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Print fn signature when there is closure argument type mismatch

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Fixes #42143.
E0281 is totally replaced by E0631. UI tests are updated accordingly.
This commit is contained in:
Wonwoo Choi 2017-09-23 10:15:30 +09:00
parent 3eb19bf9b1
commit 1bfbfb20a1
14 changed files with 245 additions and 119 deletions
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5
src/librustc/diagnostics.rs
View File

@ -1139,11 +1139,13 @@ already specify all requirements that will be used for every type parameter.
"##,
E0281: r##"
#### Note: this error code is no longer emitted by the compiler.
You tried to supply a type which doesn't implement some trait in a location
which expected that trait. This error typically occurs when working with
`Fn`-based types. Erroneous code example:
```compile_fail,E0281
```compile-fail
fn foo<F: Fn(usize)>(x: F) { }
fn main() {
@ -2086,5 +2088,6 @@ register_diagnostics! {
E0566, // conflicting representation hints
E0623, // lifetime mismatch where both parameters are anonymous regions
E0628, // generators cannot have explicit arguments
E0631, // type mismatch in closure arguments
E0637, // "'_" is not a valid lifetime bound
}

141
src/librustc/traits/error_reporting.rs
View File

@ -37,7 +37,7 @@ use rustc::lint::builtin::EXTRA_REQUIREMENT_IN_IMPL;
use std::fmt;
use syntax::ast;
use ty::{self, AdtKind, ToPredicate, ToPolyTraitRef, Ty, TyCtxt, TypeFoldable};
use ty::error::{ExpectedFound, TypeError};
use ty::error::ExpectedFound;
use ty::fast_reject;
use ty::fold::TypeFolder;
use ty::subst::Subst;
@ -711,7 +711,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
}
OutputTypeParameterMismatch(ref expected_trait_ref, ref actual_trait_ref, ref e) => {
OutputTypeParameterMismatch(ref expected_trait_ref, ref actual_trait_ref, _) => {
let expected_trait_ref = self.resolve_type_vars_if_possible(&*expected_trait_ref);
let actual_trait_ref = self.resolve_type_vars_if_possible(&*actual_trait_ref);
if actual_trait_ref.self_ty().references_error() {
@ -722,48 +722,31 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
self.tcx.hir.span_if_local(did)
});
if let &TypeError::TupleSize(ref expected_found) = e {
// Expected `|x| { }`, found `|x, y| { }`
self.report_arg_count_mismatch(span,
found_span,
expected_found.expected,
expected_found.found,
expected_trait_ty.is_closure())
} else if let &TypeError::Sorts(ref expected_found) = e {
let expected = if let ty::TyTuple(tys, _) = expected_found.expected.sty {
tys.len()
} else {
1
let self_ty_count =
match expected_trait_ref.skip_binder().substs.type_at(1).sty {
ty::TyTuple(ref tys, _) => tys.len(),
_ => 1,
};
let found = if let ty::TyTuple(tys, _) = expected_found.found.sty {
tys.len()
} else {
1
let arg_ty_count =
match actual_trait_ref.skip_binder().substs.type_at(1).sty {
ty::TyTuple(ref tys, _) => tys.len(),
_ => 1,
};
if expected != found {
// Expected `|| { }`, found `|x, y| { }`
// Expected `fn(x) -> ()`, found `|| { }`
self.report_arg_count_mismatch(span,
found_span,
expected,
found,
expected_trait_ty.is_closure())
} else {
self.report_type_argument_mismatch(span,
found_span,
expected_trait_ty,
