AK: Verify that m_impl is non-null in String::operator[]

This helps to find bugs where null strings are indexed into with
operator[], as this would previously only report a RefPtr null
dereference.

1 files changed, 1 insertions, 0 deletions

diff --git a/AK/String.h b/AK/String.h
index 56ef416200..c6e6e468b4 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -160,6 +160,7 @@ public:
 
     [[nodiscard]] ALWAYS_INLINE const char& operator[](size_t i) const
     {
+        VERIFY(!is_null());
         return (*m_impl)[i];
     }