commit e680c988816ac49c410b2f2ea01c163f627dd8ef
author Johnni Winther <johnniwinther@google.com> Wed Mar 15 19:17:48 2023 +0000
committer Commit Queue <dart-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Mar 15 19:17:48 2023 +0000
tree b7378e8fd728102c43c729e9eb3ee269ab3f9dfe
parent aab39d39389bf2348b06d5eb27eda26594785840

[_fe_shared_analyzer] Pass context type when creating spaces from patterns

This passes the [StaticType] for the context of a pattern to the
pattern converter. This is used to restrict the static type of the
created space. For instance when creating the space for an untyped
wildcard pattern, the context type will be used instead of the
nullable-object (top) type. For other patterns, if the context type
is a subtype of the type for the pattern itself, the context type
will be used instead.

This has the benefit that when checking for unreachable cases we will
not take a too broad case to mean that it has some that it could match.
For instance in `Foo(:var hashCode)` the space for `var hashCode` would
have been the nullable-object type, and if the preceeding case was
`Foo(:int hashCode)`, the reachable check would fail to see that all
cases are covered since nullable-object is not a subtype of int.

With this change, such cases are now handled.

Change-Id: I5b6248bf79c8cf0b365eee2f3ca78090c3f43512
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/288902
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>