Improve error output for "expected value, found type parameter" #124634
Description
Code
pub fn delayed_insert<'a, T, C: Clone + Component>
(ecommands: &'a mut EntityCommands<'a>,
delay: Duration, c: C)
-> &'a mut EntityCommands<'a> {
ecommands.insert(DelayedInsert<T, C>::new(delay, c))
}Current output
error[E0423]: expected value, found type parameter `T`
--> src/delay.rs:22:36
|
18 | pub fn delayed_insert<'a, T, C: Clone + Component>
| - found this type parameter
...
22 | ecommands.insert(DelayedInsert<T, C>::new(delay, c))
| ^ help: a local variable with a similar name exists: `c`Desired output
error[E0423]: expected value, found type parameter `T`
--> src/delay.rs:22:36
|
18 | pub fn delayed_insert<'a, T, C: Clone + Component>
| - found this type parameter
...
22 | ecommands.insert(DelayedInsert<T, C>::new(delay, c))
| ^ help: a local variable with a similar name exists: `c`
| ^ alternate help: Substituting ::< for < may fix thisRationale and extra context
In some cases rustc correctly suggests that the turbofish syntax is required.
Here, however, it looks like user intent is ambiguous and the compiler expects a comparison operator (which expects a value on the right of the < operator) but the error help doesn't offer the "correct" suggestion. So it may be helpful to offer an aldditional suggestion whenever the output is "expected value, found type parameter": use turbofish syntax.
I suspect this shouldn't require gathering or printing any more information than the compiler already has at-hand in this context -- a static, alternative, suggestion is likely all that'd be needed.
Other cases
No response
Rust Version
rustc 1.77.2 (25ef9e3d8 2024-04-09)
binary: rustc
commit-hash: 25ef9e3d85d934b27d9dada2f9dd52b1dc63bb04
commit-date: 2024-04-09
host: x86_64-unknown-linux-gnu
release: 1.77.2
LLVM version: 17.0.6Anything else?
Might be as easy to close this issue as looking for that string in the rustc source and modifying an existing output string.
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