swift234

Allow inout closure param type to be inferred from context or usage.

Introduce a new constraint kind, BindParam, which relates the type of a
function parameter to the type of a reference to it from within the
function body. If the param type is an inout type, the ref type is an
lvalue type with the same underlying object type; otherwise the two
types must be the same. This prevents DeclRefExprs from being inferred
to have inout type in some cases.

<rdar://problem/15998821> Fail to infer types for closure that takes an inout argument

Swift SVN r32183