[clang] [clang-tidy] [dataflow] Cache reference accessors for `bugprone-unchecked-optional-access` (PR #128437)

[Valentyn Yukhymenko via cfe-commits]

================
@@ -3863,6 +3863,192 @@ TEST_P(UncheckedOptionalAccessTest, ConstBoolAccessorWithModInBetween) {
   )cc");
 }
 
+TEST_P(UncheckedOptionalAccessTest,
+       ConstRefAccessorToOptionalViaConstRefAccessorToHoldingObject) {
+  ExpectDiagnosticsFor(R"cc(
+    #include "unchecked_optional_access_test.h"
+
+    class A {
+      public:
+        const $ns::$optional<int>& get() const { return x; }
+      
+      private:
+        $ns::$optional<int> x;
+    };
+
+    class B {
+      public:
+        const A& getA() const { return a; }
+    
+      private:
+        A a;
+    };
+
+    void target(B& b) {
+      if (b.getA().get().has_value()) {
+        b.getA().get().value();
+      }
+    }
+  )cc");
+}
+
+TEST_P(
+    UncheckedOptionalAccessTest,
+    ConstRefAccessorToOptionalViaConstRefAccessorToHoldingObjectWithoutValueCheck) {
+  ExpectDiagnosticsFor(R"cc(
+    #include "unchecked_optional_access_test.h"
+
+    class A {
+      public:
+        const $ns::$optional<int>& get() const { return x; }
+      
+      private:
+        $ns::$optional<int> x;
+    };
+
+    class B {
+      public:
+        const A& getA() const { return a; }
+    
+      private:
+        A a;
+    };
+
+    void target(B& b) {
+      b.getA().get().value(); // [[unsafe]]
+    }
+  )cc");
+}
+
+TEST_P(UncheckedOptionalAccessTest,
+       ConstRefToOptionalSavedAsTemporaryVariable) {
----------------
BaLiKfromUA wrote:

added this test to check that the existing workaround still works. maybe redundant test

https://github.com/llvm/llvm-project/pull/128437