compiler-warnings

name	compiler-warnings
description	Compiler warning policy and suppression patterns for MSVC /Wall. Use when fixing warnings, adding pragma suppressions, or dealing with C4365, C5219, C4625, C4626 and other compiler diagnostics.
metadata	{"author":"RedSalamander","version":"1.0"}

Compiler Warnings Policy

Objective: zero actionable warnings under /Wall.

Critical Rule

Production/runtime projects should fix warnings at the root cause or suppress locally with #pragma warning(push/disable/pop) and a rationale.

New project-wide suppressions require:

• rationale,
• owner,
• expiry/review task,
• narrowest possible scope.

Test projects may carry broader project-local suppressions only when they intentionally aggregate SDK/WIL/STL/product-source-heavy translation units, and the project file documents the exception.

Acceptable Global Suppressions

• /wd5045 - Spectre mitigation
• /wd4820 - Padding
• /wd4710 - Not inlined
• /wd4711 - Auto inline
• /wd4514 - Unreferenced inline

Required Fixes (Project Code)

Warning	Fix
C4365	static_cast<T>() for signed/unsigned
C5219	Explicit cast for data loss
C5264	Remove unused or add [[maybe_unused]]
C4464	Fix include paths, avoid ..
C4774	Do not use runtime printf-format strings; use FormatStringResource(...) (resources) or std::format

C4774: Format String Not String Literal

Do not suppress C4774 to keep using swprintf_s with a runtime format string (especially from resources).

Preferred fixes:

• Localized/user-facing: change the .rc string to std::format-style positional placeholders ({0}, {1:08X}, ...), keep source placeholder order aligned with the FormatStringResource(...) argument order, and use FormatStringResource(...).
• Diagnostics: use std::format / std::format_to_n instead of *printf_s.

Pragma Patterns

WIL/System Headers

#pragma warning(push)
#pragma warning(disable: 4625 4626 5026 5027 4514 28182) // Deleted operators
#include <wil/resource.h>
#pragma warning(pop)

Windows SDK

#pragma warning(push)
#pragma warning(disable: 4820) // Padding
#include <windows.h>
#pragma warning(pop)

Fix Patterns

// Signed/unsigned conversion
size_t count = items.size();
int intCount = static_cast<int>(count);

// Unsigned literals
for (size_t i = 0u; i < count; ++i) { }

// Unused variable
[[maybe_unused]] const int kDebugFlag = 1;

Always Comment Suppressions

#pragma warning(disable: 4625) // Copy constructor deleted

For project-file suppressions, include XML comments for owner, rationale, expiry/review, and scope. C5039 callback exception-spec warnings are production-sensitive: fix or locally justify them at the callback boundary instead of hiding them at project scope.

Additional Fix Patterns

// Double-casting for complex type chains
auto val = static_cast<float>(static_cast<int>(source));

// Template safety with static_assert
template<typename T>
void Process(T value) {
    static_assert(std::is_integral_v<T>, "T must be integral");
}

Build Configuration

• Support Debug and Release configurations
• Enable /Wall (EnableAllWarnings) for first-party projects
• Use static analysis tools (PVS-Studio, Clang-Tidy)
• Configure proper optimization flags for Release

Testing and Quality

• Use static analysis tools regularly
• Follow consistent formatting (.clang-format)
• Write unit tests for complex logic
• Perform regular code reviews
• Profile graphics-intensive operations
• Test with large datasets
• Validate memory usage patterns
• Test on different DPI settings