Rollup merge of #59268 - estebank:from-string, r=QuietMisdreavus
Add suggestion to use `&*var` when `&str: From<String>` is expected Fix #53879.
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e5fa59735b
@ -138,3 +138,16 @@ error[E0277]: `&str` is not an iterator
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= help: the trait `std::iter::Iterator` is not implemented for `&str`
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= note: required by `std::iter::IntoIterator::into_iter`
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```
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If you need to filter on multiple attributes, you can use `all`, `any` or
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`not` in the following way:
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```rust,compile_fail
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#[rustc_on_unimplemented(
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on(
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all(_Self="&str", T="std::string::String"),
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note="you can coerce a `{T}` into a `{Self}` by writing `&*variable`"
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)
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)]
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pub trait From<T>: Sized { /* ... */ }
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```
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@ -363,6 +363,12 @@ pub trait Into<T>: Sized {
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/// [`from`]: trait.From.html#tymethod.from
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/// [book]: ../../book/ch09-00-error-handling.html
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#[stable(feature = "rust1", since = "1.0.0")]
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#[rustc_on_unimplemented(
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on(
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all(_Self="&str", T="std::string::String"),
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note="to coerce a `{T}` into a `{Self}`, use `&*` as a prefix",
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)
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)]
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pub trait From<T>: Sized {
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/// Performs the conversion.
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#[stable(feature = "rust1", since = "1.0.0")]
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6
src/test/ui/suggestions/into-str.rs
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6
src/test/ui/suggestions/into-str.rs
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@ -0,0 +1,6 @@
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fn foo<'a, T>(_t: T) where T: Into<&'a str> {}
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fn main() {
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foo(String::new());
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//~^ ERROR the trait bound `&str: std::convert::From<std::string::String>` is not satisfied
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}
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17
src/test/ui/suggestions/into-str.stderr
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17
src/test/ui/suggestions/into-str.stderr
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@ -0,0 +1,17 @@
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error[E0277]: the trait bound `&str: std::convert::From<std::string::String>` is not satisfied
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--> $DIR/into-str.rs:4:5
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LL | foo(String::new());
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| ^^^ the trait `std::convert::From<std::string::String>` is not implemented for `&str`
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= note: to coerce a `std::string::String` into a `&str`, use `&*` as a prefix
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= note: required because of the requirements on the impl of `std::convert::Into<&str>` for `std::string::String`
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note: required by `foo`
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--> $DIR/into-str.rs:1:1
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LL | fn foo<'a, T>(_t: T) where T: Into<&'a str> {}
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0277`.
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