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auto merge of #18264 : jakub-/rust/var-ids-in-error-messages, r=nikomatsakis

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This PR aims to improve the readability of diagnostic messages that involve unresolved type variables. Currently, messages like the following:

```rust
mismatched types: expected `core::result::Result<uint,()>`, found `core::option::Option<<generic #1>>`
<anon>:6     let a: Result<uint, ()> = None;
                                       ^~~~
mismatched types: expected `&mut <generic #2>`, found `uint`
<anon>:7     f(42u);
               ^~~
```

tend to appear unapproachable to new users. [0] While specific type var IDs are valuable in
diagnostics that deal with more than one such variable, in practice many messages
only mention one. In those cases, leaving out the specific number makes the messages
slightly less terrifying.

```rust
mismatched types: expected `core::result::Result<uint, ()>`, found `core::option::Option<_>`
<anon>:6     let a: Result<uint, ()> = None;
                                       ^~~~
mismatched types: expected `&mut _`, found `uint`
<anon>:7     f(42u);
               ^~~
```

As you can see, I also tweaked the aesthetics slightly by changing type variables to use the type hole syntax _. For integer variables, the syntax used is:

```rust
mismatched types: expected `core::result::Result<uint, ()>`, found `core::option::Option<_#1i>`
<anon>:6     let a: Result<uint, ()> = Some(1);
```

and float variables:

```rust
mismatched types: expected `core::result::Result<uint, ()>`, found `core::option::Option<_#1f>`
<anon>:6     let a: Result<uint, ()> = Some(0.5);
```

[0] https://twitter.com/coda/status/517713085465772032

Closes https://github.com/rust-lang/rust/issues/2632.
Closes https://github.com/rust-lang/rust/issues/3404.
Closes https://github.com/rust-lang/rust/issues/18426.
This commit is contained in:
bors 2014-10-31 11:16:44 +00:00
commit 82045ca360
29 changed files with 241 additions and 195 deletions
Download patch file Download diff file Expand all files Collapse all files

4
src/test/compile-fail/array-not-vector.rs
View file

@ -9,8 +9,8 @@
// except according to those terms.
fn main() {
let _x: int = [1i, 2, 3]; //~ ERROR expected int, found array
let _x: int = [1i, 2, 3]; //~ ERROR expected int, found array of 3 elements
let x: &[int] = &[1, 2, 3];
let _y: &int = x; //~ ERROR expected int, found unsized array
let _y: &int = x; //~ ERROR expected int, found slice
}

8
src/test/compile-fail/explicit-self-lifetime-mismatch.rs
View file

@ -16,10 +16,10 @@ struct Foo<'a,'b> {
impl<'a,'b> Foo<'a,'b> {
// The number of errors is related to the way invariance works.
fn bar(self: Foo<'b,'a>) {}
//~^ ERROR mismatched types: expected `Foo<'a,'b>`, found `Foo<'b,'a>`
//~^^ ERROR mismatched types: expected `Foo<'a,'b>`, found `Foo<'b,'a>`
//~^^^ ERROR mismatched types: expected `Foo<'b,'a>`, found `Foo<'a,'b>`
//~^^^^ ERROR mismatched types: expected `Foo<'b,'a>`, found `Foo<'a,'b>`
//~^ ERROR mismatched types: expected `Foo<'a, 'b>`, found `Foo<'b, 'a>`
//~^^ ERROR mismatched types: expected `Foo<'a, 'b>`, found `Foo<'b, 'a>`
//~^^^ ERROR mismatched types: expected `Foo<'b, 'a>`, found `Foo<'a, 'b>`
//~^^^^ ERROR mismatched types: expected `Foo<'b, 'a>`, found `Foo<'a, 'b>`
}
fn main() {}

6
src/test/compile-fail/generic-type-params-name-repr.rs
View file

@ -29,13 +29,13 @@ fn main() {
// Including cases where the default is using previous type params.
let _: HashMap<String, int> = ();
//~^ ERROR mismatched types: expected `HashMap<collections::string::String,int>`, found `()`
//~^ ERROR mismatched types: expected `HashMap<collections::string::String, int>`, found `()`
let _: HashMap<String, int, Hash<String>> = ();
//~^ ERROR mismatched types: expected `HashMap<collections::string::String,int>`, found `()`
//~^ ERROR mismatched types: expected `HashMap<collections::string::String, int>`, found `()`
// But not when there's a different type in between.
let _: Foo<A, int, C> = ();
//~^ ERROR mismatched types: expected `Foo<A,int>`, found `()`
//~^ ERROR mismatched types: expected `Foo<A, int>`, found `()`
// And don't print <> at all when there's just defaults.
let _: Foo<A, B, C> = ();

15
src/test/compile-fail/integral-variable-unification-error.rs Normal file
View file

@ -0,0 +1,15 @@
// Copyright 2014 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() {
let mut x = 2;
x = 5.0;
//~^ ERROR expected `_`, found `_` (expected integral variable, found floating-point variable)
}

