[FIX] libc++: header tests

.github/workflows/ci_misc.yml

@@ -43,6 +43,13 @@ jobs:
             build_type: Release
             test_threads: 2
 
+          - name: "Header clang17 libc++"
+            compiler: "clang-17"
+            build: header
+            build_type: Release
+            test_threads: 2
+            cxx_flags: "-stdlib=libc++"
+
           - name: "Header gcc13"
             compiler: "gcc-13"
             build: header

include/seqan3/core/debug_stream/debug_stream_type.hpp

@@ -155,7 +155,7 @@ class debug_stream_type
     //!\}
 
     //!\brief This type is std::ios_base::fmtflags
-    using fmtflags = decltype(std::declval<std::basic_ostream<char_t>>().flags());
+    using fmtflags = typename std::basic_ostream<char_t>::fmtflags;
 
     /*!\name Format flags (std::ios_base::fmtflags)
      * \brief std::ios_base::fmtflags that modify the stream's behaviour.

include/seqan3/utility/simd/detail/builtin_simd.hpp

@@ -134,7 +134,7 @@ constexpr bool is_builtin_simd_v = is_builtin_simd<builtin_simd_t>::value;
  * seqan3::detail::builtin_simd types.
  */
 template <>
-constexpr auto default_simd_max_length<builtin_simd> = []()
+inline constexpr auto default_simd_max_length<builtin_simd> = []()
 {
 #if defined(__AVX512F__)
     return min_viable_uint_v<64u>;

test/header/CMakeLists.txt

@@ -84,7 +84,7 @@ macro (seqan3_header_test component header_base_path exclude_regex)
 
     file (WRITE "${PROJECT_BINARY_DIR}/${target}.cpp" "")
     add_executable (${target} ${PROJECT_BINARY_DIR}/${target}.cpp)
-    target_link_libraries (${target} seqan3::test::header)
+    target_link_libraries (${target} seqan3::test seqan3::test::header)
     add_test (NAME "header/${target}" COMMAND ${target})
 
     foreach (header ${header_files})
@@ -112,7 +112,10 @@ macro (seqan3_header_test component header_base_path exclude_regex)
                                         "${CMAKE_CURRENT_SOURCE_DIR}/generate_header_source.cmake")
 
             add_library (${header_target} OBJECT "${header_target_source}")
-            target_link_libraries (${header_target} seqan3::test::header)
+            # Link seqan3::test first, even though it is also linked by seqan3::test:header.
+            # Without this, the compile options of seqan3::test are appended, e.g.,
+            # `-Wno-error=... -Werror -Wall`, instead of `-Werror -Wall -Wno-error=...`
+            target_link_libraries (${header_target} seqan3::test seqan3::test::header)
             target_sources (${target} PRIVATE $<TARGET_OBJECTS:${header_target}>)
         endforeach ()
     endforeach ()

test/include/seqan3/test/pretty_printing.hpp

@@ -14,6 +14,7 @@
 
 #include <ios>
 #include <iterator>
+#include <ostream>
 
 #include <seqan3/core/debug_stream/debug_stream_type.hpp>
 

test/seqan3-test.cmake

@@ -120,6 +120,8 @@ if (NOT TARGET seqan3::test::header)
     add_library (seqan3_test_header INTERFACE)
     target_link_libraries (seqan3_test_header INTERFACE "seqan3::test::unit")
     target_link_libraries (seqan3_test_header INTERFACE "seqan3::test::performance")
+    target_compile_options (seqan3_test_header INTERFACE "-Wno-unused-const-variable" "-Wno-unused-variable"
+                                                         "-Wno-unused-function")
     target_compile_definitions (seqan3_test_header INTERFACE -DSEQAN3_DISABLE_DEPRECATED_WARNINGS)
     target_compile_definitions (seqan3_test_header INTERFACE -DSEQAN3_HEADER_TEST)
     add_library (seqan3::test::header ALIAS seqan3_test_header)