Before: Kernel static errors were represented by throwing a distinguished
error or else by calling a distinguished library const constructor.
Now: Kernel static errors are represented by InvalidExpression. To support
error reporting, InvalidExpression has an optional message and a file
offset. A back end can choose to signal these errors at any time; for
example, when deserializing the binary, or when compiling the procedure
containing the static error, or when the erroneous expression is evaluated
at run time.
InvalidStatement is removed because it can be encoded as ExpressionStatement
of InvalidExpression.
Future work:
* supporting static errors where an expression cannot appear in the AST
* allowing InvalidExpression to contain an Expression for error recovery
* adding a top-level list of static errors and warnings to the binary
Bug: https://github.com/dart-lang/sdk/issues/29840
Change-Id: Ifdfe9a76cee6cefed28061bf245be70531d2f413
Reviewed-on: https://dart-review.googlesource.com/31320
Commit-Queue: Kevin Millikin <kmillikin@google.com>
Reviewed-by: Dan Rubel <danrubel@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Kevin Millikin
6fa813d818