21
src/test/compile-fail/issue-13482-2.rs Normal file
View file

@ -0,0 +1,21 @@
// Copyright 2014 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.
// compile-flags:-Z verbose
fn main() {
let x = [1,2];
let y = match x {
[] => None,
//~^ ERROR types: expected `[_#0i, ..2]`, found `[_#7, ..0]`
// (expected array of 2 elements, found array of 0 elements)
[a,_] => Some(a)
};
}

4
src/test/compile-fail/issue-13482.rs
View file

@ -12,8 +12,8 @@ fn main() {
let x = [1,2];
let y = match x {
[] => None,
//~^ ERROR mismatched types: expected `[<generic integer #0>, ..2]`, found `[<generic #7>, ..0]`
// (expected array, found array)
//~^ ERROR types: expected `[_, ..2]`, found `[_, ..0]`
// (expected array of 2 elements, found array of 0 elements)
[a,_] => Some(a)
};
}

2
src/test/compile-fail/issue-16338.rs
View file

@ -12,7 +12,7 @@ use std::raw::Slice;
fn main() {
let Slice { data: data, len: len } = "foo";
//~^ ERROR mismatched types: expected `&str`, found `core::raw::Slice<<generic #3>>`
//~^ ERROR mismatched types: expected `&str`, found `core::raw::Slice<_>`
// (expected &-ptr, found struct core::raw::Slice)
}

2
src/test/compile-fail/issue-16401.rs
View file

@ -13,7 +13,7 @@ use std::raw::Slice;
fn main() {
match () {
Slice { data: data, len: len } => (),
//~^ ERROR mismatched types: expected `()`, found `core::raw::Slice<<generic #3>>`
//~^ ERROR mismatched types: expected `()`, found `core::raw::Slice<_>`
// (expected (), found struct core::raw::Slice)
_ => unreachable!()
}

4
src/test/compile-fail/issue-3680.rs
View file

@ -11,7 +11,7 @@
fn main() {
match None {
Err(_) => ()
//~^ ERROR mismatched types: expected `core::option::Option<<generic #1>>`
// , found `core::result::Result<<generic #2>,<generic #3>>`
//~^ ERROR mismatched types: expected `core::option::Option<_>`
// , found `core::result::Result<_, _>`
}
}

2
src/test/compile-fail/issue-4201.rs
View file

@ -12,7 +12,7 @@ fn main() {
let a = if true {
0
} else if false {
//~^ ERROR if may be missing an else clause: expected `()`, found `<generic integer #1>`
//~^ ERROR if may be missing an else clause: expected `()`, found `_`
1
};
}

2
src/test/compile-fail/issue-4968.rs
View file

@ -13,6 +13,6 @@
const A: (int,int) = (4,2);
fn main() {
match 42 { A => () }
//~^ ERROR mismatched types: expected `<generic integer #0>`, found `(int,int)`
//~^ ERROR mismatched types: expected `_`, found `(int, int)`
// (expected integral variable, found tuple)
}

20
src/test/compile-fail/issue-5100.rs
View file

@ -13,32 +13,32 @@ enum A { B, C }
fn main() {
match (true, false) {
B => (),
//~^ ERROR mismatched types: expected `(bool,bool)`, found `A`
// (expected tuple, found enum A)
//~^ ERROR mismatched types: expected `(bool, bool)`, found `A` (expected tuple, found enum A)
_ => ()
}
match (true, false) {
(true, false, false) => ()
//~^ ERROR mismatched types: expected `(bool,bool)`,
// found `(<generic #7>,<generic #8>,<generic #9>)`
// (expected a tuple with 2 elements, found one with 3 elements)
//~^ ERROR mismatched types: expected `(bool, bool)`, found `(_, _, _)`
}
match (true, false) {
(true, false, false) => ()
//~^ ERROR (expected a tuple with 2 elements, found one with 3 elements)
}
match (true, false) {
box (true, false) => ()
//~^ ERROR mismatched types: expected `(bool,bool)`, found `Box<<generic #15>>`
// (expected tuple, found box)
//~^ ERROR mismatched types: expected `(bool, bool)`, found `Box<_>` (expected tuple, found box)
}
match (true, false) {
&(true, false) => ()
//~^ ERROR mismatched types: expected `(bool,bool)`, found `&<generic #21>`
// (expected tuple, found &-ptr)
//~^ ERROR mismatched types: expected `(bool, bool)`, found `&_` (expected tuple, found &-ptr)
}
let v = [('a', 'b') //~ ERROR expected function, found `(char,char)`
let v = [('a', 'b') //~ ERROR expected function, found `(char, char)`
('c', 'd'),
('e', 'f')];

2
src/test/compile-fail/issue-5500.rs
View file

@ -10,5 +10,5 @@
fn main() {
&panic!()
//~^ ERROR mismatched types: expected `()`, found `&<generic #2>` (expected (), found &-ptr)
//~^ ERROR mismatched types: expected `()`, found `&_` (expected (), found &-ptr)
}

2
src/test/compile-fail/issue-7092.rs
View file

@ -14,7 +14,7 @@ enum Whatever {
fn foo(x: Whatever) {
match x {
Some(field) =>
//~^ ERROR: mismatched types: expected `Whatever`, found `core::option::Option<<generic #3>>`
//~^ ERROR: mismatched types: expected `Whatever`, found `core::option::Option<_>`
field.access(), //~ ERROR the type of this value must be known in this context
}
}

