Sema: Handle CGFloat <-> Double conversion in getOptionalEvaluationDepth()

Author: slavapestov

lib/Sema/CSApply.cpp

@@ -5868,6 +5868,9 @@ static unsigned getOptionalEvaluationDepth(Expr *expr, Expr *target) {
       depth += getOptionalEvaluationDepth(open->getSubExpr(),
                                           open->getOpaqueValue());
       expr = open->getExistentialValue();
+    } else if (auto call = dyn_cast<CallExpr>(expr)) {
+      // CGFloat <-> Double conversions lower to constructor calls.
+      expr = call->getArgs()->getExpr(0);
 
     // Otherwise, look through implicit conversions.
     } else {