If you’ve ever written async Rust, you know the pain. You’re cruising along, building a futures-based pipeline, and then you hit it — Pin. Suddenly you’re reading documentation about “structural” and “non-structural” Pin implementations, self-referential structs, and whether your type is Unpin. You didn’t sign up for a PhD in type theory. You just wanted to read a file asynchronously.
Pin is the tax Rust made you pay for a problem the language should have solved itself.
For nearly a decade, the Rust community has lived with this hack. Pin<T> was introduced to work around a fundamental gap: Rust types are movable by default, but self-referential structures — the kind that async/await generates behind the scenes — can’t be safely moved in memory. Instead of fixing the type system, the language bolted on a wrapper that shifts the burden onto every developer who touches async code.
That’s changing. The Rust project has set a 2026 goal to natively support immobile types and guaranteed destructors. Translation: the language is finally growing the feature it should have had since day one.
Here’s why this matters more than you think.
Most developers hear “immobile types” and think “nice, cleaner async.” That’s like hearing “the printing press” and thinking “nice, faster book copying.” The async ergonomics improvement is real and welcome — no more Pin boilerplate, no more pin_project! macros, no more three-hour debugging sessions where you realize your Future isn’t Unpin. But the bigger story is hiding in plain sight in the project goal document itself.
Immobile types are the doorway to linear types, and linear types change everything about how Rust handles resources.
Right now, Rust has a dirty secret: you can leak any value safely. mem::forget is safe. Reference cycles can leak values. The compiler won’t stop you. This means Rust’s destructor guarantees are… not actually guarantees. They’re suggestions with good intentions. Your file descriptor might never close. Your GPU memory might never free. Your network socket might hang open forever. The language calls this “safe” because it can’t prove otherwise.
Linear types fix this. A linear type is a value that must be consumed — you can’t drop it without calling a specific function that takes it by value. You can’t forget it. You can’t leak it. The compiler enforces it at every call site.
Think about what that means for resource management. File handles that are impossible to leak. GPU buffers that are guaranteed to free. Database connections that will close. Not because developers remember to do it — because the type system makes it impossible not to.
The difference between a safe language and a correct language is whether the compiler can prove your resources are handled. Rust is about to cross that line.
Now, the skeptics in the comments are already typing: “What about reference cycles? You can leak through Rc cycles and the compiler can’t detect that.” You’re right — and that’s why this is a language-level goal, not a library tweak. The proposal acknowledges this. The path to guaranteed destructors requires rethinking how the language handles ownership at a fundamental level, including how reference cycles interact with linear types. It’s ambitious. It might not land perfectly in 2026. But the direction is clear.
What makes this genuinely exciting isn’t just the technical elegance. It’s that the Rust team found a way to do it without breaking existing code. For years, the consensus was that immobile types couldn’t be added to Rust without a breaking change — that Pin was the price of backward compatibility. That consensus was wrong. The project goal document outlines an approach that introduces immobile types as an opt-in, additive feature. Old code keeps working. New code gets the better primitives.
The best language evolution doesn’t rewrite history — it makes the hacks obsolete by giving you no reason to reach for them.
If you write Rust, especially async Rust, this is the most important change to the language since async/await itself. It removes the single most common source of confusion for new Rust developers. It eliminates an entire category of bugs related to resource leaks. And it opens patterns that today require unsafe code or runtime checks — patterns that GPU programming, embedded systems, and high-performance networking have been begging for.
The Pin hack had a good run. It kept async Rust usable for years when the alternative was a breaking change nobody wanted. But hacks have a shelf life, and this one expired the moment the language committed to solving the underlying problem.
Every hack is a debt. The best languages pay it off before interest compounds. Rust just made the payment.
FAQ
Q: Won't reference cycles still let you leak values, making guaranteed destructors impossible?
A: Yes, Rc cycles can leak values today. The proposal acknowledges this — guaranteed destructors require the language to handle how reference cycles interact with linear types. It's not solved yet, but the 2026 goal is the first serious step toward solving it at the type-system level rather than pretending mem::forget being safe is fine.
Q: What does this actually change for my daily Rust code?
A: If you write async, you stop fighting Pin. No more pin_project macros, no more Unpin confusion. If you manage resources like file handles or GPU memory, you get types that the compiler guarantees will be properly disposed of — no leaks, no forgotten cleanup, no runtime checks needed.
Q: Is this just adding complexity to fix complexity?
A: No — it's removing complexity. Pin was the complexity. It existed because the language lacked immobile types. Adding immobile types natively means Pin becomes a relic. The net result is simpler code, not more complex code. The macro disappears; the compiler does the work.