6
src/test/compile-fail/issue-7867.rs
View file

@ -14,14 +14,14 @@ mod foo { pub fn bar() {} }
fn main() {
match (true, false) {
B => (), //~ ERROR expected `(bool,bool)`, found `A` (expected tuple, found enum A)
B => (), //~ ERROR expected `(bool, bool)`, found `A` (expected tuple, found enum A)
_ => ()
}
match &Some(42i) {
Some(x) => (), //~ ERROR expected `&core::option::Option<int>`,
// found `core::option::Option<<generic #4>>`
// found `core::option::Option<_>`
None => () //~ ERROR expected `&core::option::Option<int>`,
// found `core::option::Option<<generic #5>>`
// found `core::option::Option<_>`
}
}

2
src/test/compile-fail/map-types.rs
View file

@ -18,5 +18,5 @@ fn main() {
let x: Box<HashMap<int, int>> = box HashMap::new();
let x: Box<Map<int, int>> = x;
let y: Box<Map<uint, int>> = box x;
//~^ ERROR the trait `collections::Map<uint,int>` is not implemented
//~^ ERROR the trait `collections::Map<uint, int>` is not implemented
}

2
src/test/compile-fail/match-vec-mismatch-2.rs
View file

@ -11,6 +11,6 @@
fn main() {
match () {
[()] => { }
//~^ ERROR mismatched types: expected `()`, found `&[<generic #1>]` (expected (), found &-ptr)
//~^ ERROR mismatched types: expected `()`, found `&[_]` (expected (), found &-ptr)
}
}

2
src/test/compile-fail/repeat_count.rs
View file

@ -18,7 +18,7 @@ fn main() {
let c = [0, ..true]; //~ ERROR expected positive integer for repeat count, found boolean
//~^ ERROR: expected `uint`, found `bool`
let d = [0, ..0.5]; //~ ERROR expected positive integer for repeat count, found float
//~^ ERROR: expected `uint`, found `<generic float #0>`
//~^ ERROR: expected `uint`, found `_`
let e = [0, .."foo"]; //~ ERROR expected positive integer for repeat count, found string
//~^ ERROR: expected `uint`, found `&'static str`
let f = [0, ..-4];

2
src/test/compile-fail/slightly-nice-generic-literal-messages.rs
View file

@ -13,7 +13,7 @@ struct Foo<T,U>(T);
fn main() {
match Foo(1.1) {
1 => {}
//~^ ERROR expected `Foo<<generic float #0>,<generic #2>>`, found `<generic integer #0>`
//~^ ERROR expected `Foo<_, _>`, found `_`
}
}

2
src/test/compile-fail/suppressed-error.rs
View file

@ -10,6 +10,6 @@
fn main() {
let (x, y) = ();
//~^ ERROR types: expected `()`, found `(<generic #3>,<generic #4>)` (expected (), found tuple)
//~^ ERROR expected `()`, found `(_, _)` (expected (), found tuple)
return x;
}

3
src/test/compile-fail/tuple-arity-mismatch.rs
View file

@ -15,4 +15,7 @@ fn first((value, _): (int, f64)) -> int { value }
fn main() {
let y = first ((1,2.0,3));
//~^ ERROR expected a tuple with 2 elements, found one with 3 elements
let y = first ((1,));
//~^ ERROR expected `(int, f64)`, found `(int,)`
}

2
src/test/compile-fail/tuple-index-out-of-bounds.rs
View file

@ -22,5 +22,5 @@ fn main() {
tuple.0;
tuple.1;
tuple.2;
//~^ ERROR attempted out-of-bounds tuple index `2` on type `(int,int)`
//~^ ERROR attempted out-of-bounds tuple index `2` on type `(int, int)`
}

5
src/test/compile-fail/type-parameter-names.rs
View file

@ -11,6 +11,9 @@
// Test that we print out the names of type parameters correctly in
// our error messages.
fn foo<Foo, Bar>(x: Foo) -> Bar { x } //~ ERROR expected `Bar`, found `Foo`
fn foo<Foo, Bar>(x: Foo) -> Bar {
x
//~^ ERROR expected `Bar`, found `Foo` (expected type parameter, found a different type parameter)
}
fn main() {}

4
src/test/compile-fail/typeck_type_placeholder_mismatch.rs
View file

@ -19,11 +19,11 @@ pub fn main() {
fn test1() {
let x: Foo<_> = Bar::<uint>;
//~^ ERROR mismatched types: expected `Foo<<generic #0>>`, found `Bar<uint>`
//~^ ERROR mismatched types: expected `Foo<_>`, found `Bar<uint>`
let y: Foo<uint> = x;
}
fn test2() {
let x: Foo<_> = Bar::<uint>;
//~^ ERROR mismatched types: expected `Foo<<generic #0>>`, found `Bar<uint>`
//~^ ERROR mismatched types: expected `Foo<_>`, found `Bar<uint>`
}