Function declarations were previously permitted by V8 in many locations
which no ECMAScript specification allowed; the ECMAScript 2015 spec
enumerates a few locations (in blocks, as well as after labels and in
conditionals when in sloppy mode). This patch ships the flag to restrict
the usage of function declarations to those contexts.
R=adamk
LOG=Y
BUG=v8:4824
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel
Review URL: https://codereview.chromium.org/1799233003
Cr-Commit-Position: refs/heads/master@{#34828}
Clusterfuzz testing discovered that sloppy-mode block-scoped function
declarations introduce lexically-scoped variables in scopes that were
thrown away under the expectation that no lexically-scoped variables
were introduced. These cases are:
for (;;) function foo() {}
for (x in y) function foo() {}
This patch ensures that a block is created in those cases to hold the
lexically scoped variable. Usually, scope analysis should discover that
that block is not important, and it should not have a runtime
representation.
BUG=chromium:536750,chromium:536751
LOG=Y
R=adamk
Review URL: https://codereview.chromium.org/1382123002
Cr-Commit-Position: refs/heads/master@{#31109}
