This is a reland of 1fba044154
Chromium expectation tests have been disabled, and will be enabled
Original change's description:
> [destructuring] Elide coercible check for simple keys
>
> Simple object destructuring, such as `let {a,b} = o`, is less efficient
> than the equivalent assignments `let a = o.a; let b = o.b`. This is
> because it does a nil check of `o` before the assignments. However, this
> nil check is not strictly necessary for simple (i.e. non-computed) names,
> as there will be an equivalent nil check on the first access to o in
> `o.a`. For computed names the computation is unfortunately obervable.
>
> So, we can elide the nil check when the first property (if any) of the
> destructuring target is a non-computed name. This messes a bit with our
> error messages, so we re-use the CallPrinter to also find destructuring
> assignment based errors, and fiddle with the error message there. As
> a side-effect, we also get out the object name in the AST, so we can
> output a slightly nicer error message.
>
> Change-Id: Iafa858e27ed771a146cd3ba57903cc73bb46951d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1773254
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63453}
TBR=verwaest@chromium.org
Bug: chromium:999473
Change-Id: Ib0b2e4be433c50521ba1722e1c06b672bfefa405
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1777702
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63477}
Tests in test/message pass if the output matches the expected output.
Message tests are particularly useful when checking for exact error messages.
Tests and their expected output must have the same filename, with the .js and
.out extension.
foo.js
foo.out
All tests must end with an exception. The test runner does not
handle output from multiple runs, e.g., --stress-opt. Without an exception,
the output will be generated several times and the comparison will fail.
You can use a regex in the expected output instead of the exact
path:
*%(basename)s:7: SyntaxError: Detected cycle while resolving name 'a'
Empty lines are ignored in the comparison, but whitespaces are not.
Exact details of the test runner are in testcfg.py.
ef2df57aa5