expected_trait_ref,
actual_trait_ref,
e)
}
if self_ty_count == arg_ty_count {
self.report_closure_arg_mismatch(span,
found_span,
expected_trait_ref,
actual_trait_ref)
} else {
self.report_type_argument_mismatch(span,
found_span,
expected_trait_ty,
expected_trait_ref,
actual_trait_ref,
e)
// Expected `|| { }`, found `|x, y| { }`
// Expected `fn(x) -> ()`, found `|| { }`
self.report_arg_count_mismatch(
span,
found_span,
arg_ty_count,
self_ty_count,
expected_trait_ty.is_closure()
)
}
}
@ -784,31 +767,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
err.emit();
}
fn report_type_argument_mismatch(&self,
span: Span,
found_span: Option<Span>,
expected_ty: Ty<'tcx>,
expected_ref: ty::PolyTraitRef<'tcx>,
found_ref: ty::PolyTraitRef<'tcx>,
type_error: &TypeError<'tcx>)
-> DiagnosticBuilder<'tcx>
{
let mut err = struct_span_err!(self.tcx.sess, span, E0281,
"type mismatch: `{}` implements the trait `{}`, but the trait `{}` is required",
expected_ty,
expected_ref,
found_ref);
err.span_label(span, format!("{}", type_error));
if let Some(sp) = found_span {
err.span_label(span, format!("requires `{}`", found_ref));
err.span_label(sp, format!("implements `{}`", expected_ref));
}
err
}
fn report_arg_count_mismatch(&self,
span: Span,
found_span: Option<Span>,
@ -837,6 +795,57 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
err
}
fn report_closure_arg_mismatch(&self,
span: Span,
found_span: Option<Span>,
expected_ref: ty::PolyTraitRef<'tcx>,
found: ty::PolyTraitRef<'tcx>)
-> DiagnosticBuilder<'tcx>
{
fn build_fn_sig_string<'a, 'gcx, 'tcx>(tcx: ty::TyCtxt<'a, 'gcx, 'tcx>,
trait_ref: &ty::TraitRef<'tcx>) -> String {
let inputs = trait_ref.substs.type_at(1);
let sig = if let ty::TyTuple(inputs, _) = inputs.sty {
tcx.mk_fn_sig(
inputs.iter().map(|&x| x),
tcx.mk_infer(ty::TyVar(ty::TyVid { index: 0 })),
false,
hir::Unsafety::Normal,
::syntax::abi::Abi::Rust
)
} else {
tcx.mk_fn_sig(
::std::iter::once(inputs),
tcx.mk_infer(ty::TyVar(ty::TyVid { index: 0 })),
false,
hir::Unsafety::Normal,
::syntax::abi::Abi::Rust
)
};
format!("{}", ty::Binder(sig))
}
let argument_is_closure = expected_ref.skip_binder().substs.type_at(0).is_closure();
let mut err = struct_span_err!(self.tcx.sess, span, E0631,
"type mismatch in {} arguments",
if argument_is_closure { "closure" } else { "function" });
let found_str = format!(
"expected signature of `{}`",
build_fn_sig_string(self.tcx, found.skip_binder())
);
err.span_label(span, found_str);
let found_span = found_span.unwrap_or(span);
let expected_str = format!(
"found signature of `{}`",
build_fn_sig_string(self.tcx, expected_ref.skip_binder())
);
err.span_label(found_span, expected_str);
err
}
}
impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {

6
src/librustc/util/ppaux.rs
View File

@ -676,6 +676,12 @@ impl<'tcx> fmt::Display for ty::Binder<ty::TraitRef<'tcx>> {
}
}
impl<'tcx> fmt::Display for ty::Binder<ty::FnSig<'tcx>> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
ty::tls::with(|tcx| in_binder(f, tcx, self, tcx.lift(self)))
}
}
impl<'tcx> fmt::Display for ty::Binder<ty::TraitPredicate<'tcx>> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
ty::tls::with(|tcx| in_binder(f, tcx, self, tcx.lift(self)))

