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Explicit help message for binop type missmatch

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When trying to do a binary operation with missing implementation, for
example `1 + Some(2)`, provide an explicit help message:

```
note: no implementation for `{integer} + std::option::Option<{integer}>`
```

Use `rustc_on_unimplemented` for the suggestions. Move cfail test to ui.
This commit is contained in:
Esteban Küber 2017-04-10 14:17:49 -07:00
parent d616f47cd0
commit be8787dfe5
8 changed files with 164 additions and 17 deletions
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2
src/libcore/cmp.rs
View File

@ -102,6 +102,7 @@
/// ```
#[lang = "eq"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "can't compare `{Self}` with `{Rhs}`"]
pub trait PartialEq<Rhs: ?Sized = Self> {
/// This method tests for `self` and `other` values to be equal, and is used
/// by `==`.
@ -550,6 +551,7 @@ fn partial_cmp(&self, other: &Ordering) -> Option<Ordering> {
/// ```
#[lang = "ord"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "can't compare `{Self}` with `{Rhs}`"]
pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
/// This method returns an ordering between `self` and `other` values if one exists.
///

20
src/libcore/ops.rs
View File

@ -242,6 +242,7 @@ pub trait Drop {
/// [std::time::SystemTime]: ../../std/time/struct.SystemTime.html
#[lang = "add"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} + {RHS}`"]
pub trait Add<RHS=Self> {
/// The resulting type after applying the `+` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -315,6 +316,7 @@ fn add(self, other: $t) -> $t { self + other }
/// [std::time::SystemTime]: ../../std/time/struct.SystemTime.html
#[lang = "sub"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} - {RHS}`"]
pub trait Sub<RHS=Self> {
/// The resulting type after applying the `-` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -437,6 +439,7 @@ fn sub(self, other: $t) -> $t { self - other }
/// ```
#[lang = "mul"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} * {RHS}`"]
pub trait Mul<RHS=Self> {
/// The resulting type after applying the `*` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -565,6 +568,7 @@ fn mul(self, other: $t) -> $t { self * other }
/// ```
#[lang = "div"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} / {RHS}`"]
pub trait Div<RHS=Self> {
/// The resulting type after applying the `/` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -644,6 +648,7 @@ fn div(self, other: $t) -> $t { self / other }
/// ```
#[lang = "rem"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} % {RHS}`"]
pub trait Rem<RHS=Self> {
/// The resulting type after applying the `%` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -883,6 +888,7 @@ fn not(self) -> $t { !self }
/// ```
#[lang = "bitand"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} & {RHS}`"]
pub trait BitAnd<RHS=Self> {
/// The resulting type after applying the `&` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -966,6 +972,7 @@ fn bitand(self, rhs: $t) -> $t { self & rhs }
/// ```
#[lang = "bitor"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} | {RHS}`"]
pub trait BitOr<RHS=Self> {
/// The resulting type after applying the `|` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -1052,6 +1059,7 @@ fn bitor(self, rhs: $t) -> $t { self | rhs }
/// ```
#[lang = "bitxor"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} ^ {RHS}`"]
pub trait BitXor<RHS=Self> {
/// The resulting type after applying the `^` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -1134,6 +1142,7 @@ fn bitxor(self, other: $t) -> $t { self ^ other }
/// ```
#[lang = "shl"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} << {RHS}`"]
pub trait Shl<RHS> {
/// The resulting type after applying the `<<` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -1237,6 +1246,7 @@ macro_rules! shl_impl_all {
/// ```
#[lang = "shr"]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} >> {RHS}`"]
pub trait Shr<RHS> {
/// The resulting type after applying the `>>` operator
#[stable(feature = "rust1", since = "1.0.0")]
@ -1321,6 +1331,7 @@ macro_rules! shr_impl_all {
/// ```
#[lang = "add_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} += {Rhs}`"]
pub trait AddAssign<Rhs=Self> {
/// The method for the `+=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1377,6 +1388,7 @@ fn add_assign(&mut self, other: $t) { *self += other }
/// ```
#[lang = "sub_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} -= {Rhs}`"]
pub trait SubAssign<Rhs=Self> {
/// The method for the `-=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1422,6 +1434,7 @@ fn sub_assign(&mut self, other: $t) { *self -= other }
/// ```
#[lang = "mul_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} *= {Rhs}`"]
pub trait MulAssign<Rhs=Self> {
/// The method for the `*=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1467,6 +1480,7 @@ fn mul_assign(&mut self, other: $t) { *self *= other }
/// ```
#[lang = "div_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} /= {Rhs}`"]
pub trait DivAssign<Rhs=Self> {
/// The method for the `/=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1511,6 +1525,7 @@ fn div_assign(&mut self, other: $t) { *self /= other }
/// ```
#[lang = "rem_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} %= {Rhs}`"]
pub trait RemAssign<Rhs=Self> {
/// The method for the `%=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1597,6 +1612,7 @@ fn rem_assign(&mut self, other: $t) { *self %= other }
/// ```
#[lang = "bitand_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} &= {Rhs}`"]
pub trait BitAndAssign<Rhs=Self> {
/// The method for the `&=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1641,6 +1657,7 @@ fn bitand_assign(&mut self, other: $t) { *self &= other }
/// ```
#[lang = "bitor_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} |= {Rhs}`"]
pub trait BitOrAssign<Rhs=Self> {
/// The method for the `|=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1685,6 +1702,7 @@ fn bitor_assign(&mut self, other: $t) { *self |= other }
/// ```
#[lang = "bitxor_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} ^= {Rhs}`"]
pub trait BitXorAssign<Rhs=Self> {
/// The method for the `^=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1729,6 +1747,7 @@ fn bitxor_assign(&mut self, other: $t) { *self ^= other }
/// ```
#[lang = "shl_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} <<= {Rhs}`"]
pub trait ShlAssign<Rhs> {
/// The method for the `<<=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]
@ -1794,6 +1813,7 @@ macro_rules! shl_assign_impl_all {
/// ```
#[lang = "shr_assign"]
#[stable(feature = "op_assign_traits", since = "1.8.0")]
#[rustc_on_unimplemented = "no implementation for `{Self} >>= {Rhs}`"]
pub trait ShrAssign<Rhs=Self> {
/// The method for the `>>=` operator
#[stable(feature = "op_assign_traits", since = "1.8.0")]

