Create anon const defs in DefCollector unconditionally#133285
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BoxyUwU wants to merge 1 commit intorust-lang:masterfrom
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Create anon const defs in DefCollector unconditionally#133285BoxyUwU wants to merge 1 commit intorust-lang:masterfrom
DefCollector unconditionally#133285BoxyUwU wants to merge 1 commit intorust-lang:masterfrom
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Should also add the following test: struct Foo<const N: usize>;
macro_rules! expands_to_n {
() => {
N
};
}
macro_rules! empty {
() => {};
}
const N: usize = 10;
type A = Foo<
{
empty! {}
expands_to_n! {}
},
>;which demonstrates why we cant simply special case a fully expanded const argument being |
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Actually going to close this until lcnr has had a chance to play around with this since they said they wanted to take a look and see if they could find a clean way to make this work |
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Nov 28, 2024
always create `DefId`s for anon consts but don't use them anywhere, we intentionally don't encode them in the crate metadata. best reviewed by disabling whitespace. This pretty much reimplements rust-lang#133285 while adding the tests of rust-lang#133455. Fixes rust-lang#133064 r? `@BoxyUwU` `@compiler-errors`
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Fixes #133064
Macros in statement position can expand to nothing which fundamentally breaks any attempt to not create
DefIds that don't need to be created. When a macro expands to nothing we never callvisit_expron its expanded results so never create theDefIdfor the anon const which leads to ICEs. So... just completely give up on this and make def encoding deal with having defids exist that shouldn't.Alternatively we could make
macro!{}never expand to nothing and always atleast be an empty statement, this would be a breaking change due to:compiling on stable
r? @compiler-errors