Commits

Joe Groff committed 3b0180b1b02
Allow '_' in assignments again. Parse '_' as a DiscardAssignmentExpr. Type-check it as an lvalue, and check that it only appears in the LHS of AssignExprs. During matching pattern resolution, convert it into an AnyPattern. In SILGen, when we see '_' in the LHS of an assignment, ignore the corresponding RHS rvalue. Swift SVN r8848