From dc33261641ad775109fff90d835fcbb3e43ec509 Mon Sep 17 00:00:00 2001
From: Zach Anderson <zra@google.com>
Date: Wed, 5 Apr 2023 23:13:36 +0000
Subject: [PATCH] Revert "[dart2wasm] Fix runtime type tests"
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This reverts commit a289c4d84870d9d403307535d281f2f8fc79c2f5.

Reason for revert: https://github.com/flutter/flutter/issues/124282

Original change's description:
> [dart2wasm] Fix runtime type tests
>
> emitTypeTest optimizes a test like `x is List<T>` where `x :
> Iterable<T>`, i.e. tested-against type is a subtype of the operand's
> static type. In these cases we can check just the class ID of the
> operand without checking the type arguments.
>
> However this optimization cannot be done when the types don't have same
> number of type arguments. Example:
>
>     class H1<T> {}
>
>     bool test(Object o) {
>       return o is H1<num>;
>     }
>
>     void main() {
>       print(test(H1<Object>()));
>     }
>
> Here `H1<num> <: Object`, but we still need to check the type parameter.
>
> This CL checks that the types have the same number of type arguments
> before optimizing the test.
>
> Fixes #51187.
>
> This fix reveals another bug in `static_interop_test`, which is tracked
> in #51200. The test is updated to work around the bug for now.
>
> New passing tests:
>
> - co19/LanguageFeatures/Patterns/matching_cast_A01_t01
> - co19/LanguageFeatures/Patterns/matching_list_A01_t01
> - co19/LanguageFeatures/Patterns/matching_list_A01_t02
> - co19/LanguageFeatures/Patterns/matching_object_A01_t01
> - co19/LanguageFeatures/Patterns/matching_object_A01_t02
> - co19/LanguageFeatures/Patterns/record_A01_t03
> - co19/LanguageFeatures/Patterns/record_A01_t06
> - co19/LanguageFeatures/Patterns/record_A01_t07
> - co19/LanguageFeatures/Patterns/record_A01_t08
> - co19/LanguageFeatures/Patterns/record_A01_t09
> - language/generic/deep_test
> - language/generic_methods/type_expression_test
> - language/patterns/object_pattern_inference_test
>
> Change-Id: Ibd9615666b7f7538c2a3f03fb7f5ebe9b16c3d54
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/292881
> Reviewed-by: Joshua Litt <joshualitt@google.com>
> Commit-Queue: Ömer Ağacan <omersa@google.com>

Change-Id: Ieb222c086864744d33b77de69882e805981f1953
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/293891
Commit-Queue: Zach Anderson <zra@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Joshua Litt <joshualitt@google.com>
---
 pkg/dart2wasm/lib/types.dart            | 15 ++++-----------
 tests/web/wasm/static_interop_test.dart |  2 +-
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/pkg/dart2wasm/lib/types.dart b/pkg/dart2wasm/lib/types.dart
index 44daee549b0..9a9f3df4349 100644
--- a/pkg/dart2wasm/lib/types.dart
+++ b/pkg/dart2wasm/lib/types.dart
@@ -611,23 +611,16 @@ class Types {
     }
 
     if (type.typeArguments.any((t) => t is! DynamicType)) {
-      // Type has at least one type argument that is not `dynamic`.
-      //
-      // In cases like `x is List<T>` where `x : Iterable<T>` (tested-against
-      // type is a subtype of the operand's static type and the types have same
-      // number of type arguments), it is not necessary to test the type
-      // arguments.
+      // If the tested-against type as an instance of the static operand type
+      // has the same type arguments as the static operand type, it is not
+      // necessary to test the type arguments.
       Class cls = translator.classForType(operandType);
       InterfaceType? base = translator.hierarchy
           .getTypeAsInstanceOf(type, cls,
               isNonNullableByDefault:
                   codeGen.member.enclosingLibrary.isNonNullableByDefault)
           ?.withDeclaredNullability(operandType.declaredNullability);
-
-      final sameNumTypeParams = operandType is InterfaceType &&
-          operandType.typeArguments.length == type.typeArguments.length;
-
-      if (!(sameNumTypeParams && base == operandType)) {
+      if (base != operandType) {
         makeType(codeGen, type);
         codeGen.call(translator.isSubtype.reference);
         _endPotentiallyNullableBlock();
diff --git a/tests/web/wasm/static_interop_test.dart b/tests/web/wasm/static_interop_test.dart
index 3c66bd9d27e..25b7e7c54d8 100644
--- a/tests/web/wasm/static_interop_test.dart
+++ b/tests/web/wasm/static_interop_test.dart
@@ -311,7 +311,7 @@ extension AnonymousJSClassExtension on AnonymousJSClass {
   external String? get bleep;
   external int? get goo;
   external int? get ooo;
-  external List<Object?>? saz;
+  external List<double>? saz;
   external List<double>? zoo;
 }