clang-21 on macos fixes

[AaronRobinsonMSFT]

Addresses various build failures when compiling with the latest Xcode.

% clang --version
Apple clang version 21.0.0 (clang-2100.0.123.102)
Target: arm64-apple-darwin25.4.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

See #119706 (comment)

Clang 21 changes for -Wc++-keyword - https://releases.llvm.org/21.1.0/tools/clang/docs/ReleaseNotes.html#id11
Partially related unicode-org/icu#2913

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[Copilot]

Pull request overview

Addresses build failures / new diagnostics when compiling dotnet/runtime native components with newer Clang/Xcode toolchains (e.g., Apple clang 21), primarily by tightening up pointer/CF type conversions and suppressing a new ICU-header warning.

Changes:

• Add explicit casts to satisfy newer Clang diagnostics around implicit void* conversions and CoreFoundation type APIs.
• Minor Objective-C formatting cleanups in Network.framework PAL.
• Suppress -Wc++-keyword warnings when building System.Globalization.Native (ICU headers).

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/native/libs/System.Security.Cryptography.Native.Apple/pal_x509chain.c	Add explicit malloc cast to avoid new implicit void* conversion diagnostics.
src/native/libs/System.Security.Cryptography.Native.Apple/pal_ssl.c	Add casts for CF APIs (bytes pointer + CFArray element type).
src/native/libs/System.Security.Cryptography.Native.Apple/pal_networkframework.m	Formatting cleanups and cast to tls_ciphersuite_t for Clang strictness.
src/native/libs/System.Security.Cryptography.Native.Apple/pal_ecc.c	Cast CFDictionaryGetValue result to CFNumberRef for stricter compilation.
src/native/libs/System.Native/pal_networking.c	Add casts on calloc return to satisfy stricter pointer conversion rules (Darwin unlimited select path).
src/native/libs/System.Native/pal_environment.m	Add explicit malloc cast to avoid new implicit void* conversion diagnostics.
src/native/libs/System.Globalization.Native/CMakeLists.txt	Suppress Clang warning -Wc++-keyword likely triggered by ICU headers.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

[AaronRobinsonMSFT]

FYI @am11

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

[am11]

This gets us through the native build with Apple clang 21. There are two (non-fatal) warnings:

When building src/tests native components:

[372/376] Generating SwiftErrorHandling library
/Users/adeel/projects/runtime2/src/tests/Interop/Swift/SwiftErrorHandling/SwiftErrorHandling.swift:7:10: warning: associated value 'runtimeError(message:)' of 'Sendable'-conforming enum 'MyError' contains non-Sendable type 'NSString'
 5 | 
 6 | public enum MyError: Error {
 7 |     case runtimeError(message: NSString)
   |          `- warning: associated value 'runtimeError(message:)' of 'Sendable'-conforming enum 'MyError' contains non-Sendable type 'NSString'
 8 | }
 9 | 

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.4.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSString.h:103:12: note: class 'NSString' does not conform to the 'Sendable' protocol
101 | 
102 | 
103 | @interface NSString : NSObject <NSCopying, NSMutableCopying, NSSecureCoding>
    |            `- note: class 'NSString' does not conform to the 'Sendable' protocol
104 | 
105 | #pragma mark *** String funnel methods ***
[375/376] Install the project...
-- Install configuration: "DEBUG"

When building libs.native:

[141/288] Building C object System.Native/CMakeFiles/System.Native.dir/pal_memory.c.o
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:22:7: warning: function SystemNative_AlignedAlloc might be an allocator wrapper [-Wallocator-wrappers]
   22 | void* SystemNative_AlignedAlloc(uintptr_t alignment, uintptr_t size)
      |       ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:26:5: note: value obtained from allocator call is returned here
   26 |     return aligned_alloc(alignment, size);
      |     ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:70:7: warning: function SystemNative_Calloc might be an allocator wrapper [-Wallocator-wrappers]
   70 | void* SystemNative_Calloc(uintptr_t num, uintptr_t size)
      |       ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:72:5: note: value obtained from allocator call is returned here
   72 |     return calloc(num, size);
      |     ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:80:7: warning: function SystemNative_Malloc might be an allocator wrapper [-Wallocator-wrappers]
   80 | void* SystemNative_Malloc(uintptr_t size)
      |       ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:82:5: note: value obtained from allocator call is returned here
   82 |     return malloc(size);
      |     ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:85:7: warning: function SystemNative_Realloc might be an allocator wrapper [-Wallocator-wrappers]
   85 | void* SystemNative_Realloc(void* ptr, uintptr_t new_size)
      |       ^
/Users/adeel/projects/runtime2/src/native/libs/System.Native/pal_memory.c:87:5: note: value obtained from allocator call is returned here
   87 |     return realloc(ptr, new_size);
      |     ^
4 warnings generated.

We can figure out best way to fix them in a follow-up.

[AaronRobinsonMSFT]

This gets us through the native build with Apple clang 21. There are two (non-fatal) warnings:

Forgot about the -Wallocator-wrappers ones. Thanks for calling out the test failures, updated.

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/tests/Interop/Swift/SwiftErrorHandling/SwiftErrorHandling.swift:35

• getMyErrorMessage returns nil when the error is not MyError, but it never sets messageLength in that path. The C# P/Invoke uses an out int length, so this can surface as an uninitialized length value if the cast fails. Set messageLength = 0 before returning nil (or initialize it at function entry).

public func getMyErrorMessage(from error: Error, messageLength: inout Int32) -> UnsafePointer<unichar>? {
    if let myError = error as? MyError {
        switch myError {
        case .runtimeError(let message):
            let nsMessage = message as NSString
            let buffer = UnsafeMutableBufferPointer<unichar>.allocate(capacity: nsMessage.length)
            nsMessage.getCharacters(buffer.baseAddress!, range: NSRange(location: 0, length: nsMessage.length))
            messageLength = Int32(nsMessage.length)
            return UnsafePointer(buffer.baseAddress!)
        }
    }
    return nil