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ebfac4ecaf
Using an error type instead of `()` avoids the duplicated errors
on `struct SUnsizedField` in `deriving-from-wrong-target.rs`. It also
improves the expanded output from this:
```
struct S2(u32, u32);
impl ::core::convert::From<()> for S2 {
#[inline]
fn from(value: ()) -> S2 { (/*ERROR*/) }
}
```
to this:
```
struct S2(u32, u32);
impl ::core::convert::From<(/*ERROR*/)> for S2 {
#[inline]
fn from(value: (/*ERROR*/)) -> S2 { (/*ERROR*/) }
}
```
The new code also only matchs on `item.kind` once.
38 lines
737 B
Rust
38 lines
737 B
Rust
//@ check-fail
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#![feature(derive_from)]
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#![allow(dead_code)]
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use std::from::From;
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#[derive(From)]
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//~^ ERROR `#[derive(From)]` used on a struct with no fields
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struct S1;
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#[derive(From)]
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//~^ ERROR `#[derive(From)]` used on a struct with no fields
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struct S2 {}
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#[derive(From)]
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//~^ ERROR `#[derive(From)]` used on a struct with multiple fields
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struct S3(u32, bool);
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#[derive(From)]
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//~^ ERROR `#[derive(From)]` used on a struct with multiple fields
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struct S4 {
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a: u32,
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b: bool,
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}
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#[derive(From)]
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//~^ ERROR `#[derive(From)]` used on an enum
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enum E1 {}
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#[derive(From)]
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struct SUnsizedField<T: ?Sized> {
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last: T,
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//~^ ERROR the size for values of type `T` cannot be known at compilation time [E0277]
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}
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fn main() {}
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