ES2015 specifies very particular semantics for functions defined in blocks.
In strict mode, it is simply a lexical binding scoped to that block. In sloppy
mode, in addition to that lexical binding, there is a var-style binding in
the outer scope, which is overwritten with the local binding when the function
declaration is evaluated, *as long as* introducing ths var binding would not
create a var/let conflict in the outer scope.
This patch implements the semantics by introducing a DelegateStatement, which
is initially filled in with the EmptyStatement and overwritten with the
assignment when the scope is closed out and it can be checked that there is
no conflict.
This patch is tested with a new mjsunit test, and I tried staging it and running
test262, finding that the tests that we have disabled due to lack of Annex B
support now pass.
R=adamk,rossberg
LOG=Y
BUG=v8:4285
Review URL: https://codereview.chromium.org/1332873003
Cr-Commit-Position: refs/heads/master@{#30842}
This patch strengthens testing of classes by verifying that the binding
that they export externally follows block scoping, as opposed to var-style
scoping. The tests are based on existing tests for let and const.
R=adamk
LOG=N
BUG=v8:3305
Review URL: https://codereview.chromium.org/1286923002
Cr-Commit-Position: refs/heads/master@{#30140}
In an initial attempt to implement sloppy mode lexical bindings,
functions were made lexically scoped in sloppy mode. However, the
ES2015 spec says that they need an additional hoisted var binding,
and further, it's not clear when we'll implement that behavior
or whether it's web-compatible.
This patch splits off function block scoping into a new, separate
flag called --harmony_sloppy_function. This change will enable the
possibility of testing and shipping this feature separately from
other block scoping-related features which don't have the same risks.
BUG=v8:4285
R=adamk
LOG=N
Review URL: https://codereview.chromium.org/1282093002
Cr-Commit-Position: refs/heads/master@{#30122}
--harmony_sloppy includes behavior to turn on sloppy mode lexical
bindings. Before this patch, it also included a way to parse let
which is likely web-incompatible (let is disallowed as an
identifier). This patch splits off the let parsing from the more
general block scoping code, so that block scoping can be developed
independently.
R=adamk
LOG=N
BUG=v8:3305
Review URL: https://codereview.chromium.org/1255013002
Cr-Commit-Position: refs/heads/master@{#29855}
