[webkit.NoUncountedMemberChecker] Fix a regression that every class is treated as if it's ref countable. (llvm#131249)

This PR fixes a regression that webkit.NoUncountedMemberChecker and
alpha.webkit.NoUncheckedMemberChecker emits warnings for every class as
if they supported ref counting and checked ptr because we were
erroneously coercing the return value of isRefCountable and
isCheckedPtrCapable, which is std::optional<bool>, to boolean values.

Author: rniwa

clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefMemberChecker.cpp

@@ -224,7 +224,7 @@ class NoUncountedMemberChecker final : public RawPtrRefMemberChecker {
   std::optional<bool>
   isPtrCompatible(const clang::QualType,
                   const clang::CXXRecordDecl *R) const final {
-    return R && isRefCountable(R);
+    return R ? isRefCountable(R) : std::nullopt;
   }
 
   bool isPtrCls(const clang::CXXRecordDecl *R) const final {
@@ -247,7 +247,7 @@ class NoUncheckedPtrMemberChecker final : public RawPtrRefMemberChecker {
   std::optional<bool>
   isPtrCompatible(const clang::QualType,
                   const clang::CXXRecordDecl *R) const final {
-    return R && isCheckedPtrCapable(R);
+    return R ? isCheckedPtrCapable(R) : std::nullopt;
   }
 
   bool isPtrCls(const clang::CXXRecordDecl *R) const final {

clang/test/Analysis/Checkers/WebKit/uncounted-members.cpp

@@ -36,7 +36,6 @@ namespace members {
   };
 }
 
-
 namespace ignore_unions {
   union Foo {
     RefCountable* a;
@@ -60,3 +59,12 @@ void foo(RefCountable* t) {
 }
 
 } // ignore_system_header
+
+namespace ignore_non_ref_countable {
+  struct Foo {
+  };
+
+  struct Bar {
+    Foo* foo;
+  };
+}