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wac expects "instantiation" of type aliaes #152
Description
Hi, I noticed wac compose will fail if the world of the component I'm instantiating includes a type alias like so
world my-component {
type my-alias = u32;
export foo: func(x: my-alias) -> my-alias;
}If I instantiate this in wac
let my-component = new wacdebug:my-component {};
it will fail
× missing instantiation argument `my-alias` for package `wacdebug:my-component`
╭─[default.wac:3:24]
2 │
3 │ let my-component = new wacdebug:my-component {};
· ──────────┬──────────
· ╰── missing argument `my-alias`
╰────
Instantiating a type alias makes no sense to me, it is not an import. Did I miss anything?
Activity
fibonacci1729 commentedon Feb 6, 2025
This is just a nuance of wit<->component translation/encoding where top-level types (e.g.
my-alias) are implicitly considered imports.For a component targeting your world, if you
wasm-tools print wacdebug.wasm --skeletonyou'll see:To fix this you can tell wac to import any arguments you are not directly providing, i.e.:
leon-thomm commentedon Feb 6, 2025
Ah that works! Maybe wac could have a more telling error here.
why is that? How should I think about imports on the component (encoding) level?