[analyzer] Use IgnoreImpCasts() instead of reimplementing it.

[thakis]

Summary

No intended behavior change.

[Charusso]

clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp

512

I think it would make sense to remove the helper-function completely. (Being used 2 times.)

[NoQ]

Fair!

clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp

512

Yup.

[thakis]

clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp

512

I didn't do that because I liked the comment that this is for the _Nonnull implicit ARC casts – if I inline the function I have to duplicate the comment.

[Charusso]

clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp

512

Well, if you really like that, sure. I believe it is so common to avoid implicit casts we do not need to express it why.

clang/lib/StaticAnalyzer/Checkers/NullabilityChecker.cpp

void NullabilityChecker::checkEvent(ImplicitNullDerefEvent Event) const {
   }
 }
 
 /// Find the outermost subexpression of E that is not an implicit cast.
 /// This looks through the implicit casts to _Nonnull that ARC adds to
 /// return expressions of ObjC types when the return type of the function or
 /// method is non-null but the express is not.
 static const Expr *lookThroughImplicitCasts(const Expr *E) {
-  assert(E);
-
-  while (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) {
-    E = ICE->getSubExpr();
-  }
-
-  return E;
+  return E->IgnoreImpCasts();
 }
 
 /// This method check when nullable pointer or null value is returned from a
 /// function that has nonnull return type.
 void NullabilityChecker::checkPreStmt(const ReturnStmt *S,
                                       CheckerContext &C) const {
   auto RetExpr = S->getRetValue();
   if (!RetExpr)
     return;