13
src/test/ui/mismatched_types/E0281.stderr
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@ -1,13 +0,0 @@
error[E0281]: type mismatch: `[closure@$DIR/E0281.rs:14:9: 14:24]` implements the trait `std::ops::Fn<(std::string::String,)>`, but the trait `std::ops::Fn<(usize,)>` is required
--> $DIR/E0281.rs:14:5
|
14 | foo(|y: String| { });
| ^^^ --------------- implements `std::ops::Fn<(std::string::String,)>`
| |
| expected usize, found struct `std::string::String`
| requires `std::ops::Fn<(usize,)>`
|
= note: required by `foo`
error: aborting due to previous error

20
src/test/ui/mismatched_types/E0281.rs → src/test/ui/mismatched_types/E0631.rs
View File

@ -8,18 +8,14 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
fn foo<F: Fn(usize)>(x: F) { }
#![feature(unboxed_closures)]
fn foo<F: Fn(usize)>(_: F) {}
fn bar<F: Fn<usize>>(_: F) {}
fn main() {
foo(|y: String| { });
//~^ ERROR E0281
//~| ERROR E0281
//~| NOTE implements
//~| NOTE implements
//~| NOTE requires
//~| NOTE requires
//~| NOTE expected usize, found struct `std::string::String`
//~| NOTE expected usize, found struct `std::string::String`
//~| NOTE required by `foo`
//~| NOTE required by `foo`
fn f(_: u64) {}
foo(|_: isize| {});
bar(|_: isize| {});
foo(f);
bar(f);
}

44
src/test/ui/mismatched_types/E0631.stderr Normal file
View File

@ -0,0 +1,44 @@
error[E0631]: type mismatch in closure arguments
--> $DIR/E0631.rs:17:5
|
17 | foo(|_: isize| {});
| ^^^ ------------- found signature of `fn(isize) -> _`
| |
| expected signature of `fn(usize) -> _`
|
= note: required by `foo`
error[E0631]: type mismatch in closure arguments
--> $DIR/E0631.rs:18:5
|
18 | bar(|_: isize| {});
| ^^^ ------------- found signature of `fn(isize) -> _`
| |
| expected signature of `fn(usize) -> _`
|
= note: required by `bar`
error[E0631]: type mismatch in function arguments
--> $DIR/E0631.rs:19:5
|
19 | foo(f);
| ^^^
| |
| expected signature of `fn(usize) -> _`
| found signature of `fn(u64) -> _`
|
= note: required by `foo`
error[E0631]: type mismatch in function arguments
--> $DIR/E0631.rs:20:5
|
20 | bar(f);
| ^^^
| |
| expected signature of `fn(usize) -> _`
| found signature of `fn(u64) -> _`
|
= note: required by `bar`
error: aborting due to 4 previous errors

4
src/test/ui/mismatched_types/closure-arg-count.rs
View File

@ -8,8 +8,12 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(unboxed_closures)]
fn f<F: Fn<usize>>(_: F) {}
fn main() {
[1, 2, 3].sort_by(|| panic!());
[1, 2, 3].sort_by(|tuple| panic!());
[1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
f(|| panic!());
}

28
src/test/ui/mismatched_types/closure-arg-count.stderr
View File

@ -1,35 +1,45 @@
error[E0593]: closure takes 0 arguments but 2 arguments are required
--> $DIR/closure-arg-count.rs:12:15
--> $DIR/closure-arg-count.rs:15:15
|
12 | [1, 2, 3].sort_by(|| panic!());
15 | [1, 2, 3].sort_by(|| panic!());
| ^^^^^^^ ----------- takes 0 arguments
| |
| expected closure that takes 2 arguments
error[E0593]: closure takes 1 argument but 2 arguments are required
--> $DIR/closure-arg-count.rs:13:15
--> $DIR/closure-arg-count.rs:16:15
|
13 | [1, 2, 3].sort_by(|tuple| panic!());
16 | [1, 2, 3].sort_by(|tuple| panic!());
| ^^^^^^^ ---------------- takes 1 argument
| |
| expected closure that takes 2 arguments
error[E0308]: mismatched types
--> $DIR/closure-arg-count.rs:14:24
--> $DIR/closure-arg-count.rs:17:24
|
14 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
17 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
| ^^^^^^^^^^^^^^^ expected &{integer}, found tuple
|
= note: expected type `&{integer}`
found type `(_, _)`
error[E0593]: closure takes 1 argument but 2 arguments are required
--> $DIR/closure-arg-count.rs:14:15
--> $DIR/closure-arg-count.rs:17:15
|
14 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
17 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
| ^^^^^^^ -------------------------- takes 1 argument
| |
| expected closure that takes 2 arguments
error: aborting due to 4 previous errors
error[E0593]: closure takes 0 arguments but 1 argument is required
--> $DIR/closure-arg-count.rs:18:5
|
18 | f(|| panic!());
| ^ ----------- takes 0 arguments
| |
| expected closure that takes 1 argument
|
= note: required by `f`
error: aborting due to 5 previous errors