20
src/librustc/traits/error_reporting.rs
View File

@ -524,15 +524,8 @@ pub fn report_selection_error(&self,
"the trait bound `{}` is not satisfied{}",
trait_ref.to_predicate(),
post_message);
err.span_label(span,
&format!("{}the trait `{}` is not \
implemented for `{}`",
pre_message,
trait_ref,
trait_ref.self_ty()));
// Try to report a help message
if !trait_ref.has_infer_types() &&
self.predicate_can_apply(trait_ref) {
// If a where-clause may be useful, remind the
@ -544,17 +537,21 @@ pub fn report_selection_error(&self,
// which is somewhat confusing.
err.help(&format!("consider adding a `where {}` bound",
trait_ref.to_predicate()));
} else if let Some(s) = self.on_unimplemented_note(trait_ref,
obligation) {
} else if let Some(s) = self.on_unimplemented_note(trait_ref, obligation) {
// If it has a custom "#[rustc_on_unimplemented]"
// error message, let's display it!
err.note(&s);
} else {
// If we can't show anything useful, try to find
// similar impls.
// Can't show anything else useful, try to find similar impls.
let impl_candidates = self.find_similar_impl_candidates(trait_ref);
self.report_similar_impl_candidates(impl_candidates, &mut err);
}
err.span_label(span,
&format!("{}the trait `{}` is not implemented for `{}`",
pre_message,
trait_ref,
trait_ref.self_ty()));
err
}
@ -997,3 +994,4 @@ fn suggest_new_overflow_limit(&self, err: &mut DiagnosticBuilder) {
suggested_limit));
}
}

2
src/test/compile-fail/impl-trait/equality.rs → src/test/ui/impl-trait/equality.rs
View File

@ -32,7 +32,7 @@ fn sum_to(n: u32) -> impl Foo {
0
} else {
n + sum_to(n - 1)
//~^ ERROR the trait bound `u32: std::ops::Add<impl Foo>` is not satisfied
//~^ ERROR no implementation for `u32 + impl Foo`
}
}

