diff --git a/BUILD.gn b/BUILD.gn
index 1603e2b0ec7..02819d0e4e8 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -108,7 +108,6 @@ group("dart2wasm_platform") {
     ":runtime_precompiled",
     "utils/dart2wasm:compile_dart2wasm_js_compatibility_platform",
     "utils/dart2wasm:compile_dart2wasm_platform",
-    "utils/dart2wasm:compile_dart2wasm_stringref_platform",
     "utils/dart2wasm:dart2wasm_snapshot",
   ]
   if (defined(is_product)) {
diff --git a/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart b/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
index 846274fbc45..c3f149849f7 100644
--- a/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
@@ -4743,7 +4743,7 @@ const MessageCode messageFastaUsageLong =
     Read the SDK platform from <file>, which should be in Dill/Kernel IR format
     and contain the Dart SDK.
 
-  --target=dart2js|dart2js_server|dart2wasm|dart2wasm_js_compatibility|dart2wasm_stringref|dart_runner|dartdevc|flutter|flutter_runner|none|vm
+  --target=dart2js|dart2js_server|dart2wasm|dart2wasm_js_compatibility|dart_runner|dartdevc|flutter|flutter_runner|none|vm
     Specify the target configuration.
 
   --enable-asserts
diff --git a/pkg/dart2wasm/README.md b/pkg/dart2wasm/README.md
index 26bf0728ed5..616ebb346cf 100644
--- a/pkg/dart2wasm/README.md
+++ b/pkg/dart2wasm/README.md
@@ -37,7 +37,6 @@ where *options* include:
 | `--`[`no-`]`polymorphic-specialization` | no      | Do virtual calls by switching on the class ID instead of using `call_indirect`.
 | `--`[`no-`]`print-kernel`               | no      | Print IR for each function before compiling it.
 | `--`[`no-`]`print-wasm`                 | no      | Print Wasm instructions of each compiled function.
-| `--`[`no-`]`stringref`                  | no      | Use the experimental stringref Wasm proposal.
 | `--`[`no-`]`enable-asserts`             | no      | Enable assertions at runtime.
 | `--`[`no-`]`js-compatibility`           | no      | Enable JS compatibility mode.
 | `--shared-memory-max-pages` *pagecount* |         | Max size of the imported memory buffer. If `--shared-import-memory` is specified, this must also be specified.
diff --git a/pkg/dart2wasm/lib/compile.dart b/pkg/dart2wasm/lib/compile.dart
index e642e1290a1..ea9c6b62b3e 100644
--- a/pkg/dart2wasm/lib/compile.dart
+++ b/pkg/dart2wasm/lib/compile.dart
@@ -69,9 +69,7 @@ Future<CompilerOutput?> compileToModule(compiler.CompilerOptions options,
   }
 
   final wasm.Mode mode;
-  if (options.translatorOptions.useStringref) {
-    mode = wasm.Mode.stringref;
-  } else if (options.translatorOptions.jsCompatibility) {
+  if (options.translatorOptions.jsCompatibility) {
     mode = wasm.Mode.jsCompatibility;
   } else {
     mode = wasm.Mode.regular;
diff --git a/pkg/dart2wasm/lib/dart2wasm.dart b/pkg/dart2wasm/lib/dart2wasm.dart
index 4ae5db164ca..32b84818874 100644
--- a/pkg/dart2wasm/lib/dart2wasm.dart
+++ b/pkg/dart2wasm/lib/dart2wasm.dart
@@ -34,8 +34,6 @@ final List<Option> options = [
       defaultsTo: _d.translatorOptions.printKernel),
   Flag("print-wasm", (o, value) => o.translatorOptions.printWasm = value,
       defaultsTo: _d.translatorOptions.printWasm),
-  Flag("stringref", (o, value) => o.translatorOptions.useStringref = value,
-      defaultsTo: _d.translatorOptions.useStringref),
   Flag("js-compatibility",
       (o, value) => o.translatorOptions.jsCompatibility = value,
       defaultsTo: _d.translatorOptions.jsCompatibility),
diff --git a/pkg/dart2wasm/lib/target.dart b/pkg/dart2wasm/lib/target.dart
index a0a79446032..ff4aec70d1e 100644
--- a/pkg/dart2wasm/lib/target.dart
+++ b/pkg/dart2wasm/lib/target.dart
@@ -36,7 +36,6 @@ import 'package:dart2wasm/transformers.dart' as wasmTrans;
 
 enum Mode {
   regular,
-  stringref,
   jsCompatibility,
 }
 
@@ -122,8 +121,6 @@ class WasmTarget extends Target {
     switch (mode) {
       case Mode.regular:
         return 'wasm';
-      case Mode.stringref:
-        return 'wasm_stringref';
       case Mode.jsCompatibility:
         return 'wasm_js_compatibility';
     }
@@ -133,8 +130,6 @@ class WasmTarget extends Target {
     switch (mode) {
       case Mode.regular:
         return 'dart2wasm_platform.dill';
-      case Mode.stringref:
-        return 'dart2wasm_stringref_platform.dill';
       case Mode.jsCompatibility:
         return 'dart2wasm_js_compatibility_platform.dill';
     }
diff --git a/pkg/front_end/lib/src/compute_platform_binaries_location.dart b/pkg/front_end/lib/src/compute_platform_binaries_location.dart
index 012c9f74d9c..c8528f83066 100644
--- a/pkg/front_end/lib/src/compute_platform_binaries_location.dart
+++ b/pkg/front_end/lib/src/compute_platform_binaries_location.dart
@@ -75,17 +75,6 @@ String? computePlatformDillName(
           break;
       }
       break;
-    case 'wasm_stringref':
-      switch (nnbdMode) {
-        case NnbdMode.Strong:
-          return 'dart2wasm_stringref_outline.dill';
-        //TODO(johnniwinther): Support using the full dill.
-        //return 'dart2wasm_stringref_platform.dill';
-        case NnbdMode.Weak:
-        case NnbdMode.Agnostic:
-          break;
-      }
-      break;
     case 'wasm_js_compatibility':
       switch (nnbdMode) {
         case NnbdMode.Strong:
diff --git a/pkg/front_end/messages.yaml b/pkg/front_end/messages.yaml
index 1df27217ec2..02c3012a83e 100644
--- a/pkg/front_end/messages.yaml
+++ b/pkg/front_end/messages.yaml
@@ -2359,7 +2359,7 @@ FastaUsageLong:
         Read the SDK platform from <file>, which should be in Dill/Kernel IR format
         and contain the Dart SDK.
 
-      --target=dart2js|dart2js_server|dart2wasm|dart2wasm_js_compatibility|dart2wasm_stringref|dart_runner|dartdevc|flutter|flutter_runner|none|vm
+      --target=dart2js|dart2js_server|dart2wasm|dart2wasm_js_compatibility|dart_runner|dartdevc|flutter|flutter_runner|none|vm
         Specify the target configuration.
