Previously, the migration tool had a small amount of special case
logic in `EdgeBuilder._dispatch` to ensure that if an `as`
expression's type was annotated with `/*!*/`, that `/*!*/` wouldn't be
misinterpreted as also applying to the `as` expression itself (causing
a `!` operator to be inserted). This logic wasn't sufficiently
general; it failed to handle `is` expressions (which can run into the
same issue), and it failed to handle situations where the `is` or `as`
expression was at the end of a larger expression (e.g. `y = x as
T/*!*/;`).
This change removes the special case logic and replaces it with a more
general-purpose mechanism: when visiting any type name, if it ends in
a `/*!*/`, the edge builder stores information about it in the
`_nullCheckHints` field. This ensures that when visiting an
expression ending in that type name, the `/*!*/` will be ignored
(since `EdgeBuilder._handleNullCheckHint` skips any hints that are
already stored in that field). This ensures that we properly handle
both `is` and `as` expressions, as well as larger expressions that
contain them.
Change-Id: I2b902ef809b4cc5eb8b493fa4405c0f0c8c10a96
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/202261
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
Paul Berry
9a83a75a10