55
src/test/ui/impl-trait/equality.stderr Normal file
View File

@ -0,0 +1,55 @@
error[E0308]: mismatched types
--> $DIR/equality.rs:25:5
|
25 | 0_u32
| ^^^^^ expected i32, found u32
|
= note: expected type `i32`
found type `u32`
error[E0277]: the trait bound `u32: std::ops::Add<impl Foo>` is not satisfied
--> $DIR/equality.rs:34:9
|
34 | n + sum_to(n - 1)
| ^^^^^^^^^^^^^^^^^ the trait `std::ops::Add<impl Foo>` is not implemented for `u32`
|
= note: no implementation for `u32 + impl Foo`
error[E0308]: mismatched types
--> $DIR/equality.rs:53:18
|
53 | let _: u32 = hide(0_u32);
| ^^^^^^^^^^^ expected u32, found anonymized type
|
= note: expected type `u32`
found type `impl Foo`
error[E0308]: mismatched types
--> $DIR/equality.rs:59:18
|
59 | let _: i32 = Leak::leak(hide(0_i32));
| ^^^^^^^^^^^^^^^^^^^^^^^ expected i32, found associated type
|
= note: expected type `i32`
found type `<impl Foo as Leak>::T`
error[E0308]: mismatched types
--> $DIR/equality.rs:66:10
|
66 | x = (x.1,
| ^^^ expected u32, found i32
|
= note: expected type `impl Foo` (u32)
found type `impl Foo` (i32)
error[E0308]: mismatched types
--> $DIR/equality.rs:69:10
|
69 | x.0);
| ^^^ expected i32, found u32
|
= note: expected type `impl Foo` (i32)
found type `impl Foo` (u32)
error: aborting due to 6 previous errors

18
src/test/ui/mismatched_types/binops.rs Normal file
View File

@ -0,0 +1,18 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
fn main() {
1 + Some(1);
2 as usize - Some(1);
3 * ();
4 / "";
5 < String::new();
6 == Ok(1);
}

58
src/test/ui/mismatched_types/binops.stderr Normal file
View File

@ -0,0 +1,58 @@
error[E0277]: the trait bound `{integer}: std::ops::Add<std::option::Option<{integer}>>` is not satisfied
--> $DIR/binops.rs:12:5
|
12 | 1 + Some(1);
| ^^^^^^^^^^^ the trait `std::ops::Add<std::option::Option<{integer}>>` is not implemented for `{integer}`
|
= note: no implementation for `{integer} + std::option::Option<{integer}>`
error[E0277]: the trait bound `usize: std::ops::Sub<std::option::Option<{integer}>>` is not satisfied
--> $DIR/binops.rs:13:5
|
13 | 2 as usize - Some(1);
| ^^^^^^^^^^^^^^^^^^^^ the trait `std::ops::Sub<std::option::Option<{integer}>>` is not implemented for `usize`
|
= note: no implementation for `usize - std::option::Option<{integer}>`
error[E0277]: the trait bound `{integer}: std::ops::Mul<()>` is not satisfied
--> $DIR/binops.rs:14:5
|
14 | 3 * ();
| ^^^^^^ the trait `std::ops::Mul<()>` is not implemented for `{integer}`
|
= note: no implementation for `{integer} * ()`
error[E0277]: the trait bound `{integer}: std::ops::Div<&str>` is not satisfied
--> $DIR/binops.rs:15:5
|
15 | 4 / "";
| ^^^^^^ the trait `std::ops::Div<&str>` is not implemented for `{integer}`
|
= note: no implementation for `{integer} / &str`
error[E0277]: the trait bound `{integer}: std::cmp::PartialEq<std::string::String>` is not satisfied
--> $DIR/binops.rs:16:5
|
16 | 5 < String::new();
| ^^^^^^^^^^^^^^^^^ the trait `std::cmp::PartialEq<std::string::String>` is not implemented for `{integer}`
|
= note: can't compare `{integer}` with `std::string::String`
error[E0277]: the trait bound `{integer}: std::cmp::PartialOrd<std::string::String>` is not satisfied
--> $DIR/binops.rs:16:5
|
16 | 5 < String::new();
| ^^^^^^^^^^^^^^^^^ the trait `std::cmp::PartialOrd<std::string::String>` is not implemented for `{integer}`
|
= note: can't compare `{integer}` with `std::string::String`
error[E0277]: the trait bound `{integer}: std::cmp::PartialEq<std::result::Result<{integer}, _>>` is not satisfied
--> $DIR/binops.rs:17:5
|
17 | 6 == Ok(1);
| ^^^^^^^^^^ the trait `std::cmp::PartialEq<std::result::Result<{integer}, _>>` is not implemented for `{integer}`
|
= note: can't compare `{integer}` with `std::result::Result<{integer}, _>`
error: aborting due to 7 previous errors

6
src/test/ui/span/multiline-span-simple.stderr
View File

@ -9,11 +9,7 @@ error[E0277]: the trait bound `u32: std::ops::Add<()>` is not satisfied
27 | | y),
| |______________^ ...ending here: the trait `std::ops::Add<()>` is not implemented for `u32`
|
= help: the following implementations were found:
<u32 as std::ops::Add>
<&'a u32 as std::ops::Add<u32>>
<u32 as std::ops::Add<&'a u32>>
<&'b u32 as std::ops::Add<&'a u32>>
= note: no implementation for `u32 + ()`
error: aborting due to previous error