Previously the "as" keyword could either represent coercion or or forced
downcasting. This change separates the two notions. "as" now only means
type conversion, while the new "as!" operator is used to perform forced
downcasting. If a program uses "as" where "as!" is called for, we emit a
diagnostic and fixit.
Internally, this change removes the UnresolvedCheckedCastExpr class, in
favor of directly instantiating CoerceExpr when parsing the "as"
operator, and ForcedCheckedCastExpr when parsing the "as!" operator.
Swift SVN r24253
This commit decouples StdlibUnittest from many details of
[Contiguous]Array, so tests can give useful feedback even in the
presence of a broken [Contiguous]Array implementation while we refactor.
Unfortunately, it wasn't practical to make _UnitTestArray use a
storage class other than _ContiguousArrayStorage[Base], so we still have
to watch out when making changes there.
Swift SVN r22875
ContiguousArray is a simpler component, thus less prone to breakage.
Builting the unit testing framework atop broken components is a very bad
idea, so let's not.
This is a reinstatement of an earlier commit, plus changes to make the
validation tests work.
Swift SVN r22867
The previous version of this test was disallowing some thread
interleavings that I did not consider. See comments in the test for
more details.
Swift SVN r22300