 
       --enable-asserts
diff --git a/pkg/front_end/test/spell_checking_list_common.txt b/pkg/front_end/test/spell_checking_list_common.txt
index da8223ffb38..75007233166 100644
--- a/pkg/front_end/test/spell_checking_list_common.txt
+++ b/pkg/front_end/test/spell_checking_list_common.txt
@@ -739,7 +739,6 @@ dart
 dart2js
 dart2wasm
 dart2wasm_js_compatibility
-dart2wasm_stringref
 dartdevc
 data
 date
@@ -2929,7 +2928,6 @@ stray
 stream
 strictly
 string
-stringref
 strings
 stripped
 strong
diff --git a/pkg/front_end/tool/_fasta/additional_targets.dart b/pkg/front_end/tool/_fasta/additional_targets.dart
index 01a77853894..d389ff7eff4 100644
--- a/pkg/front_end/tool/_fasta/additional_targets.dart
+++ b/pkg/front_end/tool/_fasta/additional_targets.dart
@@ -26,8 +26,6 @@ void installAdditionalTargets() {
       (TargetFlags flags) => new Dart2jsTarget("dart2js_server", flags);
   targets["dartdevc"] = (TargetFlags flags) => new DevCompilerTarget(flags);
   targets["dart2wasm"] = (TargetFlags flags) => new WasmTarget();
-  targets["dart2wasm_stringref"] =
-      (TargetFlags flags) => new WasmTarget(mode: wasm.Mode.stringref);
   targets["dart2wasm_js_compatibility"] =
       (TargetFlags flags) => new WasmTarget(mode: wasm.Mode.jsCompatibility);
   vm_target_install.installAdditionalTargets();
diff --git a/sdk/BUILD.gn b/sdk/BUILD.gn
index e8ab581e248..36add6138c1 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -69,8 +69,6 @@ declare_args() {
 # ........dart2js_server_platform_unsound.dill
 # ........dart2wasm_outline.dill (if not on ia32)
 # ........dart2wasm_platform.dill (if not on ia32)
-# ........dart2wasm_stringref_outline.dill (if not on ia32)
-# ........dart2wasm_stringref_platform.dill (if not on ia32)
 # ........dart2wasm_js_compatibility_outline.dill (if not on ia32)
 # ........dart2wasm_js_compatibility_platform.dill (if not on ia32)
 # ........ddc_outline.dill
@@ -524,15 +522,12 @@ copy("copy_dart2wasm_platform") {
     "../:dart2wasm_platform",
     "../utils/dart2wasm:compile_dart2wasm_js_compatibility_platform",
     "../utils/dart2wasm:compile_dart2wasm_platform",
-    "../utils/dart2wasm:compile_dart2wasm_stringref_platform",
   ]
   sources = [
     "$root_out_dir/dart2wasm_js_compatibility_outline.dill",
     "$root_out_dir/dart2wasm_js_compatibility_platform.dill",
     "$root_out_dir/dart2wasm_outline.dill",
     "$root_out_dir/dart2wasm_platform.dill",
-    "$root_out_dir/dart2wasm_stringref_outline.dill",
-    "$root_out_dir/dart2wasm_stringref_platform.dill",
   ]
   outputs =
       [ "$root_out_dir/$dart_sdk_output/lib/_internal/{{source_file_part}}" ]
diff --git a/sdk/bin/dart2wasm b/sdk/bin/dart2wasm
index 8615c9e497c..f6d20d0d6e3 100755
--- a/sdk/bin/dart2wasm
+++ b/sdk/bin/dart2wasm
@@ -95,9 +95,6 @@ fi
 # Not the prettiest way to check for a target, and it doesn't support changing
 # the default, but it will do for experiments.
 for arg in "${ARGS[@]}"; do
-  if [[ "$arg" == "--stringref" ]]; then
-    PLATFORM="$BIN_DIR/dart2wasm_stringref_platform.dill"
-  fi
   if [[ "$arg" == "--js-compatibility" ]]; then
     PLATFORM="$BIN_DIR/dart2wasm_js_compatibility_platform.dill"
   fi
diff --git a/sdk/lib/_internal/wasm/lib/string_stringref_patch.dart b/sdk/lib/_internal/wasm/lib/string_stringref_patch.dart
deleted file mode 100644
index 80a506f138c..00000000000
--- a/sdk/lib/_internal/wasm/lib/string_stringref_patch.dart
+++ /dev/null
@@ -1,1476 +0,0 @@
-// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// TODO: Implementation of strings for the stringref target.
-// For now, this file is identical to string_patch.dart.
-// When we implement the stringref strings here, we'll likely also need to
-// restructure some other patch files to make code dependent on the string
-// implementation live in separate patch files for the two targets.
-
-import "dart:_internal"
-    show
-        CodeUnits,
-        ClassID,
-        doubleToIntBits,
-        EfficientLengthIterable,
-        intBitsToDouble,
-        IterableElementError,
-        jsonEncode,
-        Lists,
-        mix64,
-        makeListFixedLength,
-        patch,
-        unsafeCast,
-        writeIntoOneByteString,
-        writeIntoTwoByteString;
-
-import 'dart:_js_helper' show JS;
-import 'dart:_js_types' show JSStringImpl;
-import 'dart:_object_helper';
-import 'dart:_string_helper';
-import 'dart:_wasm';
-
-import "dart:typed_data" show Uint8List, Uint16List;
-
-const int _maxAscii = 0x7f;
-const int _maxLatin1 = 0xff;
-const int _maxUtf16 = 0xffff;
-const int _maxUnicode = 0x10ffff;
-
-/// The [fromStart] and [toStart] indices together with the [length] must
-/// specify ranges within the bounds of the list / string.
-void _copyRangeFromUint8ListToOneByteString(
-    Uint8List from, _OneByteString to, int fromStart, int toStart, int length) {
-  for (int i = 0; i < length; i++) {
-    to._setAt(toStart + i, from[fromStart + i]);
-  }
-}
-
-String _toUpperCase(String string) => JS<String>(
-    "s => stringToDartString(stringFromDartString(s).toUpperCase())", string);
-
-String _toLowerCase(String string) => JS<String>(
-    "s => stringToDartString(stringFromDartString(s).toLowerCase())", string);
-
-@patch
-class String {
-  @patch
-  factory String.fromCharCodes(Iterable<int> charCodes,
-      [int start = 0, int? end]) {
-    return _StringBase.createFromCharCodes(charCodes, start, end, null);
-  }
-
-  @patch
-  factory String.fromCharCode(int charCode) {
-    if (charCode >= 0) {
-      if (charCode <= 0xff) {
-        return _OneByteString._allocate(1).._setAt(0, charCode);
-      }
-      if (charCode <= 0xffff) {
-        return _TwoByteString._allocate(1).._setAt(0, charCode);
-      }
-      if (charCode <= 0x10ffff) {
-        int low = 0xDC00 | (charCode & 0x3ff);
-        int bits = charCode - 0x10000;
-        int high = 0xD800 | (bits >> 10);
-        return _TwoByteString._allocate(2)
-          .._setAt(0, high)
-          .._setAt(1, low);
-      }
-    }
-    throw new RangeError.range(charCode, 0, 0x10ffff);
-  }
-
-  @patch
-  external const factory String.fromEnvironment(String name,
-      {String defaultValue = ""});
-}
-
-extension _StringExtension on String {
-  bool get _isOneByte => this is _OneByteString;
-}
-
-/**
- * [_StringBase] contains common methods used by concrete String
- * implementations, e.g., _OneByteString.
- */
-abstract final class _StringBase implements String {
-  bool _isWhitespace(int codeUnit);
-
-  // Constants used by replaceAll encoding of string slices between matches.
-  // A string slice (start+length) is encoded in a single Smi to save memory
-  // overhead in the common case.
-  // We use fewer bits for length (11 bits) than for the start index (19+ bits).
-  // For long strings, it's possible to have many large indices,
-  // but it's unlikely to have many long lengths since slices don't overlap.
-  // If there are few matches in a long string, then there are few long slices,
-  // and if there are many matches, there'll likely be many short slices.
-  //
-  // Encoding is: 0((start << _lengthBits) | length)
-
-  // Number of bits used by length.
-  // This is the shift used to encode and decode the start index.
-  static const int _lengthBits = 11;
-  // The maximal allowed length value in an encoded slice.
-  static const int _maxLengthValue = (1 << _lengthBits) - 1;
-  // Mask of length in encoded smi value.
-  static const int _lengthMask = _maxLengthValue;
-  static const int _startBits = _maxUnsignedSmiBits - _lengthBits;
-  // Maximal allowed start index value in an encoded slice.
-  static const int _maxStartValue = (1 << _startBits) - 1;
-  // We pick 30 as a safe lower bound on available bits in a negative smi.
-  // TODO(lrn): Consider allowing more bits for start on 64-bit systems.
-  static const int _maxUnsignedSmiBits = 30;
-
-  // For longer strings, calling into C++ to create the result of a
-  // [replaceAll] is faster than [_joinReplaceAllOneByteResult].
-  // TODO(lrn): See if this limit can be tweaked.
-  static const int _maxJoinReplaceOneByteStringLength = 500;
-
-  _StringBase._();
-
-  int get hashCode {
-    int hash = getHash(this);
-    if (hash != 0) return hash;
-    hash = _computeHashCode();
-    setHash(this, hash);
-    return hash;
-  }
-
-  int _computeHashCode();
-
-  /**
-   * Create the most efficient string representation for specified
-   * [charCodes].
-   *
-   * Only uses the character codes between index [start] and index [end] of
-   * `charCodes`. They must satisfy `0 <= start <= end <= charCodes.length`.
-   *
-   * The [limit] is an upper limit on the character codes in the iterable.
-   * It's `null` if unknown.
-   */
-  static String createFromCharCodes(
-      Iterable<int> charCodes, int start, int? end, int? limit) {
-    // TODO(srdjan): Also skip copying of wide typed arrays.
