Compiler bug workaround for using format() in a user-defined module

stl/inc/format

@@ -2632,16 +2632,16 @@ template <integral _Integral>
 _NODISCARD constexpr string_view _Get_integral_prefix(const char _Type, const _Integral _Value) noexcept {
     switch (_Type) {
     case 'b':
-        return "0b"sv;
+        return string_view{"0b", 2}; // TRANSITION, VSO-1775715 (should use UDLs in this function)
     case 'B':
-        return "0B"sv;
+        return string_view{"0B", 2};
     case 'x':
-        return "0x"sv;
+        return string_view{"0x", 2};
     case 'X':
-        return "0X"sv;
+        return string_view{"0X", 2};
     case 'o':
         if (_Value != _Integral{0}) {
-            return "0"sv;
+            return string_view{"0", 1};
         }
         return {};
     default:

tests/std/test.lst

@@ -762,5 +762,6 @@ tests\VSO_0849827_multicontainer_emplace_hint_position
 tests\VSO_0938757_attribute_order
 tests\VSO_0961751_hash_range_erase
 tests\VSO_0971246_legacy_await_headers
+tests\VSO_1775715_user_defined_modules
 tests\VSO_1804139_static_analysis_warning_with_single_element_array
 tests\VSO_1925201_iter_traits

tests/std/tests/P2465R3_standard_library_modules/env.lst

@@ -1,20 +1,4 @@
 # Copyright (c) Microsoft Corporation.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-RUNALL_INCLUDE ..\..\..\universal_prefix.lst
-RUNALL_CROSSLIST
-*	PM_CL="/w14365 /D_ENFORCE_FACET_SPECIALIZATIONS=1 /D_STL_CALL_ABORT_INSTEAD_OF_INVALID_PARAMETER /Zc:preprocessor"
-RUNALL_CROSSLIST
-*	PM_CL="/w14640 /Zc:threadSafeInit- /EHsc /DTEST_STANDARD=20 /std:c++20"
-*	PM_CL="/w14640 /Zc:threadSafeInit- /EHsc /DTEST_STANDARD=23 /std:c++latest"
-RUNALL_CROSSLIST
-*	PM_CL="/MD"
-*	PM_CL="/MDd"
-*	PM_CL="/MT"
-*	PM_CL="/MTd"
-*	PM_CL="/MDd /analyze:only /analyze:autolog-"
-*	PM_CL="/MDd /GR- /D_HAS_STATIC_RTTI=0"
-*	PM_CL="/MDd /utf-8"
-RUNALL_CROSSLIST
-PM_CL=""
-ASAN	PM_CL="-fsanitize=address /Zi" PM_LINK="/debug"
+RUNALL_INCLUDE ..\modules_20_matrix.lst

tests/std/tests/VSO_1775715_user_defined_modules/__init__.py

@@ -0,0 +1,2 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

tests/std/tests/VSO_1775715_user_defined_modules/custom_format.py

@@ -0,0 +1,29 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+import os
+
+from stl.test.format import STLTestFormat, TestStep
+from stl.test.tests import TestType
+
+
+class CustomTestFormat(STLTestFormat):
+    def getBuildSteps(self, test, litConfig, shared):
+        _, outputBase = test.getTempPaths()
+
+        testCpp = test.getSourcePath()
+        sourceDir = os.path.dirname(testCpp)
+        userIxx = os.path.join(sourceDir, 'user.ixx')
+
+        # Dependency order is important here:
+        inputPaths = [userIxx, testCpp]
+
+        cmd = [test.cxx, *inputPaths, *test.flags, *test.compileFlags]
+
+        if TestType.COMPILE in test.testType:
+            cmd += ['/c']
+        elif TestType.RUN in test.testType:
+            shared.execFile = f'{outputBase}.exe'
+            cmd += [f'/Fe{shared.execFile}', '/link', *test.linkFlags]
+
+        yield TestStep(cmd, shared.execDir, shared.env, False)

tests/std/tests/VSO_1775715_user_defined_modules/custombuild.pl

@@ -0,0 +1,18 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+use strict;
+use warnings;
+
+use Run;
+
+sub CustomBuildHook()
+{
+    my $cwd = Run::GetCWDName();
+
+    # Dependency order is important here:
+    my @inputPaths = ("user.ixx", "test.cpp");
+
+    Run::ExecuteCL(join(" ", @inputPaths, "/Fe$cwd.exe"));
+}
+1

tests/std/tests/VSO_1775715_user_defined_modules/env.lst

@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\modules_20_matrix.lst

tests/std/tests/VSO_1775715_user_defined_modules/lit.local.cfg

@@ -0,0 +1,9 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+import os
+import site
+site.addsitedir(os.path.dirname(os.path.dirname(__file__)))
+import VSO_1775715_user_defined_modules.custom_format
+
+config.test_format = VSO_1775715_user_defined_modules.custom_format.CustomTestFormat()

tests/std/tests/VSO_1775715_user_defined_modules/test.cpp

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// Note: To properly test the fix for VSO-1775715, don't include any headers here.
+
+import User;
+
+int main() {
+    user::prepare_test_environment();
+    user::test_vso_1775715(0, "0 0 0b0 0B0 0x0 0X0 0");
+    user::test_vso_1775715(77, "77 77 0b1001101 0B1001101 0x4d 0X4D 0115");
+}

tests/std/tests/VSO_1775715_user_defined_modules/user.ixx

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+module;
+
+#include <cassert>
+#include <format>
+#include <string>
+
+#include <force_include.hpp>
+
+export module User;
+
+namespace user {
+    export void prepare_test_environment() {
+        assert(test_environment_preparer.succeeded());
+    }
+
+    // DevCom-10313766 VSO-1775715 "Using std::format in a module
+    // requires including <format> header in .cpp files using that module"
+    export template <class T>
+    void test_vso_1775715(const T& value, const char* const expected_str) {
+        const std::string actual_str = std::format("{0:#} {0:#d} {0:#b} {0:#B} {0:#x} {0:#X} {0:#o}", value);
+        assert(actual_str == expected_str);
+    }
+} // namespace user

tests/std/tests/modules_20_matrix.lst

@@ -0,0 +1,20 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\..\universal_prefix.lst
+RUNALL_CROSSLIST
+*	PM_CL="/w14365 /D_ENFORCE_FACET_SPECIALIZATIONS=1 /D_STL_CALL_ABORT_INSTEAD_OF_INVALID_PARAMETER /Zc:preprocessor"
+RUNALL_CROSSLIST
+*	PM_CL="/w14640 /Zc:threadSafeInit- /EHsc /DTEST_STANDARD=20 /std:c++20"
+*	PM_CL="/w14640 /Zc:threadSafeInit- /EHsc /DTEST_STANDARD=23 /std:c++latest"
+RUNALL_CROSSLIST
+*	PM_CL="/MD"
+*	PM_CL="/MDd"
+*	PM_CL="/MT"
+*	PM_CL="/MTd"
+*	PM_CL="/MDd /analyze:only /analyze:autolog-"
+*	PM_CL="/MDd /GR- /D_HAS_STATIC_RTTI=0"
+*	PM_CL="/MDd /utf-8"
+RUNALL_CROSSLIST
+PM_CL=""
+ASAN	PM_CL="-fsanitize=address /Zi" PM_LINK="/debug"