21
src/test/ui/mismatched_types/closure-arg-type-mismatch.rs Normal file
View File

@ -0,0 +1,21 @@
// 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() {
let a = [(1u32, 2u32)];
a.iter().map(|_: (u32, u32)| 45);
a.iter().map(|_: &(u16, u16)| 45);
a.iter().map(|_: (u16, u16)| 45);
}
fn baz<F: Fn(*mut &u32)>(_: F) {}
fn _test<'a>(f: fn(*mut &'a u32)) {
baz(f);
}

45
src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr Normal file
View File

@ -0,0 +1,45 @@
error[E0631]: type mismatch in closure arguments
--> $DIR/closure-arg-type-mismatch.rs:13:14
|
13 | a.iter().map(|_: (u32, u32)| 45);
| ^^^ ------------------ found signature of `fn((u32, u32)) -> _`
| |
| expected signature of `fn(&(u32, u32)) -> _`
error[E0631]: type mismatch in closure arguments
--> $DIR/closure-arg-type-mismatch.rs:14:14
|
14 | a.iter().map(|_: &(u16, u16)| 45);
| ^^^ ------------------- found signature of `for<'r> fn(&'r (u16, u16)) -> _`
| |
| expected signature of `fn(&(u32, u32)) -> _`
error[E0631]: type mismatch in closure arguments
--> $DIR/closure-arg-type-mismatch.rs:15:14
|
15 | a.iter().map(|_: (u16, u16)| 45);
| ^^^ ------------------ found signature of `fn((u16, u16)) -> _`
| |
| expected signature of `fn(&(u32, u32)) -> _`
error[E0631]: type mismatch in function arguments
--> $DIR/closure-arg-type-mismatch.rs:20:5
|
20 | baz(f);
| ^^^
| |
| expected signature of `for<'r> fn(*mut &'r u32) -> _`
| found signature of `fn(*mut &'a u32) -> _`
|
= note: required by `baz`
error[E0271]: type mismatch resolving `for<'r> <fn(*mut &'a u32) as std::ops::FnOnce<(*mut &'r u32,)>>::Output == ()`
--> $DIR/closure-arg-type-mismatch.rs:20:5
|
20 | baz(f);
| ^^^ expected bound lifetime parameter, found concrete lifetime
|
= note: required by `baz`
error: aborting due to 5 previous errors

7
src/test/ui/mismatched_types/closure-mismatch.stderr
View File

@ -7,14 +7,13 @@ error[E0271]: type mismatch resolving `for<'r> <[closure@$DIR/closure-mismatch.r
= note: required because of the requirements on the impl of `Foo` for `[closure@$DIR/closure-mismatch.rs:18:9: 18:15]`
= note: required by `baz`
error[E0281]: type mismatch: `[closure@$DIR/closure-mismatch.rs:18:9: 18:15]` implements the trait `std::ops::Fn<(_,)>`, but the trait `for<'r> std::ops::Fn<(&'r (),)>` is required
error[E0631]: type mismatch in closure arguments
--> $DIR/closure-mismatch.rs:18:5
|
18 | baz(|_| ());
| ^^^ ------ implements `std::ops::Fn<(_,)>`
| ^^^ ------ found signature of `fn(_) -> _`
| |
| expected concrete lifetime, found bound lifetime parameter
| requires `for<'r> std::ops::Fn<(&'r (),)>`
| expected signature of `for<'r> fn(&'r ()) -> _`
|
= note: required because of the requirements on the impl of `Foo` for `[closure@$DIR/closure-mismatch.rs:18:9: 18:15]`
= note: required by `baz`