-    final ccid = ClassID.getID(charCodes);
-    if (ccid != ClassID.cidFixedLengthList &&
-        ccid != ClassID.cidListBase &&
-        ccid != ClassID.cidGrowableList &&
-        ccid != ClassID.cidImmutableList) {
-      if (charCodes is Uint8List) {
-        final actualEnd =
-            RangeError.checkValidRange(start, end, charCodes.length);
-        return _createOneByteString(charCodes, start, actualEnd - start);
-      } else if (charCodes is! Uint16List) {
-        return _createStringFromIterable(charCodes, start, end);
-      }
-    }
-    final int codeCount = charCodes.length;
-    final actualEnd = RangeError.checkValidRange(start, end, codeCount);
-    final len = actualEnd - start;
-    if (len == 0) return "";
-
-    final typedCharCodes = unsafeCast<List<int>>(charCodes);
-
-    final int actualLimit =
-        limit ?? _scanCodeUnits(typedCharCodes, start, actualEnd);
-    if (actualLimit < 0) {
-      throw new ArgumentError(typedCharCodes);
-    }
-    if (actualLimit <= _maxLatin1) {
-      return _createOneByteString(typedCharCodes, start, len);
-    }
-    if (actualLimit <= _maxUtf16) {
-      return _TwoByteString._allocateFromTwoByteList(
-          typedCharCodes, start, actualEnd);
-    }
-    // TODO(lrn): Consider passing limit to _createFromCodePoints, because
-    // the function is currently fully generic and doesn't know that its
-    // charCodes are not all Latin-1 or Utf-16.
-    return _createFromCodePoints(typedCharCodes, start, actualEnd);
-  }
-
-  static int _scanCodeUnits(List<int> charCodes, int start, int end) {
-    int bits = 0;
-    for (int i = start; i < end; i++) {
-      int code = charCodes[i];
-      bits |= code;
-    }
-    return bits;
-  }
-
-  static String _createStringFromIterable(
-      Iterable<int> charCodes, int start, int? end) {
-    // Treat charCodes as Iterable.
-    if (charCodes is EfficientLengthIterable) {
-      int length = charCodes.length;
-      final endVal = RangeError.checkValidRange(start, end, length);
-      final charCodeList =
-          List<int>.from(charCodes.take(endVal).skip(start), growable: false);
-      return createFromCharCodes(charCodeList, 0, charCodeList.length, null);
-    }
-    // Don't know length of iterable, so iterate and see if all the values
-    // are there.
-    if (start < 0) throw new RangeError.range(start, 0, charCodes.length);
-    var it = charCodes.iterator;
-    for (int i = 0; i < start; i++) {
-      if (!it.moveNext()) {
-        throw new RangeError.range(start, 0, i);
-      }
-    }
-    List<int> charCodeList;
-    int bits = 0; // Bitwise-or of all char codes in list.
-    final endVal = end;
-    if (endVal == null) {
-      var list = <int>[];
-      while (it.moveNext()) {
-        int code = it.current;
-        bits |= code;
-        list.add(code);
-      }
-      charCodeList = makeListFixedLength<int>(list);
-    } else {
-      if (endVal < start) {
-        throw new RangeError.range(endVal, start, charCodes.length);
-      }
-      int len = endVal - start;
-      charCodeList = new List<int>.generate(len, (int i) {
-        if (!it.moveNext()) {
-          throw new RangeError.range(endVal, start, start + i);
-        }
-        int code = it.current;
-        bits |= code;
-        return code;
-      });
-    }
-    int length = charCodeList.length;
-    if (bits < 0) {
-      throw new ArgumentError(charCodes);
-    }
-    bool isOneByteString = (bits <= _maxLatin1);
-    if (isOneByteString) {
-      return _createOneByteString(charCodeList, 0, length);
-    }
-    return createFromCharCodes(charCodeList, 0, length, bits);
-  }
-
-  // Inlining is disabled as a workaround to http://dartbug.com/37800.
-
-  static String _createOneByteString(List<int> charCodes, int start, int len) {
-    // It's always faster to do this in Dart than to call into the runtime.
-    var s = _OneByteString._allocate(len);
-
-    // Special case for native Uint8 typed arrays.
-    if (charCodes is Uint8List) {
-      _copyRangeFromUint8ListToOneByteString(charCodes, s, start, 0, len);
-      return s;
-    }
-
-    // Fall through to normal case.
-    for (int i = 0; i < len; i++) {
-      s._setAt(i, charCodes[start + i]);
-    }
-    return s;
-  }
-
-  static String _createFromOneByteCodes(
-      List<int> charCodes, int start, int end) {
-    _OneByteString result = _OneByteString._allocate(end - start);
-    for (int i = start; i < end; i++) {
-      result._setAt(i - start, charCodes[i]);
-    }
-    return result;
-  }
-
-  static String _createFromCodePoints(List<int> charCodes, int start, int end) {
-    for (int i = start; i < end; i++) {
-      int c = charCodes[i];
-      if (c < 0) throw ArgumentError.value(i);
-      if (c > 0xff) {
-        return _createFromAdjustedCodePoints(charCodes, start, end);
-      }
-    }
-    return _createFromOneByteCodes(charCodes, start, end);
-  }
-
-  static String _createFromAdjustedCodePoints(
-      List<int> codePoints, int start, int end) {
-    StringBuffer a = StringBuffer();
-    for (int i = start; i < end; i++) {
-      a.writeCharCode(codePoints[i]);
-    }
-    return a.toString();
-  }
-
-  String operator [](int index) => String.fromCharCode(codeUnitAt(index));
-
-  int codeUnitAt(int index); // Implemented in the subclasses.
-
-  int get length; // Implemented in the subclasses.
-
-  bool get isEmpty {
-    return this.length == 0;
-  }
-
-  bool get isNotEmpty => !isEmpty;
-
-  String operator +(String other) => _interpolate([this, other]);
-
-  String toString() {
-    return this;
-  }
-
-  bool operator ==(Object other) {
-    if (identical(this, other)) {
-      return true;
-    }
-    if (other is String && this.length == other.length) {
-      final len = this.length;
-      for (int i = 0; i < len; i++) {
-        if (this.codeUnitAt(i) != other.codeUnitAt(i)) {
-          return false;
-        }
-      }
-      return true;
-    }
-    return false;
-  }
-
-  int compareTo(String other) {
-    int thisLength = this.length;
-    int otherLength = other.length;
-    int len = (thisLength < otherLength) ? thisLength : otherLength;
-    for (int i = 0; i < len; i++) {
-      int thisCodeUnit = this.codeUnitAt(i);
-      int otherCodeUnit = other.codeUnitAt(i);
-      if (thisCodeUnit < otherCodeUnit) {
-        return -1;
-      }
-      if (thisCodeUnit > otherCodeUnit) {
-        return 1;
-      }
-    }
-    if (thisLength < otherLength) return -1;
-    if (thisLength > otherLength) return 1;
-    return 0;
-  }
-
-  bool _substringMatches(int start, String other) {
-    if (other.isEmpty) return true;
-    final len = other.length;
-    if ((start < 0) || (start + len > this.length)) {
-      return false;
-    }
-    for (int i = 0; i < len; i++) {
-      if (this.codeUnitAt(i + start) != other.codeUnitAt(i)) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  bool endsWith(String other) {
-    return _substringMatches(this.length - other.length, other);
-  }
-
-  bool startsWith(Pattern pattern, [int index = 0]) {
-    if ((index < 0) || (index > this.length)) {
-      throw new RangeError.range(index, 0, this.length);
-    }
-    if (pattern is String) {
-      return _substringMatches(index, pattern);
-    }
-    return pattern.matchAsPrefix(this, index) != null;
-  }
-
-  int indexOf(Pattern pattern, [int start = 0]) {
-    if ((start < 0) || (start > this.length)) {
-      throw new RangeError.range(start, 0, this.length, "start");
-    }
-    if (pattern is String) {
-      String other = pattern;
-      int maxIndex = this.length - other.length;
-      // TODO: Use an efficient string search (e.g. BMH).
-      for (int index = start; index <= maxIndex; index++) {
-        if (_substringMatches(index, other)) {
-          return index;
-        }
-      }
-      return -1;
-    }
-    for (int i = start; i <= this.length; i++) {
-      // TODO(11276); This has quadratic behavior because matchAsPrefix tries
-      // to find a later match too. Optimize matchAsPrefix to avoid this.
