When the parser sends events to the listener some events has a pair of
parameters, `beginToken` and `endToken`. Most of these are constructed
in such a way that the `beginToken` is the first token and the
`endToken` is the last token in that construct. This is for instance the
case with `endClassDeclaration`.
It was, however, not the case for `endMetadata` where `endToken` instead
was the next token *not* in the metadata.
In this CL I've found a changed the following to point to the last token
in the construct instead of the next token not in the construct and
renamed the parameter where it made sense:
* `endAssert` --- and renamed `semicolonToken` (which only pointed to
a semicolon for statements) to `endToken`.
* `endAwaitExpression`
* `endConstLiteral` --- and renamed `token` to `endToken`
* `endConstructorReference`
* `endFieldInitializer` --- and renamed `token` to `endToken`
* `endForIn`
* `endForInBody` --- and renamed `token` to `endToken`
* `endForStatement`
* `endForStatementBody` --- and renamed `token` to `endToken`
* `endFunctionExpression` --- and renamed `token` to `endToken`
* `endInitializer` --- and renamed `token` to `endToken`
* `endInitializers`
* `endInvalidAwaitExpression`
* `endMetadata`
* `endSwitchCase`
* `endTopLevelDeclaration` --- and renamed `nextToken` to `endToken`
* `endWhileStatement`
* `endWhileStatementBody` --- and renamed `token` to `endToken`
* `handleNoConstructorReferenceContinuationAfterTypeArguments`
In the few places in listeners where these values were used I've mostly
updated to do e.g. `endToken.text!` to retain the current behavior.
Change-Id: I25495e160d1eec5c75bcf1313b512cd04bcb1533
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/364322
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
This change fixes parsing of case clauses such as:
case foo when !flag:
Constructions like this require some lookahead in order to parse
correctly, because the token `when` is valid both as an identifier and
as a part of the grammar for a case clause. Therefore, at the time
`foo` is encountered, the parser must decide whether it is looking at
a variable pattern (`foo when`, where `when` is the name of the
variable) or an identifier pattern (`foo`, where `when` begins the
case's guard clause). Previous to this fix, the algorithm for
disambiguating these two choices was as follows:
- If the token sequence starting at `foo` looked like a type, and the
token that follows was an identifier, the parser assumed it was
looking at a variable pattern with a type; otherwise it assumed it
was looking at an identifier pattern.
- EXCEPT that if the token that followed the supposed type was `when`
or `as` (both of which are valid identifiers), then it probed
further:
- If the token that followed `when` or `as` was a token that could
legitimately follow a pattern, then it assumed that it was looking
at a variable pattern with a type. (The tokens that could
legitimately follow a pattern are `,`, `:`, `||`, `&&`, `)`, `}`,
`]`, `as`, `when`, `?`, `!`).
- Otherwise it assumed that it was looking at an identifier pattern.
This didn't fully disambiguate, because the third bullet didn't
account for the fact that the tokens `as`, `when`, and `!` could
_either_ legitimately follow a pattern _or_ legitimately begin an
expression (or, in the case of `when`, a type), therefore constructs
like the following were incorrectly parsed:
- `case foo when as:` (where `as` is a local boolean variable)
- `case foo when when:` (where `when` is a local boolean variable)
- `case foo when !flag:` (where `flag` is a local boolean variable)
- `case foo as when:` (where `when` is the name of a type)
The solution is to simplify the disambiguation logic so that if if the
token that follows the supposed type is `when` or `as`, then the
parser assumes that it's looking at an identifier pattern, _not_ a
typed variable pattern.
The consequence of this is that the above four constructions are
parsed correctly; however it is no longer possible for a typed
variable pattern to name a variable `when` or `as`.
For consistency we would like to prohibit _any_ variable pattern from
naming a variable `when` or `as`, however to keep this change as small
as possible (and reduce the risk involved in a possible cherry-pick)
that will be postponed until a later CL.
Fixes#52199.
Bug: https://github.com/dart-lang/sdk/issues/52199
Change-Id: Ibab9b92f01e3e4020d7d64f1ff000a9b964a4564
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/299400
Commit-Queue: Paul Berry <paulberry@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Jens Johansen <jensj@google.com>
Jens Johansen