data.
 String::String(std::span<const char> characters)
-    : m_impl(characters.data() ? RefPtr { StringImpl::create(byteCast<uint8_t>(characters)) } : nullptr)
+    : m_impl(characters.data() ? RefPtr { StringImpl::create(byteCast<Latin1Character>(characters)) } : nullptr)
 {
 }
 
@@ -392,9 +393,9 @@ CString String::ascii() const
         CString result = CString::newUninitialized(characters.size(), characterBuffer);
 
         for (auto character : characters)
-            *characterBuffer++ = character && (character < 0x20 || character > 0x7f) ? '?' : character;
+            *characterBuffer++ = character && (character < 0x20 || character > 0x7f) ? '?' : byteCast<char>(character);
 
-        return result;        
+        return result;
     }
 
     auto characters = span16();