-      if (pattern.matchAsPrefix(this, i) != null) return i;
-    }
-    return -1;
-  }
-
-  int lastIndexOf(Pattern pattern, [int? start]) {
-    if (start == null) {
-      start = this.length;
-    } else if (start < 0 || start > this.length) {
-      throw new RangeError.range(start, 0, this.length);
-    }
-    if (pattern is String) {
-      String other = pattern;
-      int maxIndex = this.length - other.length;
-      if (maxIndex < start) start = maxIndex;
-      for (int index = start; index >= 0; index--) {
-        if (_substringMatches(index, other)) {
-          return index;
-        }
-      }
-      return -1;
-    }
-    for (int i = start; i >= 0; i--) {
-      // TODO(11276); This has quadratic behavior because matchAsPrefix tries
-      // to find a later match too. Optimize matchAsPrefix to avoid this.
-      if (pattern.matchAsPrefix(this, i) != null) return i;
-    }
-    return -1;
-  }
-
-  String substring(int startIndex, [int? endIndex]) {
-    endIndex = RangeError.checkValidRange(startIndex, endIndex, this.length);
-    return _substringUnchecked(startIndex, endIndex);
-  }
-
-  String _substringUnchecked(int startIndex, int endIndex) {
-    assert((startIndex >= 0) && (startIndex <= this.length));
-    assert((endIndex >= 0) && (endIndex <= this.length));
-    assert(startIndex <= endIndex);
-
-    if (startIndex == endIndex) {
-      return "";
-    }
-    if ((startIndex == 0) && (endIndex == this.length)) {
-      return this;
-    }
-    if ((startIndex + 1) == endIndex) {
-      return this[startIndex];
-    }
-    return _substringUncheckedInternal(startIndex, endIndex);
-  }
-
-  String _substringUncheckedInternal(int startIndex, int endIndex);
-
-  // Checks for one-byte whitespaces only.
-  static bool _isOneByteWhitespace(int codeUnit) {
-    if (codeUnit <= 32) {
-      return ((codeUnit == 32) || // Space.
-          ((codeUnit <= 13) && (codeUnit >= 9))); // CR, LF, TAB, etc.
-    }
-    return (codeUnit == 0x85) || (codeUnit == 0xA0); // NEL, NBSP.
-  }
-
-  // Characters with Whitespace property (Unicode 6.3).
-  // 0009..000D    ; White_Space # Cc       <control-0009>..<control-000D>
-  // 0020          ; White_Space # Zs       SPACE
-  // 0085          ; White_Space # Cc       <control-0085>
-  // 00A0          ; White_Space # Zs       NO-BREAK SPACE
-  // 1680          ; White_Space # Zs       OGHAM SPACE MARK
-  // 2000..200A    ; White_Space # Zs       EN QUAD..HAIR SPACE
-  // 2028          ; White_Space # Zl       LINE SEPARATOR
-  // 2029          ; White_Space # Zp       PARAGRAPH SEPARATOR
-  // 202F          ; White_Space # Zs       NARROW NO-BREAK SPACE
-  // 205F          ; White_Space # Zs       MEDIUM MATHEMATICAL SPACE
-  // 3000          ; White_Space # Zs       IDEOGRAPHIC SPACE
-  //
-  // BOM: 0xFEFF
-  static bool _isTwoByteWhitespace(int codeUnit) {
-    if (codeUnit <= 32) {
-      return (codeUnit == 32) || ((codeUnit <= 13) && (codeUnit >= 9));
-    }
-    if (codeUnit < 0x85) return false;
-    if ((codeUnit == 0x85) || (codeUnit == 0xA0)) return true;
-    return (codeUnit <= 0x200A)
-        ? ((codeUnit == 0x1680) || (0x2000 <= codeUnit))
-        : ((codeUnit == 0x2028) ||
-            (codeUnit == 0x2029) ||
-            (codeUnit == 0x202F) ||
-            (codeUnit == 0x205F) ||
-            (codeUnit == 0x3000) ||
-            (codeUnit == 0xFEFF));
-  }
-
-  int _firstNonWhitespace() {
-    final len = this.length;
-    int first = 0;
-    for (; first < len; first++) {
-      if (!_isWhitespace(this.codeUnitAt(first))) {
-        break;
-      }
-    }
-    return first;
-  }
-
-  int _lastNonWhitespace() {
-    int last = this.length - 1;
-    for (; last >= 0; last--) {
-      if (!_isWhitespace(this.codeUnitAt(last))) {
-        break;
-      }
-    }
-    return last;
-  }
-
-  String trim() {
-    final len = this.length;
-    int first = _firstNonWhitespace();
-    if (len == first) {
-      // String contains only whitespaces.
-      return "";
-    }
-    int last = _lastNonWhitespace() + 1;
-    if ((first == 0) && (last == len)) {
-      // Returns this string since it does not have leading or trailing
-      // whitespaces.
-      return this;
-    }
-    return _substringUnchecked(first, last);
-  }
-
-  String trimLeft() {
-    final len = this.length;
-    int first = 0;
-    for (; first < len; first++) {
-      if (!_isWhitespace(this.codeUnitAt(first))) {
-        break;
-      }
-    }
-    if (len == first) {
-      // String contains only whitespaces.
-      return "";
-    }
-    if (first == 0) {
-      // Returns this string since it does not have leading or trailing
-      // whitespaces.
-      return this;
-    }
-    return _substringUnchecked(first, len);
-  }
-
-  String trimRight() {
-    final len = this.length;
-    int last = len - 1;
-    for (; last >= 0; last--) {
-      if (!_isWhitespace(this.codeUnitAt(last))) {
-        break;
-      }
-    }
-    if (last == -1) {
-      // String contains only whitespaces.
-      return "";
-    }
-    if (last == (len - 1)) {
-      // Returns this string since it does not have trailing whitespaces.
-      return this;
-    }
-    return _substringUnchecked(0, last + 1);
-  }
-
-  String operator *(int times) {
-    if (times <= 0) return "";
-    if (times == 1) return this;
-    StringBuffer buffer = new StringBuffer(this);
-    for (int i = 1; i < times; i++) {
-      buffer.write(this);
-    }
-    return buffer.toString();
-  }
-
-  String padLeft(int width, [String padding = ' ']) {
-    int delta = width - this.length;
-    if (delta <= 0) return this;
-    StringBuffer buffer = new StringBuffer();
-    for (int i = 0; i < delta; i++) {
-      buffer.write(padding);
-    }
-    buffer.write(this);
-    return buffer.toString();
-  }
-
-  String padRight(int width, [String padding = ' ']) {
-    int delta = width - this.length;
-    if (delta <= 0) return this;
-    StringBuffer buffer = new StringBuffer(this);
-    for (int i = 0; i < delta; i++) {
-      buffer.write(padding);
-    }
-    return buffer.toString();
-  }
-
-  bool contains(Pattern pattern, [int startIndex = 0]) {
-    if (pattern is String) {
-      if (startIndex < 0 || startIndex > this.length) {
-        throw new RangeError.range(startIndex, 0, this.length);
-      }
-      return indexOf(pattern, startIndex) >= 0;
-    }
-    return pattern.allMatches(this.substring(startIndex)).isNotEmpty;
-  }
-
-  String replaceFirst(Pattern pattern, String replacement,
-      [int startIndex = 0]) {
-    RangeError.checkValueInInterval(startIndex, 0, this.length, "startIndex");
-    Iterator iterator = startIndex == 0
-        ? pattern.allMatches(this).iterator
-        : pattern.allMatches(this, startIndex).iterator;
-    if (!iterator.moveNext()) return this;
-    Match match = iterator.current;
-    return replaceRange(match.start, match.end, replacement);
-  }
-
-  String replaceRange(int start, int? end, String replacement) {
-    final length = this.length;
-    final localEnd = RangeError.checkValidRange(start, end, length);
-    bool replacementIsOneByte = replacement._isOneByte;
-    if (start == 0 && localEnd == length) return replacement;
-    int replacementLength = replacement.length;
-    int totalLength = start + (length - localEnd) + replacementLength;
-    if (replacementIsOneByte && this._isOneByte) {
-      var result = _OneByteString._allocate(totalLength);
-      int index = 0;
-      index = result._setRange(index, this, 0, start);
-      index = result._setRange(start, replacement, 0, replacementLength);
-      result._setRange(index, this, localEnd, length);
-      return result;
-    }
-    List slices = [];
-    _addReplaceSlice(slices, 0, start);
-    if (replacement.length > 0) slices.add(replacement);
-    _addReplaceSlice(slices, localEnd, length);
-    return _joinReplaceAllResult(
-        this, slices, totalLength, replacementIsOneByte);
-  }
-
-  static int _addReplaceSlice(List matches, int start, int end) {
-    int length = end - start;
-    if (length > 0) {
-      if (length <= _maxLengthValue && start <= _maxStartValue) {
-        matches.add(-((start << _lengthBits) | length));
-      } else {
-        matches.add(start);
-        matches.add(end);
-      }
-    }
-    return length;
-  }
-
-  String replaceAll(Pattern pattern, String replacement) {
-    int startIndex = 0;
-    // String fragments that replace the prefix [this] up to [startIndex].
