diff --git a/src/test/compile-fail/E0281.rs b/src/test/ui/mismatched_types/E0281.rs
similarity index 100%
rename from src/test/compile-fail/E0281.rs
rename to src/test/ui/mismatched_types/E0281.rs
diff --git a/src/test/ui/mismatched_types/E0281.stderr b/src/test/ui/mismatched_types/E0281.stderr
new file mode 100644
index 00000000000..28a649d4c91
--- /dev/null
+++ b/src/test/ui/mismatched_types/E0281.stderr
@@ -0,0 +1,24 @@
+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
+  --> $DIR/E0281.rs:14:5
+   |
+14 |     foo(|y: String| { });
+   |     ^^^ --------------- implements `std::ops::Fn<(std::string::String,)>`
+   |     |
+   |     requires `std::ops::Fn<(usize,)>`
+   |     expected usize, found struct `std::string::String`
+   |
+   = note: required by `foo`
+
+error[E0281]: type mismatch: `[closure@$DIR/E0281.rs:14:9: 14:24]` implements the trait `std::ops::FnOnce<(std::string::String,)>`, but the trait `std::ops::FnOnce<(usize,)>` is required
+  --> $DIR/E0281.rs:14:5
+   |
+14 |     foo(|y: String| { });
+   |     ^^^ --------------- implements `std::ops::FnOnce<(std::string::String,)>`
+   |     |
+   |     requires `std::ops::FnOnce<(usize,)>`
+   |     expected usize, found struct `std::string::String`
+   |
+   = note: required by `foo`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/compile-fail/fn-variance-1.rs b/src/test/ui/mismatched_types/fn-variance-1.rs
similarity index 100%
rename from src/test/compile-fail/fn-variance-1.rs
rename to src/test/ui/mismatched_types/fn-variance-1.rs
diff --git a/src/test/ui/mismatched_types/fn-variance-1.stderr b/src/test/ui/mismatched_types/fn-variance-1.stderr
new file mode 100644
index 00000000000..120fb87cdc8
--- /dev/null
+++ b/src/test/ui/mismatched_types/fn-variance-1.stderr
@@ -0,0 +1,18 @@
+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
+  --> $DIR/fn-variance-1.rs:21:5
+   |
+21 |     apply(&3, takes_mut);
+   |     ^^^^^ types differ in mutability
+   |
+   = 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
+  --> $DIR/fn-variance-1.rs:27:5
+   |
+27 |     apply(&mut 3, takes_imm);
+   |     ^^^^^ types differ in mutability
+   |
+   = note: required by `apply`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/compile-fail/issue-36053-2.rs b/src/test/ui/mismatched_types/issue-36053-2.rs
similarity index 100%
rename from src/test/compile-fail/issue-36053-2.rs
rename to src/test/ui/mismatched_types/issue-36053-2.rs
diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr
new file mode 100644
index 00000000000..adc229aaacc
--- /dev/null
+++ b/src/test/ui/mismatched_types/issue-36053-2.stderr
@@ -0,0 +1,28 @@
+error: no method named `count` found for type `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:17:39: 17:53]>` in the current scope
+  --> $DIR/issue-36053-2.rs:17:55
+   |
+17 |     once::<&str>("str").fuse().filter(|a: &str| true).count();
+   |                                                       ^^^^^
+   |
+   = note: the method `count` exists but the following trait bounds were not satisfied: `[closure@$DIR/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`, `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
+  --> $DIR/issue-36053-2.rs:17:32
+   |
+17 |     once::<&str>("str").fuse().filter(|a: &str| true).count();
+   |                                ^^^^^^ -------------- implements `for<'r> std::ops::FnMut<(&'r str,)>`
+   |                                |
+   |                                requires `for<'r> std::ops::FnMut<(&'r &str,)>`
+   |                                expected &str, found str
+
+error[E0281]: type mismatch: `[closure@$DIR/issue-36053-2.rs:17:39: 17:53]` implements the trait `for<'r> std::ops::FnOnce<(&'r str,)>`, but the trait `for<'r> std::ops::FnOnce<(&'r &str,)>` is required
+  --> $DIR/issue-36053-2.rs:17:32
+   |
+17 |     once::<&str>("str").fuse().filter(|a: &str| true).count();
+   |                                ^^^^^^ -------------- implements `for<'r> std::ops::FnOnce<(&'r str,)>`
+   |                                |
+   |                                requires `for<'r> std::ops::FnOnce<(&'r &str,)>`
+   |                                expected &str, found str
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/compile-fail/unboxed-closures-vtable-mismatch.rs b/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.rs
similarity index 100%
rename from src/test/compile-fail/unboxed-closures-vtable-mismatch.rs
rename to src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.rs
diff --git a/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr b/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr
new file mode 100644
index 00000000000..e100520e561
--- /dev/null
+++ b/src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr
@@ -0,0 +1,30 @@
+error[E0281]: type mismatch: `[closure@$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
+  --> $DIR/unboxed-closures-vtable-mismatch.rs:25:13
+   |
+22 |     let f = to_fn_mut(|x: usize, y: isize| -> isize { (x as isize) + y });
+   |                       -------------------------------------------------- implements `std::ops::FnMut<(usize, isize)>`
+...
+25 |     let z = call_it(3, f);
+   |             ^^^^^^^
+   |             |
+   |             requires `std::ops::FnMut<(isize, isize)>`
+   |             expected isize, found usize
+   |
+   = note: required by `call_it`
+
+error[E0281]: type mismatch: `[closure@$DIR/unboxed-closures-vtable-mismatch.rs:22:23: 22:73]` implements the trait `std::ops::FnOnce<(usize, isize)>`, but the trait `std::ops::FnOnce<(isize, isize)>` is required
+  --> $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::FnOnce<(usize, isize)>`
+...
+25 |     let z = call_it(3, f);
+   |             ^^^^^^^
+   |             |
+   |             requires `std::ops::FnOnce<(isize, isize)>`
+   |             expected isize, found usize
+   |
+   = note: required by `call_it`
+
+error: aborting due to 2 previous errors
+