Make the NNBD List.empty default to non-growable. Since a growable list can be created using `[]`, you never need to call `List.empty` with anything but `growable: false` or `growable: dynamicValue`. That means that the default should be non-growable (which also matches `List.filled` and apparently user expectations - since there is already one bug where I assumed it would be non-grwowble while migrating List.generate). Ensure it's implemented by dart2js too and used where there were comments saying to use it when available. Change-Id: Ied20d69346ecfb93640ee2cec718e30e6f8980e8 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/132600 Reviewed-by: Stephen Adams <sra@google.com> Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>

diff --git a/sdk_nnbd/lib/_internal/js_dev_runtime/patch/core_patch.dart b/sdk_nnbd/lib/_internal/js_dev_runtime/patch/core_patch.dart
index 0cfb3f8..5180103 100644
--- a/sdk_nnbd/lib/_internal/js_dev_runtime/patch/core_patch.dart
+++ b/sdk_nnbd/lib/_internal/js_dev_runtime/patch/core_patch.dart

@@ -524,7 +524,7 @@
   }
 
   @patch
-  factory List.empty({bool growable = true}) {
+  factory List.empty({bool growable = false}) {
     var list = JSArray<E>.of(JS('', 'new Array()'));
     if (!growable) JSArray.markFixedList(list);
     return list;

diff --git a/sdk_nnbd/lib/_internal/js_runtime/lib/core_patch.dart b/sdk_nnbd/lib/_internal/js_runtime/lib/core_patch.dart
index cc6e81e..bfd0896 100644
--- a/sdk_nnbd/lib/_internal/js_runtime/lib/core_patch.dart
+++ b/sdk_nnbd/lib/_internal/js_runtime/lib/core_patch.dart

@@ -431,6 +431,11 @@
   }
 
   @patch
+  factory List.empty({bool growable = false}) {
+    return growable ? new JSArray<E>.growable(0) : new JSArray<E>.fixed(0);
+  }
+
+  @patch
   factory List.from(Iterable elements, {bool growable: true}) {
     List<E> list = <E>[];
     for (E e in elements) {

diff --git a/sdk_nnbd/lib/_internal/vm/lib/array_patch.dart b/sdk_nnbd/lib/_internal/vm/lib/array_patch.dart
index 6ad5297..ba97574 100644
--- a/sdk_nnbd/lib/_internal/vm/lib/array_patch.dart
+++ b/sdk_nnbd/lib/_internal/vm/lib/array_patch.dart

@@ -7,7 +7,7 @@
 @patch
 class List<E> {
   @patch
-  factory List.empty({bool growable = true}) {
+  factory List.empty({bool growable = false}) {
     return growable ? <E>[] : _List<E>(0);
   }
 

diff --git a/sdk_nnbd/lib/collection/list.dart b/sdk_nnbd/lib/collection/list.dart
index 2ae10f0..2b5452a 100644
--- a/sdk_nnbd/lib/collection/list.dart
+++ b/sdk_nnbd/lib/collection/list.dart

@@ -236,8 +236,7 @@
   }
 
   List<E> toList({bool growable = true}) {
-    // TODO(rnystrom): Use List.empty() instead once that lands.
-    if (this.isEmpty) return List<E>.of([], growable: growable);
+    if (this.isEmpty) return List<E>.empty(growable: growable);
     var first = this[0];
     var result = List<E>.filled(this.length, first, growable: growable);
     for (int i = 1; i < this.length; i++) {

diff --git a/sdk_nnbd/lib/collection/queue.dart b/sdk_nnbd/lib/collection/queue.dart
index 7174bc3..600ea6b 100644
--- a/sdk_nnbd/lib/collection/queue.dart
+++ b/sdk_nnbd/lib/collection/queue.dart

@@ -634,8 +634,7 @@
   List<E> toList({bool growable = true}) {
     int mask = _table.length - 1;
     int length = (_tail - _head) & mask;
-    // TODO(rnystrom): Use List.empty() when that's available.
-    if (length == 0) return List<E>.of([], growable: growable);
+    if (length == 0) return List<E>.empty(growable: growable);
 
     var list = List<E>.filled(length, first, growable: growable);
     for (int i = 0; i < length; i++) {

diff --git a/sdk_nnbd/lib/core/list.dart b/sdk_nnbd/lib/core/list.dart
index a6be658..e78f478 100644
--- a/sdk_nnbd/lib/core/list.dart
+++ b/sdk_nnbd/lib/core/list.dart

@@ -124,11 +124,12 @@
   /**
    * Creates a new empty list.
    *
-   * If [growable] is `true`, which is the default,
-   * the list is growable and equivalent to `<E>[]`.
-   * If [growable] is `false`, the list is a fixed-length list of length zero.
+   * If [growable] is `false`, which is the default,
+   * the list is a fixed-length list of length zero.
+   * If [growable] is `true`, the list is growable and equivalent to `<E>[]`.
    */
-  external factory List.empty({bool growable = true});
+  @Since("2.8")
+  external factory List.empty({bool growable = false});
 
   /**
    * Creates a list containing all [elements].