diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h b/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.h
@@ -37,6 +37,9 @@
 
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  std::optional<TraversalKind> getCheckTraversalKind() const override {
+    return TK_IgnoreUnlessSpelledInSource;
+  }
 
 private:
   bool handleDeletion(const ast_matchers::BoundNodes &Nodes);
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -330,6 +330,10 @@
   to emit warnings only on classes that are copyable/movable, as required by the
   corresponding rule.
 
+- Improved :doc:`cppcoreguidelines-owning-memory
+  <clang-tidy/checks/cppcoreguidelines/owning-memory>` check now finds more
+  issues, especially those related to implicit casts.
+
 - Deprecated C.48 enforcement from :doc:`cppcoreguidelines-prefer-member-initializer
   <clang-tidy/checks/cppcoreguidelines/prefer-member-initializer>`. Please use
   :doc:`cppcoreguidelines-use-default-member-init
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/owning-memory.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/owning-memory.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/owning-memory.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/owning-memory.cpp
@@ -382,3 +382,16 @@
   template_function(IntOwner1);  // Ok, but not actually ok, since type deduction removes owner
   template_function(stack_ptr1); // Bad, but type deduction gets it wrong
 }
+
+namespace PR63994 {
+  struct A {
+    virtual ~A() {}
+  };
+
+  struct B : public A {};
+
+  A* foo(int x) {
+    return new B;
+    // CHECK-NOTES: [[@LINE-1]]:5: warning: returning a newly created resource of type 'A *' or 'gsl::owner<>' from a function whose return type is not 'gsl::owner<>'
+  }
+}