Closed
Description
openedon Apr 6, 2023
Code
pub fn foo(x: &str) -> Result<(), Box<dyn std::error::Error>> {
Err(format!("error: {x}"))
}Current output
Checking foo v0.1.0 (/Users/eric/Temp/foo)
error[E0308]: mismatched types
--> src/lib.rs:2:9
|
2 | Err(format!("error: {x}"))
| ^^^^^^^^^^^^^^^^^^^^^ expected `Box<dyn Error>`, found `String`
|
= note: expected struct `Box<dyn std::error::Error>`
found struct `String`
= note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
--> /Users/eric/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/alloc/src/macros.rs:121:12
|
12| res.into()
| +++++++
For more information about this error, try `rustc --explain E0308`.
error: could not compile `foo` (lib) due to previous errorDesired output
Checking foo v0.1.0 (/Users/eric/Temp/foo)
error[E0308]: mismatched types
--> src/lib.rs:2:9
|
2 | Err(format!("error: {x}"))
| ^^^^^^^^^^^^^^^^^^^^^ expected `Box<dyn Error>`, found `String`
|
= note: expected struct `Box<dyn std::error::Error>`
found struct `String`
= note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
--> /Users/eric/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/alloc/src/macros.rs:121:12
|
12| Err(format!("error: {x}").into())
| +++++++
For more information about this error, try `rustc --explain E0308`.
error: could not compile `foo` (lib) due to previous errorRationale and extra context
The suggestion converts the code to:
Err(.into())
which is invalid.
It should suggest:
Err(format!("error: {x}").into())
The suggestion works correctly for non-macro string values.
This suggestion was introduced in #102496.
Other cases
No response
Anything else?
rustc 1.70.0-nightly (cf7ada217 2023-04-03)
binary: rustc
commit-hash: cf7ada217c8ac63367b184afd9fffaff30f6ed44
commit-date: 2023-04-03
host: aarch64-apple-darwin
release: 1.70.0-nightly
LLVM version: 16.0.0
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