[libcxx-commits] [PATCH] D117089: [libc++] Quick fix to remove a narrowing conversion from the in_out_result test.

[Konstantin Varlamov via Phabricator via libcxx-commits]

var-const created this revision.
var-const requested review of this revision.
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This needs a proper solution in a follow-up. The issue is that the
Standard defines conversions between `in_out_result` classes with
different template types as just `return {in, out};`. Because the
expression uses list initialization, it will fail to compile if the
conversion happens to be narrowing -- which is probably unintended.

Surprisingly, this error wasn't caught by the CI.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D117089

Files:
  libcxx/test/std/algorithms/algorithms.results/in_out_result.pass.cpp


Index: libcxx/test/std/algorithms/algorithms.results/in_out_result.pass.cpp
===================================================================
--- libcxx/test/std/algorithms/algorithms.results/in_out_result.pass.cpp
+++ libcxx/test/std/algorithms/algorithms.results/in_out_result.pass.cpp
@@ -53,8 +53,9 @@
   // Conversion, fundamental types.
   {
     std::ranges::in_out_result<int, bool> x = {2, false};
-    std::ranges::in_out_result<double, char> y = x;
-    assert(y.in == 2.0);
+    // FIXME(varconst): try a narrowing conversion.
+    std::ranges::in_out_result<long, char> y = x;
+    assert(y.in == 2);
     assert(y.out == '\0');
   }
 
@@ -138,4 +139,3 @@
 
   return 0;
 }
-


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