[libc][NFC] Fix accessor qualifiers for cpp::expected

[gchatelet]

No description provided.

[llvmbot]

@llvm/pr-subscribers-libc

Author: Guillaume Chatelet (gchatelet)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/80424.diff

1 Files Affected:

• (modified) libc/src/__support/CPP/expected.h (+5-3)

diff --git a/libc/src/__support/CPP/expected.h b/libc/src/__support/CPP/expected.h
index 52174a054f874..100abfc221161 100644
--- a/libc/src/__support/CPP/expected.h
+++ b/libc/src/__support/CPP/expected.h
@@ -33,10 +33,12 @@ template <class T, class E> class expected {
   constexpr expected(unexpected<E> unexp)
       : unexp(unexp.error()), is_expected(false) {}
 
-  constexpr bool has_value() { return is_expected; }
+  constexpr bool has_value() const { return is_expected; }
 
-  constexpr T value() { return exp; }
-  constexpr E error() { return unexp; }
+  constexpr T &value() { return exp; }
+  constexpr E &error() { return unexp; }
+  constexpr const T &value() const { return exp; }
+  constexpr const E &error() const { return unexp; }
 
   constexpr operator bool() { return is_expected; }