[libcxx-commits] [libcxx] [libc++][test] Silence MSVC warnings (PR #79791)

[Stephan T. Lavavej via libcxx-commits]

https://github.com/StephanTLavavej created https://github.com/llvm/llvm-project/pull/79791

* `libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp` emits a bunch of warnings, all caused by what appears to be intentional code:
  + Silence MSVC warning C4245: conversion from `'int'` to `'wchar_t'`, signed/unsigned mismatch
    - Caused by: `test<U>(0, -1);`
  + Silence MSVC warning C4305: 'argument': truncation from `'int'` to `'bool'`
    - Caused by: `test<U>(0, -1);`
  + Silence MSVC warning C4310: cast truncates constant value
    - Caused by: `test<U>(T(-129), U(-129));`
  + Silence MSVC warning C4805: `'=='`: unsafe mix of type `'char'` and type `'bool'` in operation
    - Caused by: `bool expect_match = val == to_find;`
* `libcxx/test/std/algorithms/alg.nonmodifying/alg.fold/left_folds.pass.cpp`
  + Silence MSVC warning C4244: 'argument': conversion from `'double'` to `'const int'`, possible loss of data
    - Caused by `[](int const x, double const y) { return x + y; }` deliberately being given `double`s to truncate.
* `libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.pointer.pass.cpp`
  + Silence MSVC warnings about C++20 deprecated `volatile`.
    - Caused by: `runtime_test<      volatile T>();`


>From 8403af2128e06bbd16bd014f577def2c5355f006 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Sun, 28 Jan 2024 22:03:29 -0800
Subject: [PATCH 1/3] Silence MSVC warnings.

* Silence MSVC warning C4245: conversion from 'int' to 'wchar_t', signed/unsigned mismatch
  + Caused by: `test<U>(0, -1);`
* Silence MSVC warning C4305: 'argument': truncation from 'int' to 'bool'
  + Caused by: `test<U>(0, -1);`
* Silence MSVC warning C4310: cast truncates constant value
  + Caused by: `test<U>(T(-129), U(-129));`
* Silence MSVC warning C4805: '==': unsafe mix of type 'char' and type 'bool' in operation
  + Caused by: `bool expect_match = val == to_find;`
---
 .../std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp  | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp
index 0676da13e90f76b..c41246522fdebac 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp
@@ -8,8 +8,12 @@
 
 // ADDITIONAL_COMPILE_FLAGS(gcc): -Wno-bool-compare
 // ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare
+// MSVC warning C4245: conversion from 'int' to 'wchar_t', signed/unsigned mismatch
+// MSVC warning C4305: truncation from 'int' to 'bool'
+// MSVC warning C4310: cast truncates constant value
 // MSVC warning C4389: '==': signed/unsigned mismatch
-// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4389
+// MSVC warning C4805: '==': unsafe mix of type 'char' and type 'bool' in operation
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4245 /wd4305 /wd4310 /wd4389 /wd4805
 
 // <algorithm>
 

>From 3be0afa88e5c577ee110e27d9857575de3542e79 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Sun, 28 Jan 2024 22:26:04 -0800
Subject: [PATCH 2/3] Silence MSVC warnings about C++20 deprecated volatile.

Caused by: `runtime_test<      volatile T>();`
---
 .../numeric.ops.midpoint/midpoint.pointer.pass.cpp           | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.pointer.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.pointer.pass.cpp
index 5138fd6a37469f7..e8a25c174076a62 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.pointer.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.pointer.pass.cpp
@@ -7,6 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// MSVC warning C5215: a function parameter with a volatile qualified type is deprecated in C++20
+// MSVC warning C5216: a volatile qualified return type is deprecated in C++20
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd5215 /wd5216
+
 // <numeric>
 
 // template <class _Tp>

>From 3bedd91fc54e8ef7877f03585b0ff307bde45523 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl at nuwen.net>
Date: Sun, 28 Jan 2024 22:33:30 -0800
Subject: [PATCH 3/3] Silence MSVC warning C4244: 'argument': conversion from
 'double' to 'const int', possible loss of data

Caused by `[](int const x, double const y) { return x + y; }` deliberately being given doubles to truncate.
---
 .../algorithms/alg.nonmodifying/alg.fold/left_folds.pass.cpp   | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.fold/left_folds.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.fold/left_folds.pass.cpp
index cf089b27c76e029..b8da26a229fa995 100644
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.fold/left_folds.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.fold/left_folds.pass.cpp
@@ -10,6 +10,9 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
+// MSVC warning C4244: 'argument': conversion from 'double' to 'const int', possible loss of data
+// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4244
+
 // template<input_iterator I, sentinel_for<I> S, class T,
 //          indirectly-binary-left-foldable<T, I> F>
 //   constexpr see below ranges::fold_left_with_iter(I first, S last, T init, F f);