Implement a sub-group of -Wconversion: -Wliteral-conversion. This
specifically targets literals which are implicitly converted, a those
are more often unintended and trivial to fix. This can be especially
helpful for diagnosing what makes 'const int x = 1e6' not an ICE.

Original patch authored by Jim Meehan with contributions from other
Googlers and a few cleanups from myself.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125745 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed