swift

42957c58 - [DebugInfo][SILGen] Ensure "guard let" is lowered with a non-implicit location

[DebugInfo][SILGen] Ensure "guard let" is lowered with a non-implicit location Prior to this patch, a "guard let" was being lowered with an implicit debug location, causing it to be dropped in later stages of the compiler, and making it impossible to set a breakpoint in that line. This was tracked down to a piece of code in `SILGenFunction::emitExprInto`, which takes an optional Location parameter that was being ignored in one code path. (cherry picked from commit 8baf9331140b3a9ce94835ee7f899e3846e90659)