Compiler Markers

These marker attributes tell the compiler how it may treat a declaration. Most application code does not need them.

Inline control

• #[AlwaysInline] asks the optimizer to inline a resolved function or method.
• #[NeverInline] forbids inlining.
• #[Cold] marks a rare function or method and keeps it out of line.

These markers do not change a program’s result. They may change its bytecode, speed, code size, and stack trace. Measure before adding them.

Frameless

#[Frameless] marks an eligible function or method that can run without a call frame. The callable must take no parameters and return a literal value. The compiler rejects other shapes.

Frameless calls cannot hold normal call state. Use the marker only for tiny constant accessors supplied by the standard library.

Inheritance checks

#[ConsistentConstructor] makes child constructors keep a signature that is compatible with the parent constructor.

#[ConsistentGenerics] makes inherited generic bounds stay equal through the class family.

Both markers belong on classes. They let code use a class family without finding a different construction or generic contract on one child.

Stub

#[Stub] gives source tools the signature of a symbol whose implementation already exists in the language core. The compiler checks that the real symbol exists and matches the stub, then skips the source body.

The optional reason says why the symbol is a stub. The optional issue records the tracked speed work for a temporary built-in implementation.

namespace Whim\_Private;

use Whim\Marker\Stub;

#[Stub]
function getmypid(): (1..) {}

Only the standard library should declare stubs. A normal package must provide the code it declares.