misc(Goldens): Add some examples of template expressions.

Most of these correctly are emitted as expressions that are non-dynamic.

Notably:
  * Using collection literals (`[]`, `{}`) causes a dynamic call.
  * Using nested `*ngFor` causes a dynamic call.

There are probably other ways to (accidentally) cause a dynamic call that otherwise appears to be static. We should continue to add examples, as these would block the use of advanced Dart language features such as dart-lang/language#41 or dart-lang/sdk#35084 in the template.

PiperOrigin-RevId: 221693970

_goldens/test/_files/templates/dynamic_expressions.dart

@@ -0,0 +1,116 @@
+import 'package:angular/angular.dart';
+
+// OK: Compiles to "_ctx.a + _ctx.b"
+@Component(
+  selector: 'comp-1',
+  template: '{{a + b}}',
+)
+class Comp1 {
+  var a = 1;
+  var b = 2;
+}
+
+// OK: Compiles to "_ctx.a.b(_ctx.c)"
+@Component(
+  selector: 'comp-2',
+  template: '{{a.b(c)}}',
+)
+class Comp2 {
+  var a = Comp2Model();
+}
+
+class Comp2Model {
+  String b(String c) => c;
+}
+
+// OK: Compiles to "import1.Comp3.max(_ctx.a, _ctx.b).isEven"
+@Component(
+  selector: 'comp-3',
+  template: '{{max(a, b).isEven}}',
+)
+class Comp3 {
+  static T max<T extends Comparable<T>>(T a, T b) {
+    return a.compareTo(b) < 0 ? b : a;
+  }
+
+  var a = 0;
+  var b = 1;
+}
+
+// Dynamic :(
+//
+// Compiles to:
+//   "List<dynamic> Function(dynamic, dynamic) _arr_0;"
+//   "_arr_0 = import6.pureProxy2((p0, p1) => [p0, p1])"
+// ...
+//   "_arr_0(_ctx.a, _ctx.b).first.inMilliseconds"
+@Component(
+  selector: 'comp-4',
+  template: '{{[a, b].first.inMilliseconds}}',
+)
+class Comp4 {
+  var a = Duration(seconds: 1);
+  var b = Duration(seconds: 2);
+}
+
+// Dynamic :(
+//
+// Compiles to:
+//   "Map<String, dynamic> Function(dynamic) _map_0;"
+//   "_map_0 = import6.pureProxy1((p0) => {'1': p0}))"
+// ...
+//   "_map_0(_ctx.b).values.first.inMilliseconds"
+@Component(
+  selector: 'comp-5',
+  template: '{{{"1": b}.values.first.inMilliseconds}}}',
+)
+class Comp5 {
+  var v = Duration(seconds: 1);
+}
+
+// OK!
+//
+// Compiles to:
+//    "final local_duration = import7.unsafeCast<Duration>(locals['\$implicit']);"
+//    "final currVal_0 = import6.interpolate0(local_duration.inMilliseconds);"
+@Component(
+  selector: 'comp-6',
+  directives: [NgFor],
+  template: r'''
+    <ng-container *ngFor="let duration of durations">
+      {{duration.inMilliseconds}}
+    </ng-container>
+  ''',
+)
+class Comp6 {
+  var durations = [Duration(seconds: 1)];
+}
+
+// Dynamic :(
+//
+// Compiles to:
+//    "final local_durations = import7.unsafeCast<List<Duration>>(locals['\$implicit']);"
+//    "final currVal_0 = local_durations;"
+//    "if (import6.checkBinding(_expr_0, currVal_0)) {"
+//      "_NgFor_0_9.ngForOf = currVal_0;"
+//      "_expr_0 = currVal_0;"
+//    "}"
+// ...
+//    "final local_duration = locals['\$implicit'];"
+//    "final currVal_0 = import6.interpolate0(local_duration.inMilliseconds);"
+@Component(
+  selector: 'comp-7',
+  directives: [NgFor],
+  template: r'''
+    <ng-container *ngFor="let durations of items">
+      <ng-container *ngFor="let duration of durations">
+        {{duration.inMilliseconds}}
+      </ng-container>
+    </ng-container>
+  ''',
+)
+class Comp7 {
+  var items = [
+    [Duration(seconds: 1)]
+  ];
+}

_goldens/test/_files/templates/dynamic_expressions.outline.golden

@@ -0,0 +1,67 @@
+// ignore_for_file: library_prefixes,unused_import,no_default_super_constructor_explicit
+// The .template.dart files also export the user code.
+export 'dynamic_expressions.dart';
+
+// Required for referencing runtime code.
+import 'dart:html' as _html;
+import 'package:angular/angular.dart' as _ng;
+import 'package:angular/src/core/change_detection/directive_change_detector.dart' as _ng;
+import 'package:angular/src/core/linker/app_view.dart' as _ng;
+
+// Required for specifically referencing user code.
+import 'dynamic_expressions.dart';
+
+// Required for "type inference" (scoping).
+import 'package:angular/angular.dart';
+
+// For @Component class Comp1.
+external List<dynamic> get styles$Comp1;
+external _ng.ComponentFactory<Comp1> get Comp1NgFactory;
+external _ng.AppView<Comp1> viewFactory_Comp10(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp10 extends _ng.AppView<Comp1> {
+  external ViewComp10(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+// For @Component class Comp2.
+external List<dynamic> get styles$Comp2;
+external _ng.ComponentFactory<Comp2> get Comp2NgFactory;
+external _ng.AppView<Comp2> viewFactory_Comp20(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp20 extends _ng.AppView<Comp2> {
+  external ViewComp20(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+// For @Component class Comp3.
+external List<dynamic> get styles$Comp3;
+external _ng.ComponentFactory<Comp3> get Comp3NgFactory;
+external _ng.AppView<Comp3> viewFactory_Comp30(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp30 extends _ng.AppView<Comp3> {
+  external ViewComp30(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+// For @Component class Comp4.
+external List<dynamic> get styles$Comp4;
+external _ng.ComponentFactory<Comp4> get Comp4NgFactory;
+external _ng.AppView<Comp4> viewFactory_Comp40(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp40 extends _ng.AppView<Comp4> {
+  external ViewComp40(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+// For @Component class Comp5.
+external List<dynamic> get styles$Comp5;
+external _ng.ComponentFactory<Comp5> get Comp5NgFactory;
+external _ng.AppView<Comp5> viewFactory_Comp50(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp50 extends _ng.AppView<Comp5> {
+  external ViewComp50(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+// For @Component class Comp6.
+external List<dynamic> get styles$Comp6;
+external _ng.ComponentFactory<Comp6> get Comp6NgFactory;
+external _ng.AppView<Comp6> viewFactory_Comp60(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp60 extends _ng.AppView<Comp6> {
+  external ViewComp60(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+// For @Component class Comp7.
+external List<dynamic> get styles$Comp7;
+external _ng.ComponentFactory<Comp7> get Comp7NgFactory;
+external _ng.AppView<Comp7> viewFactory_Comp70(_ng.AppView<dynamic> parentView, int parentIndex);
+class ViewComp70 extends _ng.AppView<Comp7> {
+  external ViewComp70(_ng.AppView<dynamic> parentView, int parentIndex);
+}
+
+external void initReflector();