Bug 1514801 - refactor clang based checker - KungFuDeathGripChecker. r=glandium

Differential Revision: https://phabricator.services.mozilla.com/D38187

--HG--
extra : moz-landing-system : lando

build/clang-plugin/KungFuDeathGripChecker.cpp

@@ -6,7 +6,11 @@
 #include "CustomMatchers.h"
 
 void KungFuDeathGripChecker::registerMatchers(MatchFinder *AstMatcher) {
-  AstMatcher->addMatcher(varDecl(hasType(isRefPtr())).bind("decl"), this);
+  AstMatcher->addMatcher(varDecl(allOf(hasType(isRefPtr()),
+                                       hasLocalStorage(),
+                                       hasInitializer(anything())))
+                             .bind("decl"),
+                         this);
 }
 
 void KungFuDeathGripChecker::check(const MatchFinder::MatchResult &Result) {
@@ -16,7 +20,7 @@ void KungFuDeathGripChecker::check(const MatchFinder::MatchResult &Result) {
                      "'%1', or explicitly pass '%1' to `mozilla::Unused`";
 
   const VarDecl *D = Result.Nodes.getNodeAs<VarDecl>("decl");
-  if (D->isReferenced() || !D->hasLocalStorage() || !D->hasInit()) {
+  if (D->isReferenced()) {
     return;
   }
 
@@ -44,6 +48,12 @@ void KungFuDeathGripChecker::check(const MatchFinder::MatchResult &Result) {
     E = IgnoreTrivials(CE->getArg(0));
   }
 
+  // It is possible that the QualType doesn't point to a type yet so we are
+  // not interested.
+  if (E->getType().isNull()) {
+    return;
+  }
+
   // We allow taking a kungFuDeathGrip of `this` because it cannot change
   // beneath us, so calling directly through `this` is OK. This is the same
   // for local variable declarations.