Auto merge of rust-lang#59044 - petrochenkov:uiui, r=davidtwco

Filter away test annotations from UI test output

If you worked with UI tests for some time you could notice one issue affecting their readability and also readability of diffs when the tests change.
Look at the output of this test.
```rust
fn main() {
    let 1 = 2; //~ ERROR refutable pattern in local binding
}
```
```
error[E0005]: refutable pattern in local binding: `-2147483648i32..=0i32` not covered
 --> src/main.rs:2:9
  |
2 |     let 1 = 2; //~ ERROR refutable pattern in local binding
  |         ^ pattern `-2147483648i32..=0i32` not covered

error: aborting due to previous error

For more information about this error, try `rustc --explain E0005`.
```
You can see that the "refutable pattern in local binding" is duplicated.
One instance is the actual error, and the second instance is the expected error annotation.
This annotation is useful in the test input, but in the output it clutters the text and makes it harder to see what text refers to actual errors and what is just comments, especially if there are many errors in a single test file.

@estebank [reported](rust-lang#57379 (comment)) using the next trick to avoid the clutter
```rust
fn main() {
    let 1 = 2;
    //~^ ERROR refutable pattern in local binding
}
```
```
error[E0005]: refutable pattern in local binding: `-2147483648i32..=0i32` not covered
 --> src/main.rs:2:9
  |
2 |     let 1 = 2;
  |         ^ pattern `-2147483648i32..=0i32` not covered

error: aborting due to previous error

For more information about this error, try `rustc --explain E0005`.
```
, i.e. using `//~^` and placing the annotation one line below will remove the annotation from the output.

However, this doesn't always works (consider errors with multi-line spans), and shouldn't be necessary in general!
`compiletest` could automatically filter away its own annotations from the output instead.
This is exactly what this PR does.

r? @davidtwco

Author: bors

src/test/rustdoc-ui/deny-intra-link-resolution-failure.stderr

@@ -1,7 +1,7 @@
 error: `[v2]` cannot be resolved, ignoring it...
   --> $DIR/deny-intra-link-resolution-failure.rs:3:6
    |
-LL | /// [v2] //~ ERROR
+LL | /// [v2]
    |      ^^ cannot be resolved, ignoring
    |
 note: lint level defined here

src/test/rustdoc-ui/deny-missing-docs-crate.stderr

@@ -1,21 +1,21 @@
 error: missing documentation for crate
   --> $DIR/deny-missing-docs-crate.rs:1:1
    |
-LL | / #![deny(missing_docs)] //~ ERROR
+LL | / #![deny(missing_docs)]
 LL | |
-LL | | pub struct Foo; //~ ERROR
+LL | | pub struct Foo;
    | |_______________^
    |
 note: lint level defined here
   --> $DIR/deny-missing-docs-crate.rs:1:9
    |
-LL | #![deny(missing_docs)] //~ ERROR
+LL | #![deny(missing_docs)]
    |         ^^^^^^^^^^^^
 
 error: missing documentation for a struct
   --> $DIR/deny-missing-docs-crate.rs:3:1
    |
-LL | pub struct Foo; //~ ERROR
+LL | pub struct Foo;
    | ^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors

src/test/rustdoc-ui/deny-missing-docs-macro.stderr

@@ -1,7 +1,7 @@
 error: missing documentation for macro
   --> $DIR/deny-missing-docs-macro.rs:6:1
    |
-LL | macro_rules! foo { //~ ERROR
+LL | macro_rules! foo {
    | ^^^^^^^^^^^^^^^^
    |
 note: lint level defined here

src/test/rustdoc-ui/intra-doc-alias-ice.stderr

@@ -1,7 +1,7 @@
 error: `[TypeAlias::hoge]` cannot be resolved, ignoring it...
   --> $DIR/intra-doc-alias-ice.rs:5:30
    |
-LL | /// [broken cross-reference](TypeAlias::hoge) //~ ERROR
+LL | /// [broken cross-reference](TypeAlias::hoge)
    |                              ^^^^^^^^^^^^^^^ cannot be resolved, ignoring
    |
 note: lint level defined here

src/test/ui-fulldeps/dropck_tarena_cycle_checked.stderr

@@ -3,7 +3,7 @@ error[E0597]: `arena` does not live long enough
    |
 LL |     f(&arena);
    |        ^^^^^ borrowed value does not live long enough
-LL | } //~^ ERROR `arena` does not live long enough
+LL | }
    | - `arena` dropped here while still borrowed
    |
    = note: values in a scope are dropped in the opposite order they are created

src/test/ui-fulldeps/dropck_tarena_unsound_drop.stderr

@@ -3,7 +3,7 @@ error[E0597]: `arena` does not live long enough
    |
 LL |     f(&arena);
    |        ^^^^^ borrowed value does not live long enough
-LL | } //~^ ERROR `arena` does not live long enough
+LL | }
    | - `arena` dropped here while still borrowed
    |
    = note: values in a scope are dropped in the opposite order they are created

src/test/ui-fulldeps/issue-15778-fail.stderr

@@ -1,7 +1,7 @@
 error: crate is not marked with #![crate_okay]
   --> $DIR/issue-15778-fail.rs:5:1
    |
-LL | / #![feature(plugin)] //~ ERROR crate is not marked with #![crate_okay]
+LL | / #![feature(plugin)]
 LL | | #![plugin(lint_for_crate)]
 LL | |
 LL | | pub fn main() { }

src/test/ui-fulldeps/lint-group-plugin-deny-cmdline.stderr

@@ -1,15 +1,15 @@
 error: item is named 'lintme'
   --> $DIR/lint-group-plugin-deny-cmdline.rs:8:1
    |
-LL | fn lintme() { } //~ ERROR item is named 'lintme'
+LL | fn lintme() { }
    | ^^^^^^^^^^^^^^^
    |
    = note: `-D test-lint` implied by `-D lint-me`
 
 error: item is named 'pleaselintme'
   --> $DIR/lint-group-plugin-deny-cmdline.rs:10:1
    |
-LL | fn pleaselintme() { } //~ ERROR item is named 'pleaselintme'
+LL | fn pleaselintme() { }
    | ^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D please-lint` implied by `-D lint-me`

src/test/ui-fulldeps/lint-group-plugin.stderr

@@ -1,15 +1,15 @@
 warning: item is named 'lintme'
   --> $DIR/lint-group-plugin.rs:9:1
    |
-LL | fn lintme() { } //~ WARNING item is named 'lintme'
+LL | fn lintme() { }
    | ^^^^^^^^^^^^^^^
    |
    = note: #[warn(test_lint)] on by default
 
 warning: item is named 'pleaselintme'
   --> $DIR/lint-group-plugin.rs:10:1
    |
-LL | fn pleaselintme() { } //~ WARNING item is named 'pleaselintme'
+LL | fn pleaselintme() { }
    | ^^^^^^^^^^^^^^^^^^^^^
    |
    = note: #[warn(please_lint)] on by default

src/test/ui-fulldeps/lint-plugin-cmdline-load.stderr

@@ -1,7 +1,7 @@
 warning: item is named 'lintme'
   --> $DIR/lint-plugin-cmdline-load.rs:8:1
    |
-LL | fn lintme() { } //~ WARNING item is named 'lintme'
+LL | fn lintme() { }
    | ^^^^^^^^^^^^^^^
    |
    = note: #[warn(test_lint)] on by default