Add a new `Resolve::generate_nominal_type_ids` method by alexcrichton · Pull Request #2447 · bytecodealliance/wasm-tools
This commit adds a new method to `Resolve` which is intended to resolve a longstanding issue for bindings generators based on `wit-parser`: bytecodealliance#1497. Specifically this adds functionality to `Resolve` to duplicate exported interfaces and their contents, if necessary. This is a boon to bindings generators because it means that a `TypeId`, for example, uniquely identifies a single generated type. Previously it might refer to one of two types, either the imported version or the exported version. After this method, however, there will be two `TypeId`s if necessary. This is currently modeled as a mutation to `Resolve` which is opt-in. This is done to avoid tampering with the AST-like structure of `Resolve` today where other AST-like operations don't want to necessarily have to keep everything in sync. Once a `Resolve` is nominalized, however, it's effectively incompatible with other operations such as merging, printing, etc. My thinking is that for now this is a reasonable tradeoff as bindings generators can pretty easily invoke this method before actually running bindings generation. Closes bytecodealliance#1497
alexcrichton added a commit to alexcrichton/wit-bindgen that referenced this pull request
Feb 10, 2026
This commit leverages bytecodealliance/wasm-tools#2447 to make many existing and future problems much easier in `wit-bindgen`. Namely a `TypeId` now uniquely identifies a type to be generated rather than simultaneously representing both an import and an export in some situations. This isn't immediately leveraged in bindings generators just yet but it's intended to open up the doors to benefitting from this in the future.
alexcrichton added a commit to alexcrichton/wit-bindgen that referenced this pull request
Feb 10, 2026
Previously stream/future payload were generated by collecting the set of types used in `future` and `stream` types in a WIT, rendering them to a string, deduplicating based on this string representation, and then generating various impls-with-vtables. This stringification strategy unfortunately falls down in a few situations such as: * Type aliases in WIT render as two names in Rust, but they're using the same Rust type. * Types with the same definition, but in multiple modules, will have two different paths in Rust but alias the same type. * Primitives may be used directly in streams/futures but then additionally used as a WIT type alias. In all of these situations it's effectively exposing how Rust requires at most one-impl-per-type-definition but the stringification/deduping was just a proxy for implementing this restriction and not a precise calculation. Using the work from bytecodealliance/wasm-tools#2447 as well as bytecodealliance#1468 it's possible to do all of this without stringifying. Specifically bytecodealliance#1468, transitively enabled by bytecodealliance/wasm-tools#2447, enables building a set of equal types that the Rust generator knows will all alias the same type definition. Using this it's possible to translate a payload to its "canonical payload" representation ID-wise and perform hashing/deduplication based on that. This in turn solves all of the issues above as well as previous issues such as bytecodealliance#1432 and bytecodealliance#1433 without requiring the workaround in bytecodealliance#1482. The end result is that all of these various bugs should be fixed and the Rust generator should be much more reliable about when exactly a trait impl is emitted vs not. Closes bytecodealliance#1523 Closes bytecodealliance#1524
github-merge-queue bot pushed a commit to bytecodealliance/wit-bindgen that referenced this pull request
Feb 10, 2026
* Generate nominal IDs for all bindings generation This commit leverages bytecodealliance/wasm-tools#2447 to make many existing and future problems much easier in `wit-bindgen`. Namely a `TypeId` now uniquely identifies a type to be generated rather than simultaneously representing both an import and an export in some situations. This isn't immediately leveraged in bindings generators just yet but it's intended to open up the doors to benefitting from this in the future. * Rely on nominal type ids in the rust generator No major changes just yet, but this shows some examples of removing non-obvious logic in bindings generation enabled by nominal type ids. * Fix Go CI
alexcrichton added a commit to alexcrichton/wit-bindgen that referenced this pull request
Feb 10, 2026
Previously stream/future payload were generated by collecting the set of types used in `future` and `stream` types in a WIT, rendering them to a string, deduplicating based on this string representation, and then generating various impls-with-vtables. This stringification strategy unfortunately falls down in a few situations such as: * Type aliases in WIT render as two names in Rust, but they're using the same Rust type. * Types with the same definition, but in multiple modules, will have two different paths in Rust but alias the same type. * Primitives may be used directly in streams/futures but then additionally used as a WIT type alias. In all of these situations it's effectively exposing how Rust requires at most one-impl-per-type-definition but the stringification/deduping was just a proxy for implementing this restriction and not a precise calculation. Using the work from bytecodealliance/wasm-tools#2447 as well as bytecodealliance#1468 it's possible to do all of this without stringifying. Specifically bytecodealliance#1468, transitively enabled by bytecodealliance/wasm-tools#2447, enables building a set of equal types that the Rust generator knows will all alias the same type definition. Using this it's possible to translate a payload to its "canonical payload" representation ID-wise and perform hashing/deduplication based on that. This in turn solves all of the issues above as well as previous issues such as bytecodealliance#1432 and bytecodealliance#1433 without requiring the workaround in bytecodealliance#1482. The end result is that all of these various bugs should be fixed and the Rust generator should be much more reliable about when exactly a trait impl is emitted vs not. Closes bytecodealliance#1523 Closes bytecodealliance#1524
github-merge-queue bot pushed a commit to bytecodealliance/wit-bindgen that referenced this pull request
Feb 12, 2026
* rust: Reimplement how stream/future payloads work Previously stream/future payload were generated by collecting the set of types used in `future` and `stream` types in a WIT, rendering them to a string, deduplicating based on this string representation, and then generating various impls-with-vtables. This stringification strategy unfortunately falls down in a few situations such as: * Type aliases in WIT render as two names in Rust, but they're using the same Rust type. * Types with the same definition, but in multiple modules, will have two different paths in Rust but alias the same type. * Primitives may be used directly in streams/futures but then additionally used as a WIT type alias. In all of these situations it's effectively exposing how Rust requires at most one-impl-per-type-definition but the stringification/deduping was just a proxy for implementing this restriction and not a precise calculation. Using the work from bytecodealliance/wasm-tools#2447 as well as #1468 it's possible to do all of this without stringifying. Specifically #1468, transitively enabled by bytecodealliance/wasm-tools#2447, enables building a set of equal types that the Rust generator knows will all alias the same type definition. Using this it's possible to translate a payload to its "canonical payload" representation ID-wise and perform hashing/deduplication based on that. This in turn solves all of the issues above as well as previous issues such as #1432 and #1433 without requiring the workaround in #1482. The end result is that all of these various bugs should be fixed and the Rust generator should be much more reliable about when exactly a trait impl is emitted vs not. Closes #1523 Closes #1524 * Try fixing CI * Fix typo * Fix rust CI
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