Handle nil with any number of parentheses

Author: HassanElDesouky

lib/Sema/CSGen.cpp

@@ -1152,7 +1152,11 @@ namespace {
       // `_ = nil`, let's diagnose it here because solver can't
       // attempt any types for it.
       auto *parentExpr = CS.getParentExpr(expr);
-      if (parentExpr && isa<ParenExpr>(parentExpr))
+      
+      // Loop until you have an expr without parentheses 
+      // so if you have (nil), ((nil)), (((nil))), etc...
+      // you get `nil`
+      while (parentExpr && isa<ParenExpr>(parentExpr))
         parentExpr = CS.getParentExpr(parentExpr);
 
       if (parentExpr) {