14
src/test/ui/mismatched_types/fn-variance-1.stderr
View File

@ -1,16 +1,22 @@
error[E0281]: type mismatch: `fn(&mut isize) {takes_mut}` implements the trait `for<'r> std::ops::FnOnce<(&'r mut isize,)>`, but the trait `std::ops::FnOnce<(&{integer},)>` is required
error[E0631]: type mismatch in function arguments
--> $DIR/fn-variance-1.rs:21:5
|
21 | apply(&3, takes_mut);
| ^^^^^ types differ in mutability
| ^^^^^
| |
| expected signature of `fn(&{integer}) -> _`
| found signature of `for<'r> fn(&'r mut isize) -> _`
|
= note: required by `apply`
error[E0281]: type mismatch: `fn(&isize) {takes_imm}` implements the trait `for<'r> std::ops::FnOnce<(&'r isize,)>`, but the trait `std::ops::FnOnce<(&mut {integer},)>` is required
error[E0631]: type mismatch in function arguments
--> $DIR/fn-variance-1.rs:27:5
|
27 | apply(&mut 3, takes_imm);
| ^^^^^ types differ in mutability
| ^^^^^
| |
| expected signature of `fn(&mut {integer}) -> _`
| found signature of `for<'r> fn(&'r isize) -> _`
|
= note: required by `apply`

7
src/test/ui/mismatched_types/issue-36053-2.stderr
View File

@ -8,14 +8,13 @@ error[E0599]: no method named `count` found for type `std::iter::Filter<std::ite
`std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
`&mut std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
error[E0281]: type mismatch: `[closure@$DIR/issue-36053-2.rs:17:39: 17:53]` implements the trait `for<'r> std::ops::FnMut<(&'r str,)>`, but the trait `for<'r> std::ops::FnMut<(&'r &str,)>` is required
error[E0631]: type mismatch in closure arguments
--> $DIR/issue-36053-2.rs:17:32
|
17 | once::<&str>("str").fuse().filter(|a: &str| true).count();
| ^^^^^^ -------------- implements `for<'r> std::ops::FnMut<(&'r str,)>`
| ^^^^^^ -------------- found signature of `for<'r> fn(&'r str) -> _`
| |
| expected &str, found str
| requires `for<'r> std::ops::FnMut<(&'r &str,)>`
| expected signature of `for<'r> fn(&'r &str) -> _`
error: aborting due to 2 previous errors

9
src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr
View File

@ -1,14 +1,11 @@
error[E0281]: type mismatch: `[closure@$DIR/unboxed-closures-vtable-mismatch.rs:22:23: 22:73]` implements the trait `std::ops::FnMut<(usize, isize)>`, but the trait `std::ops::FnMut<(isize, isize)>` is required
error[E0631]: type mismatch in closure arguments
--> $DIR/unboxed-closures-vtable-mismatch.rs:25:13
|
22 | let f = to_fn_mut(|x: usize, y: isize| -> isize { (x as isize) + y });
| -------------------------------------------------- implements `std::ops::FnMut<(usize, isize)>`
| -------------------------------------------------- found signature of `fn(usize, isize) -> _`
...
25 | let z = call_it(3, f);
| ^^^^^^^
| |
| expected isize, found usize
| requires `std::ops::FnMut<(isize, isize)>`
| ^^^^^^^ expected signature of `fn(isize, isize) -> _`
|
= note: required by `call_it`