-    List matches = [];
-    int length = 0; // Length of all fragments.
-    int replacementLength = replacement.length;
-
-    if (replacementLength == 0) {
-      for (Match match in pattern.allMatches(this)) {
-        length += _addReplaceSlice(matches, startIndex, match.start);
-        startIndex = match.end;
-      }
-    } else {
-      for (Match match in pattern.allMatches(this)) {
-        length += _addReplaceSlice(matches, startIndex, match.start);
-        matches.add(replacement);
-        length += replacementLength;
-        startIndex = match.end;
-      }
-    }
-    // No match, or a zero-length match at start with zero-length replacement.
-    if (startIndex == 0 && length == 0) return this;
-    length += _addReplaceSlice(matches, startIndex, this.length);
-    bool replacementIsOneByte = replacement._isOneByte;
-    if (replacementIsOneByte &&
-        length < _maxJoinReplaceOneByteStringLength &&
-        this._isOneByte) {
-      // TODO(lrn): Is there a cut-off point, or is runtime always faster?
-      return _joinReplaceAllOneByteResult(this, matches, length);
-    }
-    return _joinReplaceAllResult(this, matches, length, replacementIsOneByte);
-  }
-
-  /**
-   * As [_joinReplaceAllResult], but knowing that the result
-   * is always a [_OneByteString].
-   */
-  static String _joinReplaceAllOneByteResult(
-      String base, List matches, int length) {
-    _OneByteString result = _OneByteString._allocate(length);
-    int writeIndex = 0;
-    for (int i = 0; i < matches.length; i++) {
-      var entry = matches[i];
-      if (entry is _Smi) {
-        int sliceStart = entry;
-        int sliceEnd;
-        if (sliceStart < 0) {
-          int bits = -sliceStart;
-          int sliceLength = bits & _lengthMask;
-          sliceStart = bits >> _lengthBits;
-          sliceEnd = sliceStart + sliceLength;
-        } else {
-          i++;
-          // This function should only be called with valid matches lists.
-          // If the list is short, or sliceEnd is not an integer, one of
-          // the next few lines will throw anyway.
-          assert(i < matches.length);
-          sliceEnd = matches[i];
-        }
-        for (int j = sliceStart; j < sliceEnd; j++) {
-          result._setAt(writeIndex++, base.codeUnitAt(j));
-        }
-      } else {
-        // Replacement is a one-byte string.
-        String replacement = entry;
-        for (int j = 0; j < replacement.length; j++) {
-          result._setAt(writeIndex++, replacement.codeUnitAt(j));
-        }
-      }
-    }
-    assert(writeIndex == length);
-    return result;
-  }
-
-  /**
-   * Combine the results of a [replaceAll] match into a new string.
-   *
-   * The [matches] lists contains Smi index pairs representing slices of
-   * [base] and [String]s to be put in between the slices.
-   *
-   * The total [length] of the resulting string is known, as is
-   * whether the replacement strings are one-byte strings.
-   * If they are, then we have to check the base string slices to know
-   * whether the result must be a one-byte string.
-   */
-
-  String _joinReplaceAllResult(String base, List matches, int length,
-      bool replacementStringsAreOneByte) {
-    if (length < 0) throw ArgumentError.value(length);
-    bool isOneByte = replacementStringsAreOneByte &&
-        _slicesAreOneByte(base, matches, length);
-    if (isOneByte) {
-      return _joinReplaceAllOneByteResult(base, matches, length);
-    }
-    _TwoByteString result = _TwoByteString._allocate(length);
-    int writeIndex = 0;
-    for (int i = 0; i < matches.length; i++) {
-      var entry = matches[i];
-      if (entry is _Smi) {
-        int sliceStart = entry;
-        int sliceEnd;
-        if (sliceStart < 0) {
-          int bits = -sliceStart;
-          int sliceLength = bits & _lengthMask;
-          sliceStart = bits >> _lengthBits;
-          sliceEnd = sliceStart + sliceLength;
-        } else {
-          i++;
-          // This function should only be called with valid matches lists.
-          // If the list is short, or sliceEnd is not an integer, one of
-          // the next few lines will throw anyway.
-          assert(i < matches.length);
-          sliceEnd = matches[i];
-        }
-        for (int j = sliceStart; j < sliceEnd; j++) {
-          result._setAt(writeIndex++, base.codeUnitAt(j));
-        }
-      } else {
-        // Replacement is a one-byte string.
-        String replacement = entry;
-        for (int j = 0; j < replacement.length; j++) {
-          result._setAt(writeIndex++, replacement.codeUnitAt(j));
-        }
-      }
-    }
-    assert(writeIndex == length);
-    return result;
-  }
-
-  bool _slicesAreOneByte(String base, List matches, int length) {
-    for (int i = 0; i < matches.length; i++) {
-      Object? o = matches[i];
-      if (o is int) {
-        int sliceStart = o;
-        int sliceEnd;
-        if (sliceStart < 0) {
-          int bits = -sliceStart;
-          int sliceLength = bits & _lengthMask;
-          sliceStart = bits >> _lengthBits;
-          sliceEnd = sliceStart + sliceLength;
-        } else {
-          i++;
-          if (i >= length) {
-            // Invalid, handled later.
-            return false;
-          }
-          Object? p = matches[i];
-          if (p is! int) {
-            // Invalid, handled later.
-            return false;
-          }
-          sliceEnd = p;
-        }
-        for (int j = sliceStart; j < sliceEnd; j++) {
-          if (base.codeUnitAt(j) > 0xff) {
-            return false;
-          }
-        }
-      }
-    }
-    return true;
-  }
-
-  String replaceAllMapped(Pattern pattern, String replace(Match match)) {
-    List matches = [];
-    int length = 0;
-    int startIndex = 0;
-    bool replacementStringsAreOneByte = true;
-    for (Match match in pattern.allMatches(this)) {
-      length += _addReplaceSlice(matches, startIndex, match.start);
-      var replacement = "${replace(match)}";
-      matches.add(replacement);
-      length += replacement.length;
-      replacementStringsAreOneByte =
-          replacementStringsAreOneByte && replacement._isOneByte;
-      startIndex = match.end;
-    }
-    if (matches.isEmpty) return this;
-    length += _addReplaceSlice(matches, startIndex, this.length);
-    if (replacementStringsAreOneByte &&
-        length < _maxJoinReplaceOneByteStringLength &&
-        this._isOneByte) {
-      return _joinReplaceAllOneByteResult(this, matches, length);
-    }
-    return _joinReplaceAllResult(
-        this, matches, length, replacementStringsAreOneByte);
-  }
-
-  String replaceFirstMapped(Pattern pattern, String replace(Match match),
-      [int startIndex = 0]) {
-    RangeError.checkValueInInterval(startIndex, 0, this.length, "startIndex");
-
-    var matches = pattern.allMatches(this, startIndex).iterator;
-    if (!matches.moveNext()) return this;
-    var match = matches.current;
-    var replacement = "${replace(match)}";
-    return replaceRange(match.start, match.end, replacement);
-  }
-
-  static String _matchString(Match match) => match[0]!;
-  static String _stringIdentity(String string) => string;
-
-  String _splitMapJoinEmptyString(
-      String onMatch(Match match), String onNonMatch(String nonMatch)) {
-    // Pattern is the empty string.
-    StringBuffer buffer = new StringBuffer();
-    int length = this.length;
-    int i = 0;
-    buffer.write(onNonMatch(""));
-    while (i < length) {
-      buffer.write(onMatch(new StringMatch(i, this, "")));
-      // Special case to avoid splitting a surrogate pair.
