Print fn signature when there is closure argument type mismatch

Fixes #42143.
E0281 is totally replaced by E0631. UI tests are updated accordingly.

11 files changed, 160 insertions, 52 deletions

diff --git a/src/test/ui/mismatched_types/E0281.stderr b/src/test/ui/mismatched_types/E0281.stderr
deleted file mode 100644
index 744e8c30939..00000000000
--- a/src/test/ui/mismatched_types/E0281.stderr
+++ /dev/null
@@ -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
-
diff --git a/src/test/ui/mismatched_types/E0281.rs b/src/test/ui/mismatched_types/E0631.rs
index abb66c99fab..e28f15ab0b6 100644
--- a/src/test/ui/mismatched_types/E0281.rs
+++ b/src/test/ui/mismatched_types/E0631.rs
@@ -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);
 }
diff --git a/src/test/ui/mismatched_types/E0631.stderr b/src/test/ui/mismatched_types/E0631.stderr
new file mode 100644
index 00000000000..235e7a10063
--- /dev/null
+++ b/src/test/ui/mismatched_types/E0631.stderr
@@ -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
+
diff --git a/src/test/ui/mismatched_types/closure-arg-count.rs b/src/test/ui/mismatched_types/closure-arg-count.rs
index 284f82d86eb..f94471a73ca 100644
--- a/src/test/ui/mismatched_types/closure-arg-count.rs
+++ b/src/test/ui/mismatched_types/closure-arg-count.rs
@@ -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!());
 }
diff --git a/src/test/ui/mismatched_types/closure-arg-count.stderr b/src/test/ui/mismatched_types/closure-arg-count.stderr
index ca71154e872..3031a77b1e8 100644
--- a/src/test/ui/mismatched_types/closure-arg-count.stderr
+++ b/src/test/ui/mismatched_types/closure-arg-count.stderr
@@ -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
 
diff --git a/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs b/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs
new file mode 100644
index 00000000000..aa9dba4c3f4
--- /dev/null
+++ b/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs
@@ -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);
+}
diff --git a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
new file mode 100644
index 00000000000..866a024ab08
--- /dev/null
+++ b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
@@ -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 == ()`
+  --> $DIR/closure-arg-type-mismatch.rs:20:5
+   |
+20 |     baz(f);
+   |     ^^^ expected bound lifetime parameter, found concrete lifetime
+   |
+   = note: required by `baz`
+
+error: aborting due to 5 previous errors
+
diff --git a/src/test/ui/mismatched_types/closure-mismatch.stderr b/src/test/ui/mismatched_types/closure-mismatch.stderr
index d928a6a0a8e..a54fd118cc5 100644
--- a/src/test/ui/mismatched_types/closure-mismatch.stderr
+++ b/src/test/ui/mismatched_types/closure-mismatch.stderr
@@ -7,14 +7,13 @@ error[E0271]: type mismatch resolving `for<'r> <[closure@$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`
diff --git a/src/test/ui/mismatched_types/fn-variance-1.stderr b/src/test/ui/mismatched_types/fn-variance-1.stderr
index 120fb87cdc8..09a90ef3d6b 100644
--- a/src/test/ui/mismatched_types/fn-variance-1.stderr
+++ b/src/test/ui/mismatched_types/fn-variance-1.stderr
@@ -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`
 
diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr
index e2e2019307f..71a3a0a5714 100644
--- a/src/test/ui/mismatched_types/issue-36053-2.stderr
+++ b/src/test/ui/mismatched_types/issue-36053-2.stderr
@@ -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
 
diff --git a/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr b/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr
index f14e711b23a..59883649280 100644
--- a/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr
+++ b/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr
@@ -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`