swift234

[Sema] Add source location for synthesized designated initializer overrides.

When synthesizing designated initializer overrides, set the source location
for the synthesized ConstructorDecl to the location of the opening brace of
the containing ClassDecl. This resolves an assertion failure when constructing
type refinement contexts when whole-program optimization is turned on.

rdar://problem/21233342

Swift SVN r29384