-      int code = this.codeUnitAt(i);
-      if ((code & ~0x3FF) == 0xD800 && length > i + 1) {
-        // Leading surrogate;
-        code = this.codeUnitAt(i + 1);
-        if ((code & ~0x3FF) == 0xDC00) {
-          // Matching trailing surrogate.
-          buffer.write(onNonMatch(this.substring(i, i + 2)));
-          i += 2;
-          continue;
-        }
-      }
-      buffer.write(onNonMatch(this[i]));
-      i++;
-    }
-    buffer.write(onMatch(new StringMatch(i, this, "")));
-    buffer.write(onNonMatch(""));
-    return buffer.toString();
-  }
-
-  String splitMapJoin(Pattern pattern,
-      {String onMatch(Match match)?, String onNonMatch(String nonMatch)?}) {
-    onMatch ??= _matchString;
-    onNonMatch ??= _stringIdentity;
-    if (pattern is String) {
-      String stringPattern = pattern;
-      if (stringPattern.isEmpty) {
-        return _splitMapJoinEmptyString(onMatch, onNonMatch);
-      }
-    }
-    StringBuffer buffer = new StringBuffer();
-    int startIndex = 0;
-    for (Match match in pattern.allMatches(this)) {
-      buffer.write(onNonMatch(this.substring(startIndex, match.start)));
-      buffer.write(onMatch(match).toString());
-      startIndex = match.end;
-    }
-    buffer.write(onNonMatch(this.substring(startIndex)));
-    return buffer.toString();
-  }
-
-  /**
-   * Convert all objects in [values] to strings and concat them
-   * into a result string.
-   * Modifies the input list if it contains non-`String` values.
-   */
-  @pragma("wasm:entry-point", "call")
-  static String _interpolate(final List<Object?> values) {
-    final numValues = values.length;
-    int totalLength = 0;
-    int i = 0;
-    while (i < numValues) {
-      final e = values[i];
-      final s = e.toString();
-      values[i] = s;
-      if (s is _OneByteString) {
-        totalLength += s.length;
-        i++;
-      } else {
-        // Handle remaining elements without checking for one-byte-ness.
-        while (++i < numValues) {
-          final e = values[i];
-          values[i] = e.toString();
-        }
-        return _concatRangeNative(values, 0, numValues);
-      }
-    }
-    // All strings were one-byte strings.
-    return _OneByteString._concatAll(values, totalLength);
-  }
-
-  static ArgumentError _interpolationError(Object? o, Object? result) {
-    // Since Dart 2.0, [result] can only be null.
-    return new ArgumentError.value(
-        o, "object", "toString method returned 'null'");
-  }
-
-  Iterable<Match> allMatches(String string, [int start = 0]) {
-    if (start < 0 || start > string.length) {
-      throw new RangeError.range(start, 0, string.length, "start");
-    }
-    return new StringAllMatchesIterable(string, this, start);
-  }
-
-  Match? matchAsPrefix(String string, [int start = 0]) {
-    if (start < 0 || start > string.length) {
-      throw new RangeError.range(start, 0, string.length);
-    }
-    if (start + this.length > string.length) return null;
-    for (int i = 0; i < this.length; i++) {
-      if (string.codeUnitAt(start + i) != this.codeUnitAt(i)) {
-        return null;
-      }
-    }
-    return new StringMatch(start, string, this);
-  }
-
-  List<String> split(Pattern pattern) {
-    if ((pattern is String) && pattern.isEmpty) {
-      List<String> result =
-          new List<String>.generate(this.length, (int i) => this[i]);
-      return result;
-    }
-    int length = this.length;
-    Iterator iterator = pattern.allMatches(this).iterator;
-    if (length == 0 && iterator.moveNext()) {
-      // A matched empty string input returns the empty list.
-      return <String>[];
-    }
-    List<String> result = <String>[];
-    int startIndex = 0;
-    int previousIndex = 0;
-    // 'pattern' may not be implemented correctly and therefore we cannot
-    // call _substringUnchecked unless it is a trustworthy type (e.g. String).
-    while (true) {
-      if (startIndex == length || !iterator.moveNext()) {
-        result.add(this.substring(previousIndex, length));
-        break;
-      }
-      Match match = iterator.current;
-      if (match.start == length) {
-        result.add(this.substring(previousIndex, length));
-        break;
-      }
-      int endIndex = match.end;
-      if (startIndex == endIndex && endIndex == previousIndex) {
-        ++startIndex; // empty match, advance and restart
-        continue;
-      }
-      result.add(this.substring(previousIndex, match.start));
-      startIndex = previousIndex = endIndex;
-    }
-    return result;
-  }
-
-  List<int> get codeUnits => new CodeUnits(this);
-
-  Runes get runes => new Runes(this);
-
-  String toUpperCase() => _toUpperCase(this);
-
-  String toLowerCase() => _toLowerCase(this);
-
-  // Concatenate ['start', 'end'[ elements of 'strings'.
-  static String _concatRange(List<String> strings, int start, int end) {
-    if ((end - start) == 1) {
-      return strings[start];
-    }
-    return _concatRangeNative(strings, start, end);
-  }
-
-  // Call this method if all elements of [strings] are known to be strings
-  // but not all are known to be OneByteString(s).
-  static String _concatRangeNative(List<Object?> strings, int start, int end) {
-    int totalLength = 0;
-    for (int i = start; i < end; i++) {
-      final str = strings[i];
-      if (str is JSStringImpl) {
-        totalLength += str.length;
-      } else {
-        totalLength += unsafeCast<_StringBase>(str).length;
-      }
-    }
-    _TwoByteString result = _TwoByteString._allocate(totalLength);
-    int offset = 0;
-    for (int i = start; i < end; i++) {
-      final str = strings[i];
-      if (str is JSStringImpl) {
-        final length = str.length;
-        final to = result._array;
-        for (int j = 0; j < length; j++) {
-          to.write(offset++, str.codeUnitAt(j));
-        }
-      } else {
-        _StringBase s = unsafeCast<_StringBase>(strings[i]);
-        offset = s._copyIntoTwoByteString(result, offset);
-      }
-    }
-    return result;
-  }
-
-  int _copyIntoTwoByteString(_TwoByteString result, int offset);
-}
-
-@pragma("wasm:entry-point")
-final class _OneByteString extends _StringBase {
-  @pragma("wasm:entry-point")
-  WasmIntArray<WasmI8> _array;
-
-  _OneByteString._withLength(int length)
-      : _array = WasmIntArray<WasmI8>(length),
-        super._();
-
-  // Same hash as VM
-  @override
-  int _computeHashCode() {
-    WasmIntArray<WasmI8> array = _array;
-    int length = array.length;
-    int hash = 0;
-    for (int i = 0; i < length; i++) {
-      hash = stringCombineHashes(hash, array.readUnsigned(i));
-    }
-    return stringFinalizeHash(hash);
-  }
-
-  @override
-  int codeUnitAt(int index) {
-    RangeError.checkValueInInterval(index, 0, length - 1);
-    return _array.readUnsigned(index);
-  }
-
-  @override
-  int get length => _array.length;
-
-  @override
-  bool _isWhitespace(int codeUnit) {
-    return _StringBase._isOneByteWhitespace(codeUnit);
-  }
-
-  bool operator ==(Object other) {
-    return super == other;
-  }
-
-  @override
-  String _substringUncheckedInternal(int startIndex, int endIndex) {
-    int length = endIndex - startIndex;
-    var result = _OneByteString._withLength(length);
-    for (int i = 0; i < length; i++) {
-      result._setAt(i, codeUnitAt(startIndex + i));
-    }
-    return result;
-  }
-
-  List<String> _splitWithCharCode(int charCode) {
-    final parts = <String>[];
-    int i = 0;
-    int start = 0;
-    for (i = 0; i < this.length; ++i) {
-      if (this.codeUnitAt(i) == charCode) {
-        parts.add(this._substringUnchecked(start, i));
-        start = i + 1;
-      }
-    }
-    parts.add(this._substringUnchecked(start, i));
-    return parts;
-  }
-
-  List<String> split(Pattern pattern) {
-    if (pattern is _OneByteString && pattern.length == 1) {
-      return _splitWithCharCode(pattern.codeUnitAt(0));
-    }
-    return super.split(pattern);
-  }
-
-  // All element of 'strings' must be OneByteStrings.
-  static _concatAll(List strings, int totalLength) {
-    final result = _OneByteString._allocate(totalLength);
-    final to = result._array;
-    final stringsLength = strings.length;
-    int j = 0;
-    for (int s = 0; s < stringsLength; s++) {
-      final _OneByteString e = unsafeCast<_OneByteString>(strings[s]);
-      final from = e._array;
-      final length = from.length;
-      for (int i = 0; i < length; i++) {
-        to.write(j++, from.readUnsigned(i));
-      }
-    }
-    return result;
-  }
-
-  @override
-  int _copyIntoTwoByteString(_TwoByteString result, int offset) {
-    final from = _array;
-    final int length = from.length;
-    final to = result._array;
-    int j = offset;
-    for (int i = 0; i < length; i++) {
-      to.write(j++, from.readUnsigned(i));
-    }
-    return j;
-  }
-
-  int indexOf(Pattern pattern, [int start = 0]) {
-    final len = this.length;
-    // Specialize for single character pattern.
-    if (pattern is String && pattern.length == 1 && start >= 0 && start < len) {
-      final patternCu0 = pattern.codeUnitAt(0);
-      if (patternCu0 > 0xFF) {
-        return -1;
-      }
-      for (int i = start; i < len; i++) {
-        if (this.codeUnitAt(i) == patternCu0) {
-          return i;
-        }
-      }
-      return -1;
-    }
-    return super.indexOf(pattern, start);
-  }
-
-  bool contains(Pattern pattern, [int start = 0]) {
-    final len = this.length;
-    if (pattern is String && pattern.length == 1 && start >= 0 && start < len) {
-      final patternCu0 = pattern.codeUnitAt(0);
-      if (patternCu0 > 0xFF) {
-        return false;
-      }
-      for (int i = start; i < len; i++) {
-        if (this.codeUnitAt(i) == patternCu0) {
-          return true;
-        }
-      }
-      return false;
-    }
-    return super.contains(pattern, start);
-  }
-
-  String operator *(int times) {
-    if (times <= 0) return "";
-    if (times == 1) return this;
-    int length = this.length;
-    if (this.isEmpty) return this; // Don't clone empty string.
-    _OneByteString result = _OneByteString._allocate(length * times);
-    int index = 0;
-    for (int i = 0; i < times; i++) {
-      for (int j = 0; j < length; j++) {
-        result._setAt(index++, this.codeUnitAt(j));
-      }
-    }
-    return result;
-  }
-
-  String padLeft(int width, [String padding = ' ']) {
-    if (!padding._isOneByte) {
-      return super.padLeft(width, padding);
-    }
-    int length = this.length;
-    int delta = width - length;
-    if (delta <= 0) return this;
-    int padLength = padding.length;
-    int resultLength = padLength * delta + length;
-    _OneByteString result = _OneByteString._allocate(resultLength);
-    int index = 0;
-    if (padLength == 1) {
-      int padChar = padding.codeUnitAt(0);
-      for (int i = 0; i < delta; i++) {
-        result._setAt(index++, padChar);
-      }
-    } else {
-      for (int i = 0; i < delta; i++) {
-        for (int j = 0; j < padLength; j++) {
-          result._setAt(index++, padding.codeUnitAt(j));
-        }
-      }
-    }
-    for (int i = 0; i < length; i++) {
-      result._setAt(index++, this.codeUnitAt(i));
-    }
-    return result;
-  }
-
-  String padRight(int width, [String padding = ' ']) {
-    if (!padding._isOneByte) {
-      return super.padRight(width, padding);
-    }
-    int length = this.length;
-    int delta = width - length;
-    if (delta <= 0) return this;
-    int padLength = padding.length;
-    int resultLength = length + padLength * delta;
-    _OneByteString result = _OneByteString._allocate(resultLength);
-    int index = 0;
-    for (int i = 0; i < length; i++) {
-      result._setAt(index++, this.codeUnitAt(i));
-    }
-    if (padLength == 1) {
-      int padChar = padding.codeUnitAt(0);
-      for (int i = 0; i < delta; i++) {
-        result._setAt(index++, padChar);
-      }
-    } else {
-      for (int i = 0; i < delta; i++) {
-        for (int j = 0; j < padLength; j++) {
-          result._setAt(index++, padding.codeUnitAt(j));
-        }
-      }
-    }
-    return result;
-  }
-
-  // Lower-case conversion table for Latin-1 as string.
-  // Upper-case ranges: 0x41-0x5a ('A' - 'Z'), 0xc0-0xd6, 0xd8-0xde.
-  // Conversion to lower case performed by adding 0x20.
-  static const _LC_TABLE =
-      "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
-      "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
-      "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f"
-      "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f"
-      "\x40\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f"
-      "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x5b\x5c\x5d\x5e\x5f"
-      "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f"
-      "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f"
-      "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
-      "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
-      "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf"
-      "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
-      "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
-      "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xd7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xdf"
-      "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
-      "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff";
-
-  // Upper-case conversion table for Latin-1 as string.
-  // Lower-case ranges: 0x61-0x7a ('a' - 'z'), 0xe0-0xff.
-  // The characters 0xb5 (µ) and 0xff (ÿ) have upper case variants
-  // that are not Latin-1. These are both marked as 0x00 in the table.
-  // The German "sharp s" \xdf (ß) should be converted into two characters (SS),
-  // and is also marked with 0x00.
-  // Conversion to lower case performed by subtracting 0x20.
-  static const _UC_TABLE =
-      "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
-      "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
-      "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f"
-      "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f"
-      "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f"
-      "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f"
-      "\x60\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f"
-      "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x7b\x7c\x7d\x7e\x7f"
-      "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
-      "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
-      "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf"
-      "\xb0\xb1\xb2\xb3\xb4\x00\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
-      "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
-      "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\x00"
-      "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
-      "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xf7\xd8\xd9\xda\xdb\xdc\xdd\xde\x00";
-
-  String toLowerCase() {
-    for (int i = 0; i < this.length; i++) {
-      final c = this.codeUnitAt(i);
-      if (c == _LC_TABLE.codeUnitAt(c)) continue;
-      // Upper-case character found.
-      final result = _allocate(this.length);
-      for (int j = 0; j < i; j++) {
-        result._setAt(j, this.codeUnitAt(j));
-      }
-      for (int j = i; j < this.length; j++) {
-        result._setAt(j, _LC_TABLE.codeUnitAt(this.codeUnitAt(j)));
-      }
-      return result;
-    }
-    return this;
-  }
-
-  String toUpperCase() {
-    for (int i = 0; i < this.length; i++) {
-      final c = this.codeUnitAt(i);
-      // Continue loop if character is unchanged by upper-case conversion.
-      if (c == _UC_TABLE.codeUnitAt(c)) continue;
-
-      // Check rest of string for characters that do not convert to
-      // single-characters in the Latin-1 range.
-      for (int j = i; j < this.length; j++) {
-        final c = this.codeUnitAt(j);
-        if ((_UC_TABLE.codeUnitAt(c) == 0x00) && (c != 0x00)) {
-          // We use the 0x00 value for characters other than the null character,
-          // that don't convert to a single Latin-1 character when upper-cased.
-          // In that case, call the generic super-class method.
-          return super.toUpperCase();
-        }
-      }
-      // Some lower-case characters found, but all upper-case to single Latin-1
-      // characters.
-      final result = _allocate(this.length);
-      for (int j = 0; j < i; j++) {
-        result._setAt(j, this.codeUnitAt(j));
-      }
-      for (int j = i; j < this.length; j++) {
-        result._setAt(j, _UC_TABLE.codeUnitAt(this.codeUnitAt(j)));
-      }
-      return result;
-    }
-    return this;
-  }
-
-  // Allocates a string of given length, expecting its content to be
-  // set using _setAt.
-
-  static _OneByteString _allocate(int length) {
-    return _OneByteString._withLength(length);
-  }
-
-  external static _OneByteString _allocateFromOneByteList(
-      List<int> list, int start, int end);
-
-  /// This is internal helper method. Code point value must be a valid Latin1
-  /// value (0..0xFF), index must be valid.
-  @pragma('wasm:prefer-inline')
-  void _setAt(int index, int codePoint) {
-    _array.write(index, codePoint);
-  }
-
-  // Should be optimizable to a memory move.
