Point out the known type when field doesn't satisfy bound #38150
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(rust_highfive has picked a reviewer for you, use r? to override) |
| let (post_message, pre_message) = | ||
| if let ObligationCauseCode::BuiltinDerivedObligation(ref data) | ||
| = obligation.cause.code | ||
| { |
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This brace should be on the previous line.
For file
```rust
use std::path::Path;
fn f(p: Path) { }
```
provide the following error
```nocode
error[E0277]: the trait bound `[u8]: std::marker::Sized` is not satisfied in `std::path::Path`
--> file.rs:3:6
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3 | fn f(p: Path) { }
| ^ within `std::path::Path`, the trait `std::marker::Sized` is not implemented for `[u8]`
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= note: `[u8]` does not have a constant size known at compile-time
= note: required because it appears within the type `std::path::Path`
= note: all local variables must have a statically known size
```
| let (post_message, pre_message) = | ||
| if let ObligationCauseCode::BuiltinDerivedObligation(ref data) | ||
| = obligation.cause.code { | ||
| let parent_trait_ref = self.resolve_type_vars_if_possible( |
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Missing an indent level here.
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Is it? the if let is part of the previous line, the only reason is below is because I couldn't get to fit nicely in under 100 chars. In this were to fit in one line it would be:
let (post_message, pre_message) = if let ObligationCauseCode::BuiltinDerivedObligation(ref data) = obligation.cause.code {I don't see why then line 493 would have to have double indentation. :)
I agree that it is slightly confusing as it is now, but haven't come up with a better way of presenting this.
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Oh indeed, you're absolutely right, my bad!
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one better way might be using match :)
let (post_message, pre_message) = match obligation.cause.code {
ObligationCauseCode::BuiltinDerivedObligation(ref data) => {
let parent_trait_ref = self.resolve_type_vars_if_possible(
...
}
_ => {
(String::new(), String::new())
}
};
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All good for me. I'm not sure I'm supposed to merge this so I'll wait for others' opinion. |
| let (post_message, pre_message) = | ||
| if let ObligationCauseCode::BuiltinDerivedObligation(ref data) | ||
| = obligation.cause.code { | ||
| let parent_trait_ref = self.resolve_type_vars_if_possible( |
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one better way might be using match :)
let (post_message, pre_message) = match obligation.cause.code {
ObligationCauseCode::BuiltinDerivedObligation(ref data) => {
let parent_trait_ref = self.resolve_type_vars_if_possible(
...
}
_ => {
(String::new(), String::new())
}
};| = obligation.cause.code { | ||
| let parent_trait_ref = self.resolve_type_vars_if_possible( | ||
| &data.parent_trait_ref); | ||
| (format!(" in `{}`", parent_trait_ref.0.self_ty()), |
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One concern I have is that this only goes up one level, but there are similar cases where multiple levels are needed. For example, it'd be nice if this patch addressed this example: https://is.gd/BZjfP6
The current output is
error[E0277]: the trait bound `*const u8: std::marker::Send` is not satisfied
--> <anon>:16:5
|
16 | is_send::<Foo>();
| ^^^^^^^^^^^^^^ trait `*const u8: std::marker::Send` not satisfied
|
= note: `*const u8` cannot be sent between threads safely
= note: required because it appears within the type `Baz`
= note: required because it appears within the type `Bar`
= note: required because it appears within the type `Foo`
= note: required by `is_send`
and I think your suggested approach would be a big improvement:
error[E0277]: within `Foo`, the trait bound `*const u8: std::marker::Send` is not satisfied
--> <anon>:16:5
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16 | is_send::<Foo>();
| ^^^^^^^^^^^^^^ trait `*const u8: std::marker::Send` not satisfied
|
= note: `*const u8` cannot be sent between threads safely
= note: required because it appears within the type `Baz`
= note: required because it appears within the type `Bar`
= note: required because it appears within the type `Foo`
= note: required by `is_send`
But I believe your patch as is will print "within Baz" instead.
should be easy enough though -- just have to iterate on the cause chain rather than just going up one level.
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Added test for new case and a recursive search up the cause chain.
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@bors r+ |
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📌 Commit 5c13041 has been approved by |
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⌛ Testing commit 5c13041 with merge 27122ab... |
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💔 Test failed - auto-win-gnu-64-opt |
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@bors: retry
…On Mon, Dec 19, 2016 at 6:11 PM, bors ***@***.***> wrote:
💔 Test failed - auto-win-gnu-64-opt
<https://buildbot.rust-lang.org/builders/auto-win-gnu-64-opt/builds/6460>
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<#38150 (comment)>, or mute
the thread
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Point out the known type when field doesn't satisfy bound
For file
```rust
use std::path::Path;
fn f(p: Path) { }
```
provide the following error
```nocode
error[E0277]: the trait bound `[u8]: std::marker::Sized` is not satisfied in `std::path::Path`
--> file.rs:3:6
|
3 | fn f(p: Path) { }
| ^ within `std::path::Path`, the trait `std::marker::Sized` is not implemented for `[u8]`
|
= note: `[u8]` does not have a constant size known at compile-time
= note: required because it appears within the type `std::path::Path`
= note: all local variables must have a statically known size
```
Fix rust-lang#23286.
Rollup of 29 pull requests - Successful merges: #37761, #38006, #38131, #38150, #38158, #38171, #38208, #38215, #38236, #38245, #38289, #38302, #38315, #38346, #38388, #38395, #38398, #38418, #38432, #38451, #38463, #38468, #38470, #38471, #38472, #38478, #38486, #38493, #38498 - Failed merges: #38271, #38483
For file
provide the following error
Fix #23286.