Disallow non-type/instance aliases in component/instance types#2462
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alexcrichton merged 1 commit intobytecodealliance:mainfrom Mar 31, 2026
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This fixes a bug in the validation of components where previously invalid `alias` items were allowed to be present in `instance` and `component` type definitions. The specification indicates that these should be disallowed and `wasmparser` erroneously allowed them. The impact of this change is expected to be nonexistent or negligible as this only applies to handwritten components. Components produced by `wit-component` do not use this feature so no previously produced component should be rejected. Additionally the impact of allowing these invalid `alias` annotations is also negligible as you couldn't actually do anything with the item anyway so it was just sort of dead bloat in a binary. cc WebAssembly/component-model#621
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cc @lukewagner mind double-checking the logic here too? |
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ping @dicej mind taking a look at this? |
dicej
approved these changes
Mar 31, 2026
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This fixes a bug in the validation of components where previously invalid
aliasitems were allowed to be present ininstanceandcomponenttype definitions. The specification indicates that these should be disallowed andwasmparsererroneously allowed them. The impact of this change is expected to be nonexistent or negligible as this only applies to handwritten components. Components produced bywit-componentdo not use this feature so no previously produced component should be rejected. Additionally the impact of allowing these invalidaliasannotations is also negligible as you couldn't actually do anything with the item anyway so it was just sort of dead bloat in a binary.cc WebAssembly/component-model#621