Runtime errors potentially due to incomplete pattern desugaring in switch statements

[chloestefantsova]

The following tests started surfacing runtime errors after the switch-pattern desugaring was partially introduced. It's most likely that the incomplete desugaring is the root of the issue, and it will be resolved eventually as desugaring becomes more complete.

• co19/LanguageFeatures/Patterns/list_A01_t02 (additionally, possibly 'records' not enabled on dart2js tests)
• co19/LanguageFeatures/Patterns/logical_and_A06_t01
• co19/LanguageFeatures/Patterns/logical_or_A02_t02
• co19/LanguageFeatures/Patterns/logical_or_A05_t01
• co19/LanguageFeatures/Patterns/wildcards_A01_t04

The error was encountered during work on https://dart-review.googlesource.com/c/sdk/+/276524.

This issue is assigned label area-front-end tentatively, and it needs further investigation, and possibly reassignment of the tags.

[alexmarkov]

I can confirm that the following tests fail because Object pattern is not implemented yet:

co19/LanguageFeatures/Patterns/list_A01_t02
co19/LanguageFeatures/Patterns/logical_and_A06_t01
co19/LanguageFeatures/Patterns/logical_or_A05_t01
co19/LanguageFeatures/Patterns/wildcards_A01_t04

co19/LanguageFeatures/Patterns/logical_or_A02_t02 fails for another reason: #50797.

[chloestefantsova]

More of the failing tests for the same reason.

• tests/co19/src/LanguageFeatures/Patterns/list_A04_t05.dart
• co19/LanguageFeatures/Patterns/record_A01_t01
• co19/LanguageFeatures/Patterns/record_A01_t02
• co19/LanguageFeatures/Patterns/record_A01_t03
• co19/LanguageFeatures/Patterns/record_A01_t04

These are detected by the try bots on the following CL: https://dart-review.googlesource.com/c/sdk/+/276940.

[chloestefantsova]

One more example:

• co19/LanguageFeatures/Patterns/wildcards_A01_t01

[chloestefantsova]

More of the test failing due to the pattern desugaring being incomplete:

• co19/LanguageFeatures/Patterns/map_A04_t02
• co19/LanguageFeatures/Patterns/map_A05_t01
• co19/LanguageFeatures/Patterns/object_A01_t01
• co19/LanguageFeatures/Patterns/object_A02_t01
• co19/LanguageFeatures/Patterns/record_A01_t07
• co19/LanguageFeatures/Patterns/record_A01_t08
• co19/LanguageFeatures/Patterns/variable_A02_t01
• co19/LanguageFeatures/Patterns/variable_A02_t03
• co19/LanguageFeatures/Patterns/variable_A02_t04
• co19/LanguageFeatures/Patterns/variable_A02_t06

[chloestefantsova]

One of the tests tracked in this issue fails with a missed compile-time error, and all other pass. I'm closing this issue.