[vm/ffi] Fix mixin of _BoolArrayList

_BoolArrayList needs to extend FixedLengthListMixin instead of
UnmodifiableListMixin since it implements `operator []=`.

Also contains some other doc fixes that were brought up post-submit in
https://dart-review.googlesource.com/c/sdk/+/414821.

TEST=tests/ffi/array_primitive_elements_generated_test.dart

CoreLibraryReviewExempt: Dart VM only.
Bug: #45508
Change-Id: I7635152283aec51a4f38e06fdfc7da84e93e55ab
Cq-Include-Trybots: dart/try:vm-aot-android-release-arm64c-try,vm-aot-android-release-arm_x64-try,vm-aot-asan-linux-release-x64-try,vm-aot-linux-debug-x64-try,vm-aot-linux-debug-x64c-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-msan-linux-release-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-optimization-level-linux-release-x64-try,vm-aot-tsan-linux-release-x64-try,vm-aot-ubsan-linux-release-x64-try,vm-aot-win-debug-arm64-try,vm-aot-win-debug-x64-try,vm-aot-win-debug-x64c-try,vm-appjit-linux-debug-x64-try,vm-asan-linux-release-arm64-try,vm-asan-linux-release-x64-try,vm-checked-mac-release-arm64-try,vm-eager-optimization-linux-release-ia32-try,vm-eager-optimization-linux-release-x64-try,vm-ffi-android-debug-arm-try,vm-ffi-android-debug-arm64c-try,vm-ffi-mac-debug-simarm64_arm64-try,vm-ffi-qemu-linux-release-arm-try,vm-ffi-qemu-linux-release-riscv64-try,vm-fuchsia-release-arm64-try,vm-fuchsia-release-x64-try,vm-linux-debug-ia32-try,vm-linux-debug-x64-try,vm-linux-debug-x64c-try,vm-mac-debug-arm64-try,vm-mac-debug-x64-try,vm-msan-linux-release-arm64-try,vm-msan-linux-release-x64-try,vm-reload-linux-debug-x64-try,vm-reload-rollback-linux-debug-x64-try,vm-tsan-linux-release-arm64-try,vm-tsan-linux-release-x64-try,vm-ubsan-linux-release-arm64-try,vm-ubsan-linux-release-x64-try,vm-win-debug-arm64-try,vm-win-debug-x64-try,vm-win-debug-x64c-try,vm-win-release-ia32-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/417100
Reviewed-by: Daco Harkes <[email protected]>
Commit-Queue: Michael Goderbauer <[email protected]>

Author: goderbauer

runtime/tools/ffi/sdk_lib_ffi_generator.dart

@@ -106,7 +106,7 @@ void update(Uri fileName, Function(StringBuffer, Config, Container) generator) {
 
 const header = """
 //
-// The following code is generated, do not edit by hand.
+// Generated code, do not edit!
 //
 // Code generated by `runtime/tools/ffi/sdk_lib_ffi_generator.dart`.
 //
@@ -286,14 +286,23 @@ $asTypedList
       buffer.write("""
 /// Bounds checking indexing methods on [Array]s of [$nativeType].
 $since extension ${nativeType}Array on Array<$nativeType> {
+  /// Loads a Dart value from this array at [index].
+  ///
+  /// This extension method must be invoked on a receiver of type `Array<T>`
+  /// where `T` is a compile-time constant type.
   external $dartType operator [](int index);
 
+  /// Stores a Dart value in this array at [index].
+  ///
+  /// This extension method must be invoked on a receiver of type `Array<T>`
+  /// where `T` is a compile-time constant type.
   external void operator []=(int index, $dartType value);
 
   /// A list view of the bytes of this array.
   ///
   /// Has the same length and elements (as accessed using the index operator)
-  /// as this array, and writes to either the list or this arrary are visible in both.
+  /// as this array, and writes to either the list or this arrary are visible
+  /// in both.
   @Since('3.8')
   external $elementsGetterReturnType get elements;
 }
@@ -406,7 +415,7 @@ $asTypedList
   List<$dartType> get elements => _${nativeType}ArrayList(this);
 """;
         listHelperClass = """
-class _${nativeType}ArrayList with ListMixin<$dartType>, UnmodifiableListMixin<$dartType> {
+class _${nativeType}ArrayList with ListMixin<$dartType>, FixedLengthListMixin<$dartType> {
   _${nativeType}ArrayList(this._array);
 
   final Array<$nativeType> _array;

sdk/lib/_internal/vm/lib/ffi_patch.dart

@@ -657,7 +657,7 @@ extension NativeFunctionPointer<NF extends Function>
 }
 
 //
-// The following code is generated, do not edit by hand.
+// Generated code, do not edit!
 //
 // Code generated by `runtime/tools/ffi/sdk_lib_ffi_generator.dart`.
 //
@@ -1401,7 +1401,7 @@ extension BoolArray on Array<Bool> {
   List<bool> get elements => _BoolArrayList(this);
 }
 
-class _BoolArrayList with ListMixin<bool>, UnmodifiableListMixin<bool> {
+class _BoolArrayList with ListMixin<bool>, FixedLengthListMixin<bool> {
   _BoolArrayList(this._array);
 
   final Array<Bool> _array;