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a647ba250a
`#[cfg]`s are frequently used to gate crate content behind cargo features. This can lead to very confusing errors when features are missing. For example, `serde` doesn't have the `derive` feature by default. Therefore, `serde::Serialize` fails to resolve with a generic error, even though the macro is present in the docs. This commit adds a list of all stripped item names to metadata. This is filled during macro expansion and then, through a fed query, persisted in metadata. The downstream resolver can then access the metadata to look at possible candidates for mentioning in the errors. This slightly increases metadata (800k->809k for the feature-heavy windows crate), but not enough to really matter.
52 lines
1.6 KiB
Rust
52 lines
1.6 KiB
Rust
pub mod inner {
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#[cfg(FALSE)]
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pub fn uwu() {}
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//~^ NOTE found an item that was configured out
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#[cfg(FALSE)]
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pub mod doesnt_exist {
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pub fn hello() {}
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}
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pub mod wrong {
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#[cfg(feature = "suggesting me fails the test!!")]
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pub fn meow() {}
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}
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pub mod right {
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#[cfg(feature = "what-a-cool-feature")]
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pub fn meow() {}
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//~^ NOTE found an item that was configured out
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}
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}
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#[cfg(i_dont_exist_and_you_can_do_nothing_about_it)]
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pub fn vanished() {}
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fn main() {
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// There is no uwu at this path - no diagnostic.
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uwu(); //~ ERROR cannot find function
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//~^ NOTE not found in this scope
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// It does exist here - diagnostic.
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inner::uwu(); //~ ERROR cannot find function
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//~| NOTE not found in `inner`
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// The module isn't found - we would like to get a diagnostic, but currently don't due to
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// the awkward way the resolver diagnostics are currently implemented.
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// FIXME(Nilstrieb): Also add a note to the cfg diagnostic here
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inner::doesnt_exist::hello(); //~ ERROR failed to resolve
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//~| NOTE could not find `doesnt_exist` in `inner`
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// It should find the one in the right module, not the wrong one.
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inner::right::meow(); //~ ERROR cannot find function
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//~| NOTE not found in `inner::right
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//~| NOTE the item is gated behind the `what-a-cool-feature` feature
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// Exists in the crate root - we would generally want a diagnostic,
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// but currently don't have one.
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// Not that it matters much though, this is highly unlikely to confuse anyone.
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vanished(); //~ ERROR cannot find function
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//~^ NOTE not found in this scope
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}
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