Пост🫧 Tolk v1.2: rich bounced messages, cheap deployment, and a breaking change that you'll love

🫧 Tolk v1.2: rich bounced messages, cheap deployment, and a breaking change that you'll love Tolk v1.2 is here, aligned with TVM 12 — bringing new assembler instructions that make contracts cheaper and cleaner. This update introduces one breaking change, several powerful new capabilities, and a few quality-of-life improvements across the compiler. ✅ Notable changes in Tolk v1.2: 1. Breaking change: address is now "internal only" 2. Rich bounces: not 256 bits, but the full body on bounce 3. Cheap builder-to-slice, StateInit, and address composition 4. Improved compilation errors 5. Anonymous functions (lambdas) 6. Borrow checker to catch undefined behavior PR on GitHub with detailed info. ✔ `address` is now "internal only" Before: * address meant internal/external/none Now: * address — internal only * address? (nullable) — internal/none, exactly like "maybe address" in @ton/core * any_address — internal/external/none In 99% of contracts only internal addresses are used. External ones are rare, and "none" can be expressed as nullable. struct Storage { // internal, checked automatically owner: address } With new TVM 12 instructions, addresses are validated automatically during (de)serialization without extra gas — no more manual isInternal() checks. So yes, it's technically a breaking change, but it removes a ton of noise. A short migration guide, as well as technical details, available here. ✔ Rich bounced messages Historically, a bounced message only returned the first 256 bits of the original body. Now TVM 12 supports rich bounces — which lets you obtain the entire body instead. createMessage({     bounce: BounceMode.RichBounce,     ... }) In onBouncedMessage, you get access to the original body, exit code, gas used, and more. Old true/false bounce flags still work for backward compatibility. Rich bounces simplify complex message flows and inter-contract communication — one of the most painful aspects of TON until now. ✔ Cheap builder-to-slice and address composition Previously, converting a builder to a slice (endCell + beginParse) consumed a lot of gas because cells are expensive. Now there's a new instruction — BTOS (builder-to-slice) — without intermediate cell creation. - b.endCell().beginParse() is now cheap: auto-optimized to BTOS - "builder-to-address" is the same BTOS; hacks around "return a builder with a valid address" can be removed - cheaper StateInit hashing and address calculations Just update to Tolk v1.2 + TVM 12, and you'll immediately save gas. ✔ Anonymous functions (lambdas) Can be used in general-purpose frameworks, perfectly integrated with the type system: fun customRead(reader: (slice) -> int) { ... } customRead(fun(s) { return s.loadUint(32) }) ✔ Low-level compiler enhancements Also included: better diagnostics with precise ranges, new peephole optimizations, tuple ↔ object conversions, and multiple small fixes. A lightweight borrow checker prevents undefined behavior on concurrent mutations. As always, all additions are carefully described in a PR. 🌳 We've also started improving TVM itself — new assembler instructions are designed specifically to fit the Tolk type system and optimizer. I have always said: the language is just the beginning. Perfect developer experience requires improving every layer of TON's stack. The road may be sharp and curvy — but we're definitely heading in the right direction.