[pkg:js] Lower external @staticInterop and extension members using invocation-level semantics

We've changed the semantics for these members using dart:js_interop
so that not passing in optionals on the Dart side is equivalent to
not passing in optionals on the JS side. This CL makes that consistent
with package:js as well.

Modifies CHANGELOG to announce breaking change.

Change-Id: Ic5c33c9c797983a72edec9bc59f60fc1f29240b4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/300400
Reviewed-by: Joshua Litt <joshualitt@google.com>
Commit-Queue: Srujan Gaddam <srujzs@google.com>

CHANGELOG.md

@@ -20,6 +20,14 @@
   `external` `@staticInterop` members and `external` extension members can no
   longer be used as tear-offs. Declare a closure or a non-`external` method that
   calls these members, and use that instead.
+- **Breaking change to `@staticInterop` and `external` extension members**:
+  `external` `@staticInterop` members and `external` extension members will
+  generate slightly different JS code for methods that have optional parameters.
+  Whereas before, the JS code passed in the default value for missing optionals,
+  it will now pass in only the provided members. This aligns with how JS
+  parameters work, where omitted parameters are actually omitted. For example,
+  calling `external void foo([int a, int b])` as `foo(0)` will now result in
+  `foo(0)`, and not `foo(0, null)`.
 
 ### Tools
 

pkg/_js_interop_checks/lib/src/transformations/js_util_optimizer.dart

@@ -930,31 +930,20 @@ class InlineExtensionIndex {
   /// member but rather lower directly to the interop procedure at the
   /// call-site. This is needed in order to support cases where omitted
   /// optional parameters shouldn't be passed.
-  ///
-  /// **Note that we only do this for users using `dart:js_interop`'s `@JS`
-  /// annotation. This means `@staticInterop` will behave slightly differently
-  /// depending on the import. This is to avoid a breaking change in the
-  /// existing semantics of `@staticInterop`.**
   bool canBeInvocationLevelLowered(Procedure node) {
-    if (hasDartJSInteropAnnotation(node) ||
-        hasDartJSInteropAnnotation(node.enclosingLibrary) ||
+    if (hasJSInteropAnnotation(node) ||
+        hasJSInteropAnnotation(node.enclosingLibrary) ||
         (node.enclosingClass != null &&
-            hasDartJSInteropAnnotation(node.enclosingClass!))) {
+            hasJSInteropAnnotation(node.enclosingClass!))) {
       return true;
     }
 
     if (node.isExtensionMember) {
-      final annotatable = getExtensionAnnotatable(node);
-      if (annotatable != null) {
-        return hasDartJSInteropAnnotation(annotatable);
-      }
+      return getExtensionAnnotatable(node) != null;
     }
 
     if (node.isInlineClassMember) {
-      final cls = getInlineClass(node);
-      if (cls != null) {
-        return hasDartJSInteropAnnotation(cls);
-      }
+      return getInlineClass(node) != null;
     }
 
     return false;

tests/lib/js/external_extension_members_test.dart

@@ -133,17 +133,6 @@ void main() {
     expect(foo.otherSumFn(10, 5), equals(15));
   });
 
-  // TODO(41375): Remove if JS interop default value arguments are disallowed.
-  test('optional arguments', () {
-    var foo = Foo(42);
-    expect(foo.field, equals(42));
-
-    foo.setField10();
-    expect(foo.field, equals(10));
-    foo.setField10(6);
-    expect(foo.field, equals(6));
-  });
-
   test('module class', () {
     var bar = Bar(5);
     expect(js_util.getProperty(bar, 'fieldAnnotation'), equals(5));

tests/lib_2/js/external_extension_members_test.dart

@@ -115,17 +115,6 @@ void main() {
     expect(foo.otherSumFn(10, 5), equals(15));
   });
 
-  // TODO(41375): Remove if JS interop default value arguments are disallowed.
-  test('optional arguments', () {
-    var foo = Foo(42);
-    expect(foo.getField(), equals(42));
-
-    foo.setField10();
-    expect(foo.getField(), equals(10));
-    foo.setField10(6);
-    expect(foo.getField(), equals(6));
-  });
-
   test('module class', () {
     var bar = Bar(5);
     expect(js_util.getProperty(bar, 'fieldAnnotation'), equals(5));