-  // Accepts both _OneByteString and _ExternalOneByteString as argument.
-  // Returns index after last character written.
-  int _setRange(int index, String oneByteString, int start, int end) {
-    assert(oneByteString._isOneByte);
-    assert(0 <= start);
-    assert(start <= end);
-    assert(end <= oneByteString.length);
-    assert(0 <= index);
-    assert(index + (end - start) <= length);
-    for (int i = start; i < end; i++) {
-      _setAt(index, oneByteString.codeUnitAt(i));
-      index += 1;
-    }
-    return index;
-  }
-}
-
-@pragma("wasm:entry-point")
-final class _TwoByteString extends _StringBase {
-  @pragma("wasm:entry-point")
-  WasmIntArray<WasmI16> _array;
-
-  _TwoByteString._withLength(int length)
-      : _array = WasmIntArray<WasmI16>(length),
-        super._();
-
-  // Same hash as VM
-  @override
-  int _computeHashCode() {
-    WasmIntArray<WasmI16> array = _array;
-    int length = array.length;
-    int hash = 0;
-    for (int i = 0; i < length; i++) {
-      hash = stringCombineHashes(hash, array.readUnsigned(i));
-    }
-    return stringFinalizeHash(hash);
-  }
-
-  // Allocates a string of given length, expecting its content to be
-  // set using _setAt.
-
-  static _TwoByteString _allocate(int length) =>
-      _TwoByteString._withLength(length);
-
-  static String _allocateFromTwoByteList(List<int> list, int start, int end) {
-    final int length = end - start;
-    final s = _allocate(length);
-    final array = s._array;
-    for (int i = 0; i < length; i++) {
-      array.write(i, list[start + i]);
-    }
-    return s;
-  }
-
-  /// This is internal helper method. Code point value must be a valid UTF-16
-  /// value (0..0xFFFF), index must be valid.
-  @pragma('wasm:prefer-inline')
-  void _setAt(int index, int codePoint) {
-    _array.write(index, codePoint);
-  }
-
-  @override
-  bool _isWhitespace(int codeUnit) {
-    return _StringBase._isTwoByteWhitespace(codeUnit);
-  }
-
-  @override
-  int codeUnitAt(int index) {
-    RangeError.checkValueInInterval(index, 0, length - 1);
-    return _array.readUnsigned(index);
-  }
-
-  @override
-  int get length => _array.length;
-
-  bool operator ==(Object other) {
-    return super == other;
-  }
-
-  @override
-  String _substringUncheckedInternal(int startIndex, int endIndex) {
-    int length = endIndex - startIndex;
-    var result = _TwoByteString._withLength(length);
-    for (int i = 0; i < length; i++) {
-      result._setAt(i, codeUnitAt(startIndex + i));
-    }
-    return result;
-  }
-
-  @override
-  int _copyIntoTwoByteString(_TwoByteString result, int offset) {
-    final from = _array;
-    final int length = from.length;
-    final to = result._array;
-    int j = offset;
-    for (int i = 0; i < length; i++) {
-      to.write(j++, from.readUnsigned(i));
-    }
-    return j;
-  }
-}
diff --git a/sdk/lib/libraries.json b/sdk/lib/libraries.json
index ccbc9a0573d..b10df0631e7 100644
--- a/sdk/lib/libraries.json
+++ b/sdk/lib/libraries.json
@@ -150,37 +150,6 @@
       }
     }
   },
-  "wasm_stringref": {
-    "include": [
-      {
-        "target": "wasm_base"
-      }
-    ],
-    "libraries": {
-      "core": {
-        "uri": "core/core.dart",
-        "patches": [
-          "_internal/vm_shared/lib/array_patch.dart",
-          "_internal/vm_shared/lib/bigint_patch.dart",
-          "_internal/vm_shared/lib/bool_patch.dart",
-          "_internal/vm_shared/lib/date_patch.dart",
-          "_internal/vm_shared/lib/map_patch.dart",
-          "_internal/vm_shared/lib/null_patch.dart",
-          "_internal/wasm/lib/boxed_double.dart",
-          "_internal/wasm/lib/boxed_int.dart",
-          "_internal/wasm/lib/boxed_int_to_string.dart",
-          "_internal/wasm/lib/core_patch.dart",
-          "_internal/wasm/lib/date_patch_patch.dart",
-          "_internal/wasm/lib/int_common_patch.dart",
-          "_internal/wasm/lib/int_patch.dart",
-          "_internal/wasm/lib/string_buffer_patch.dart",
-          "_internal/wasm/lib/string_stringref_patch.dart",
-          "_internal/wasm/lib/sync_star_patch.dart",
-          "_internal/wasm/lib/weak_patch.dart"
-        ]
-      }
-    }
-  },
   "wasm_js_compatibility": {
     "include": [
       {
diff --git a/sdk/lib/libraries.yaml b/sdk/lib/libraries.yaml
index 7c7f3d5fec6..bb09968316b 100644
--- a/sdk/lib/libraries.yaml
+++ b/sdk/lib/libraries.yaml
@@ -137,31 +137,6 @@ wasm:
         - _internal/wasm/lib/sync_star_patch.dart
         - _internal/wasm/lib/weak_patch.dart
 
-wasm_stringref:
-  include:
-    - target: "wasm_base"
-  libraries:
-    core:
-      uri: core/core.dart
-      patches:
-        - _internal/vm_shared/lib/array_patch.dart
-        - _internal/vm_shared/lib/bigint_patch.dart
-        - _internal/vm_shared/lib/bool_patch.dart
-        - _internal/vm_shared/lib/date_patch.dart
-        - _internal/vm_shared/lib/map_patch.dart
-        - _internal/vm_shared/lib/null_patch.dart
-        - _internal/wasm/lib/boxed_double.dart
-        - _internal/wasm/lib/boxed_int.dart
-        - _internal/wasm/lib/boxed_int_to_string.dart
-        - _internal/wasm/lib/core_patch.dart
-        - _internal/wasm/lib/date_patch_patch.dart
-        - _internal/wasm/lib/int_common_patch.dart
-        - _internal/wasm/lib/int_patch.dart
-        - _internal/wasm/lib/string_buffer_patch.dart
-        - _internal/wasm/lib/string_stringref_patch.dart
-        - _internal/wasm/lib/sync_star_patch.dart
-        - _internal/wasm/lib/weak_patch.dart
-
 wasm_js_compatibility:
   include:
     - target: "wasm_common"
diff --git a/tools/bots/test_matrix.json b/tools/bots/test_matrix.json
index 940b98e9240..24d2ea29a6a 100644
--- a/tools/bots/test_matrix.json
+++ b/tools/bots/test_matrix.json
@@ -122,8 +122,6 @@
       "out/ReleaseX64/dart2wasm_asserts.snapshot",
       "out/ReleaseX64/dart2wasm_outline.dill",
       "out/ReleaseX64/dart2wasm_platform.dill",
-      "out/ReleaseX64/dart2wasm_stringref_outline.dill",
-      "out/ReleaseX64/dart2wasm_stringref_platform.dill",
       "out/ReleaseX64/dart2wasm_js_compatibility_outline.dill",
       "out/ReleaseX64/dart2wasm_js_compatibility_platform.dill",
       "out/ReleaseX64/wasm/",
diff --git a/utils/dart2wasm/BUILD.gn b/utils/dart2wasm/BUILD.gn
index 226b0e9579a..ca7d50784bf 100644
--- a/utils/dart2wasm/BUILD.gn
+++ b/utils/dart2wasm/BUILD.gn
@@ -59,24 +59,6 @@ compile_platform("compile_dart2wasm_platform") {
   ]
 }
 
-compile_platform("compile_dart2wasm_stringref_platform") {
-  single_root_scheme = "org-dartlang-sdk"
-  single_root_base = rebase_path("$sdk_root/")
-  libraries_specification_uri = "org-dartlang-sdk:///lib/libraries.json"
-
-  outputs = [
-    "$root_out_dir/dart2wasm_stringref_platform.dill",
-    "$root_out_dir/dart2wasm_stringref_outline.dill",
-  ]
-
-  args = [
-    "--target=dart2wasm_stringref",
-    "--no-defines",
-    "dart:core",
-    "--nnbd-strong",
-  ]
-}
-
 compile_platform("compile_dart2wasm_js_compatibility_platform") {
   single_root_scheme = "org-dartlang-sdk"
   single_root_base = rebase_path("$sdk_root/")