[boost] [config] Proposed new defect macro : BOOST_NO_IMPLICIT_BOOL_CONVERSION

From: AlisdairM (alisdair.meredith_at_[hidden])
Date: 2007-06-05 08:28:48

Attached is the test file for a proposed new defect macro,
BOOST_NO_IMPLICIT_BOOL_CONVERSION.

This identifies compilers (such as Borland) that do not always convert
expressions to bool as required by 5.14/5.15 and elsewhere.  The
workaround is fairly simple - detect the bad compiler and add an
additional static_cast<bool>( ) around the (sub)expression.

This only really catches classes relying on the
convertible-to-unspecified-bool-type idiom.

The test results I am posting have applied this workaround in a number
of places, and obviously I would prefer to post those patches with a
defect macro rather than compiler (and version) specific workarounds.

Note: the tests checks all 'boolean contexts', not just the two or
three that fail with Borland.  I don't know if this will catch any
other compilers.

As ever, I am open to suggestions for a better name.

-- 
AlisdairM