libstdc++: Fix PSTL test that fails in C++20

This test fails in C++20 and later due to a warning:

warning: C++20 says that these are ambiguous, even though the second is reversed:
note: candidate 1: 'bool MyClass::operator==(const MyClass&)'
note: candidate 2: 'bool MyClass::operator==(const MyClass&)' (reversed)
note: try making the operator a 'const' member function
FAIL: 26_numerics/pstl/numeric_ops/transform_reduce.cc (test for excess errors)

libstdc++-v3/ChangeLog:

	* testsuite/26_numerics/pstl/numeric_ops/transform_reduce.cc:
	Add const to equality operator.

(cherry picked from commit f8403c43045cd56b5f775e1cf12a3f22feca4b58)

diff --git a/libstdc++-v3/testsuite/26_numerics/pstl/numeric_ops/transform_reduce.cc b/libstdc++-v3/testsuite/26_numerics/pstl/numeric_ops/transform_reduce.cc
index ec020b42bbb4246336173a6055167220e997169c..bec1c14127884bbe18461e972f7d2a825deae290 100644 (file)
--- a/libstdc++-v3/testsuite/26_numerics/pstl/numeric_ops/transform_reduce.cc
+++ b/libstdc++-v3/testsuite/26_numerics/pstl/numeric_ops/transform_reduce.cc
@@ -68,7 +68,7 @@ class MyClass
     }
     friend MyClass operator*(const MyClass& x, const MyClass& y) { return MyClass(x.my_field * y.my_field); }
     bool
-    operator==(const MyClass& in)
+    operator==(const MyClass& in) const
     {
         return my_field == in.my_field;
     }