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[ddc] Cleanup false assumption from subtype check

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FutureOr<A> <: FutureOr<B> iff A <: B was proven to not always be true.
Changing this to simply an optimization and no longer "if and only if".

Change-Id: I46f228933df65a86c2c525a48f11b18397b7c48c
Fixes: https://github.com/dart-lang/sdk/issues/38818
Fixes: https://github.com/dart-lang/sdk/issues/42326
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151325
Reviewed-by: Mark Zhou <markzipan@google.com>
Commit-Queue: Nicholas Shahan <nshahan@google.com>
This commit is contained in:
Nicholas Shahan
2020-06-16 21:20:01 +00:00
committed by commit-bot@chromium.org
parent 62893f9b00
commit 07e2921287
2 changed files with 8 additions and 8 deletions
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sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/types.dart
+4 -4
View File
@@ -1415,10 +1415,10 @@ bool _isSubtype(t1, t2, @notNull bool strictMode) => JS<bool>('!', '''(() => {
let t1TypeArg = ${getGenericArgs(t1)}[0];
if (${_isFutureOr(t2)}) {
let t2TypeArg = ${getGenericArgs(t2)}[0];
// FutureOr<A> <: FutureOr<B> iff A <: B
// TODO(nshahan): Proven to not actually be true and needs cleanup.
// https://github.com/dart-lang/sdk/issues/38818
return $_isSubtype(t1TypeArg, t2TypeArg, $strictMode);
// FutureOr<A> <: FutureOr<B> if A <: B
if ($_isSubtype(t1TypeArg, t2TypeArg, $strictMode)) {
return true;
}
}
// given t1 is Future<A> | A, then:
sdk_nnbd/lib/_internal/js_dev_runtime/private/ddc_runtime/types.dart
+4 -4
View File
@@ -1413,10 +1413,10 @@ bool _isSubtype(t1, t2, @notNull bool strictMode) => JS<bool>('!', '''(() => {
let t1TypeArg = ${getGenericArgs(t1)}[0];
if (${_isFutureOr(t2)}) {
let t2TypeArg = ${getGenericArgs(t2)}[0];
// FutureOr<A> <: FutureOr<B> iff A <: B
// TODO(nshahan): Proven to not actually be true and needs cleanup.
// https://github.com/dart-lang/sdk/issues/38818
return $_isSubtype(t1TypeArg, t2TypeArg, $strictMode);
// FutureOr<A> <: FutureOr<B> if A <: B
if ($_isSubtype(t1TypeArg, t2TypeArg, $strictMode)) {
return true;
}
}
// given t1 is Future<A> | A, then: