Auto merge of #149729 - matthiaskrgr:rollup-25plwn0, r=matthiaskrgr

Rollup of 4 pull requests

Successful merges:

 - rust-lang/rust#147136 (Add warn-by-default lint for visibility on `const _` declarations)
 - rust-lang/rust#149498 (Tidying up `tests/ui/issues` tests [1/N])
 - rust-lang/rust#149721 (rustc book: fix `*-pc-windows-msvc` link label in sidebar)
 - rust-lang/rust#149724 (Fix off-by-one staging output when testing the library)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -33,7 +33,7 @@ use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
     DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, MISSING_UNSAFE_ON_EXTERN,
-    PATTERNS_IN_FNS_WITHOUT_BODY,
+    PATTERNS_IN_FNS_WITHOUT_BODY, UNUSED_VISIBILITIES,
 };
 use rustc_session::parse::feature_err;
 use rustc_span::{Ident, Span, kw, sym};
@@ -1339,7 +1339,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     }
                 });
             }
-            ItemKind::Const(box ConstItem { defaultness, rhs, .. }) => {
+            ItemKind::Const(box ConstItem { defaultness, ident, rhs, .. }) => {
                 self.check_defaultness(item.span, *defaultness);
                 if rhs.is_none() {
                     self.dcx().emit_err(errors::ConstWithoutBody {
@@ -1347,6 +1347,18 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         replace_span: self.ending_semi_or_hi(item.span),
                     });
                 }
+                if ident.name == kw::Underscore
+                    && !matches!(item.vis.kind, VisibilityKind::Inherited)
+                    && ident.span.eq_ctxt(item.vis.span)
+                {
+                    self.lint_buffer.buffer_lint(
+                        UNUSED_VISIBILITIES,
+                        item.id,
+                        item.vis.span,
+                        BuiltinLintDiag::UnusedVisibility(item.vis.span),
+                    )
+                }
+
                 visit::walk_item(self, item);
             }
             ItemKind::Static(box StaticItem { expr, safety, .. }) => {

compiler/rustc_lint/messages.ftl

@@ -978,6 +978,10 @@ lint_unused_op = unused {$op} that must be used
 
 lint_unused_result = unused result of type `{$ty}`
 
+lint_unused_visibilities = visibility qualifiers have no effect on `const _` declarations
+    .note = `const _` does not declare a name, so there is nothing for the qualifier to apply to
+    .suggestion = remove the qualifier
+
 lint_use_let_underscore_ignore_suggestion = use `let _ = ...` to ignore the expression or result
 
 lint_useless_ptr_null_checks_fn_ptr = function pointers are not nullable, so checking them for null will always return false

compiler/rustc_lint/src/early/diagnostics.rs

@@ -302,6 +302,9 @@ pub fn decorate_builtin_lint(
         BuiltinLintDiag::UnusedCrateDependency { extern_crate, local_crate } => {
             lints::UnusedCrateDependency { extern_crate, local_crate }.decorate_lint(diag)
         }
+        BuiltinLintDiag::UnusedVisibility(span) => {
+            lints::UnusedVisibility { span }.decorate_lint(diag)
+        }
         BuiltinLintDiag::AttributeLint(kind) => decorate_attribute_lint(sess, tcx, &kind, diag),
     }
 }

compiler/rustc_lint/src/lib.rs

@@ -291,6 +291,7 @@ fn register_builtins(store: &mut LintStore) {
         "unused",
         UNUSED_IMPORTS,
         UNUSED_VARIABLES,
+        UNUSED_VISIBILITIES,
         UNUSED_ASSIGNMENTS,
         DEAD_CODE,
         UNUSED_MUT,

compiler/rustc_lint/src/lints.rs

@@ -3191,3 +3191,11 @@ pub(crate) struct UnsafeAttrOutsideUnsafeSuggestion {
     #[suggestion_part(code = ")")]
     pub right: Span,
 }
+
+#[derive(LintDiagnostic)]
+#[diag(lint_unused_visibilities)]
+#[note]
+pub(crate) struct UnusedVisibility {
+    #[suggestion(style = "short", code = "", applicability = "machine-applicable")]
+    pub span: Span,
+}

compiler/rustc_lint_defs/src/builtin.rs

@@ -143,6 +143,7 @@ declare_lint_pass! {
         UNUSED_QUALIFICATIONS,
         UNUSED_UNSAFE,
         UNUSED_VARIABLES,
+        UNUSED_VISIBILITIES,
         USELESS_DEPRECATED,
         VARARGS_WITHOUT_PATTERN,
         WARNINGS,
@@ -693,6 +694,26 @@ declare_lint! {
     "detect variables which are not used in any way"
 }
 
+declare_lint! {
+    /// The `unused_visibilities` lint detects visibility qualifiers (like `pub`)
+    /// on a `const _` item.
+    ///
+    /// ### Example
+    ///
+    /// ```rust
+    /// pub const _: () = {};
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// These qualifiers have no effect, as `const _` items are unnameable.
+    pub UNUSED_VISIBILITIES,
+    Warn,
+    "detect visibility qualifiers on `const _` items"
+}
+
 declare_lint! {
     /// The `unused_assignments` lint detects assignments that will never be read.
     ///

compiler/rustc_lint_defs/src/lib.rs

@@ -696,6 +696,7 @@ pub enum BuiltinLintDiag {
         extern_crate: Symbol,
         local_crate: Symbol,
     },
+    UnusedVisibility(Span),
     AttributeLint(AttributeLintKind),
 }
 

src/bootstrap/src/core/build_steps/test.rs

@@ -2818,10 +2818,15 @@ fn run_cargo_test<'a>(
     builder: &Builder<'_>,
 ) -> bool {
     let compiler = cargo.compiler();
+    let stage = match cargo.mode() {
+        Mode::Std => compiler.stage,
+        _ => compiler.stage + 1,
+    };
+
     let mut cargo = prepare_cargo_test(cargo, libtest_args, crates, target, builder);
     let _time = helpers::timeit(builder);
-    let _group =
-        description.into().and_then(|what| builder.msg_test(what, target, compiler.stage + 1));
+
+    let _group = description.into().and_then(|what| builder.msg_test(what, target, stage));
 
     #[cfg(feature = "build-metrics")]
     builder.metrics.begin_test_suite(

src/bootstrap/src/core/builder/cargo.rs

@@ -98,6 +98,7 @@ pub struct Cargo {
     command: BootstrapCommand,
     args: Vec<OsString>,
     compiler: Compiler,
+    mode: Mode,
     target: TargetSelection,
     rustflags: Rustflags,
     rustdocflags: Rustflags,
@@ -141,6 +142,10 @@ impl Cargo {
         self.compiler
     }
 
+    pub fn mode(&self) -> Mode {
+        self.mode
+    }
+
     pub fn into_cmd(self) -> BootstrapCommand {
         self.into()
     }
@@ -1404,6 +1409,7 @@ impl Builder<'_> {
             command: cargo,
             args: vec![],
             compiler,
+            mode,
             target,
             rustflags,
             rustdocflags,

src/doc/rustc/src/SUMMARY.md

@@ -130,7 +130,7 @@
     - [\*-unknown-openbsd](platform-support/openbsd.md)
     - [\*-unknown-redox](platform-support/redox.md)
     - [\*-unknown-uefi](platform-support/unknown-uefi.md)
-    - [\*-unknown-windows-msvc](platform-support/windows-msvc.md)
+    - [\*-pc-windows-msvc](platform-support/windows-msvc.md)
     - [\*-uwp-windows-msvc](platform-support/uwp-windows-msvc.md)
     - [\*-wrs-vxworks](platform-support/vxworks.md)
     - [wasm32-wasip1](platform-support/wasm32-wasip1.md)

src/tools/clippy/tests/ui-toml/absolute_paths/absolute_paths.no_short.stderr

@@ -71,10 +71,10 @@ LL |         impl<T: core::cmp::Eq> core::fmt::Display for X<T>
    |                                ^^^^^^^^^^^^^^^^^^
 
 error: consider bringing this path into scope with the `use` keyword
-  --> tests/ui-toml/absolute_paths/absolute_paths.rs:113:14
+  --> tests/ui-toml/absolute_paths/absolute_paths.rs:113:10
    |
-LL | pub const _: crate::S = {
-   |              ^^^^^^^^
+LL | const _: crate::S = {
+   |          ^^^^^^^^
 
 error: consider bringing this path into scope with the `use` keyword
   --> tests/ui-toml/absolute_paths/absolute_paths.rs:114:9

src/tools/clippy/tests/ui-toml/absolute_paths/absolute_paths.rs

@@ -110,7 +110,7 @@ mod m1 {
 }
 
 //~[no_short]v absolute_paths
-pub const _: crate::S = {
+const _: crate::S = {
     let crate::S = m1::S; //~[no_short] absolute_paths
 
     crate::m1::S

tests/ui/box/self-assignment.rs

@@ -0,0 +1,10 @@
+//@ run-pass
+//! regression test for <https://github.com/rust-lang/rust/issues/3290>
+
+#![allow(dead_code)]
+
+pub fn main() {
+    let mut x: Box<_> = Box::new(3);
+    x = x;
+    assert_eq!(*x, 3);
+}

tests/ui/consts/promoted_const_call3.rs

@@ -4,12 +4,12 @@ pub const C: () = {
     //~^ ERROR: destructor of `String` cannot be evaluated at compile-time
 };
 
-pub const _: () = {
+const _: () = {
     let _: &'static _ = &id(&String::new());
     //~^ ERROR: destructor of `String` cannot be evaluated at compile-time
 };
 
-pub const _: () = {
+const _: () = {
     let _: &'static _ = &std::mem::ManuallyDrop::new(String::new());
     //~^ ERROR: temporary value dropped while borrowed
 };

tests/ui/consts/ptr_is_null.rs

@@ -5,12 +5,12 @@
 
 const FOO: &usize = &42;
 
-pub const _: () = assert!(!(FOO as *const usize).is_null());
+const _: () = assert!(!(FOO as *const usize).is_null());
 
-pub const _: () = assert!(!(42 as *const usize).is_null());
+const _: () = assert!(!(42 as *const usize).is_null());
 
-pub const _: () = assert!((0 as *const usize).is_null());
+const _: () = assert!((0 as *const usize).is_null());
 
-pub const _: () = assert!(std::ptr::null::<usize>().is_null());
+const _: () = assert!(std::ptr::null::<usize>().is_null());
 
-pub const _: () = assert!(!("foo" as *const str).is_null());
+const _: () = assert!(!("foo" as *const str).is_null());

tests/ui/empty/empty-struct-unit-expr.rs

@@ -1,4 +1,5 @@
 // Can't use unit struct as constructor function
+// related issue <https://github.com/rust-lang/rust/issues/20714>
 
 //@ aux-build:empty-struct.rs
 
@@ -8,7 +9,7 @@ use empty_struct::*;
 struct Empty2;
 
 enum E {
-    Empty4
+    Empty4,
 }
 
 fn main() {

tests/ui/empty/empty-struct-unit-expr.stderr

@@ -1,5 +1,5 @@
 error[E0618]: expected function, found struct `Empty2`
-  --> $DIR/empty-struct-unit-expr.rs:15:14
+  --> $DIR/empty-struct-unit-expr.rs:16:14
    |
 LL | struct Empty2;
    | ------------- struct `Empty2` defined here
@@ -16,9 +16,9 @@ LL +     let e2 = Empty2;
    |
 
 error[E0618]: expected function, found enum variant `E::Empty4`
-  --> $DIR/empty-struct-unit-expr.rs:16:14
+  --> $DIR/empty-struct-unit-expr.rs:17:14
    |
-LL |     Empty4
+LL |     Empty4,
    |     ------ enum variant `E::Empty4` defined here
 ...
 LL |     let e4 = E::Empty4();
@@ -33,7 +33,7 @@ LL +     let e4 = E::Empty4;
    |
 
 error[E0618]: expected function, found struct `XEmpty2`
-  --> $DIR/empty-struct-unit-expr.rs:18:15
+  --> $DIR/empty-struct-unit-expr.rs:19:15
    |
 LL |     let xe2 = XEmpty2();
    |               ^^^^^^^--
@@ -47,7 +47,7 @@ LL +     let xe2 = XEmpty2;
    |
 
 error[E0618]: expected function, found enum variant `XE::XEmpty4`
-  --> $DIR/empty-struct-unit-expr.rs:19:15
+  --> $DIR/empty-struct-unit-expr.rs:20:15
    |
 LL |     let xe4 = XE::XEmpty4();
    |               ^^^^^^^^^^^--

tests/ui/for-loop-while/break-continue-in-loop-while-condition.rs

@@ -1,3 +1,6 @@
+//! regression test for #37576, #50802
+//! Tests that using unlabeled `break` or `continue` within a loop or while's condition.
+
 fn main() {
     'test_1: while break 'test_1 {}
     while break {}
@@ -7,9 +10,13 @@ fn main() {
     while let true = break {}
     //~^ ERROR `break` or `continue` with no label
 
-    loop { 'test_3: while break 'test_3 {} }
-    loop { while break {} }
-    //~^ ERROR `break` or `continue` with no label
+    loop {
+        'test_3: while break 'test_3 {}
+    }
+    loop {
+        while break {}
+        //~^ ERROR `break` or `continue` with no label
+    }
 
     loop {
         'test_4: while break 'test_4 {}
@@ -29,9 +36,13 @@ fn main() {
     while let true = continue {}
     //~^ ERROR `break` or `continue` with no label
 
-    loop { 'test_7: while continue 'test_7 {} }
-    loop { while continue {} }
-    //~^ ERROR `break` or `continue` with no label
+    loop {
+        'test_7: while continue 'test_7 {}
+    }
+    loop {
+        while continue {}
+        //~^ ERROR `break` or `continue` with no label
+    }
 
     loop {
         'test_8: while continue 'test_8 {}
@@ -42,4 +53,13 @@ fn main() {
         //~^ ERROR `break` or `continue` with no label
         continue;
     }
+
+    'test_9: loop {
+        break while continue 'test_9 {};
+    }
+    loop {
+        break while continue {
+            //~^ ERROR `break` or `continue` with no label
+        };
+    }
 }

tests/ui/for-loop-while/break-continue-in-loop-while-condition.stderr

@@ -1,51 +1,57 @@
 error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:3:11
+  --> $DIR/break-continue-in-loop-while-condition.rs:6:11
    |
 LL |     while break {}
    |           ^^^^^ unlabeled `break` in the condition of a `while` loop
 
 error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:7:22
+  --> $DIR/break-continue-in-loop-while-condition.rs:10:22
    |
 LL |     while let true = break {}
    |                      ^^^^^ unlabeled `break` in the condition of a `while` loop
 
 error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:11:18
-   |
-LL |     loop { while break {} }
-   |                  ^^^^^ unlabeled `break` in the condition of a `while` loop
-
-error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:19:15
+  --> $DIR/break-continue-in-loop-while-condition.rs:17:15
    |
 LL |         while break {}
    |               ^^^^^ unlabeled `break` in the condition of a `while` loop
 
 error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:25:11
+  --> $DIR/break-continue-in-loop-while-condition.rs:26:15
+   |
+LL |         while break {}
+   |               ^^^^^ unlabeled `break` in the condition of a `while` loop
+
+error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
+  --> $DIR/break-continue-in-loop-while-condition.rs:32:11
    |
 LL |     while continue {}
    |           ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
 
 error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:29:22
+  --> $DIR/break-continue-in-loop-while-condition.rs:36:22
    |
 LL |     while let true = continue {}
    |                      ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
 
 error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:33:18
-   |
-LL |     loop { while continue {} }
-   |                  ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
-
-error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-37576.rs:41:15
+  --> $DIR/break-continue-in-loop-while-condition.rs:43:15
    |
 LL |         while continue {}
    |               ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
 
-error: aborting due to 8 previous errors
+error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
+  --> $DIR/break-continue-in-loop-while-condition.rs:52:15
+   |
+LL |         while continue {}
+   |               ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
+
+error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
+  --> $DIR/break-continue-in-loop-while-condition.rs:61:21
+   |
+LL |         break while continue {
+   |                     ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
+
+error: aborting due to 9 previous errors
 
 For more information about this error, try `rustc --explain E0590`.

tests/ui/issues/issue-20714.rs

@@ -1,5 +0,0 @@
-struct G;
-
-fn main() {
-    let g = G(); //~ ERROR: expected function, found struct `G`
-}

tests/ui/issues/issue-20714.stderr

@@ -1,20 +0,0 @@
-error[E0618]: expected function, found struct `G`
-  --> $DIR/issue-20714.rs:4:13
-   |
-LL | struct G;
-   | -------- struct `G` defined here
-...
-LL |     let g = G();
-   |             ^--
-   |             |
-   |             call expression requires function
-   |
-help: `G` is a unit struct, and does not take parentheses to be constructed
-   |
-LL -     let g = G();
-LL +     let g = G;
-   |
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0618`.

tests/ui/issues/issue-2383.rs

@@ -1,8 +0,0 @@
-//@ run-pass
-
-use std::collections::VecDeque;
-
-pub fn main() {
-    let mut q = VecDeque::new();
-    q.push_front(10);
-}

tests/ui/issues/issue-2951.rs

@@ -1,13 +0,0 @@
-//@ dont-require-annotations: NOTE
-
-fn foo<T, U>(x: T, y: U) {
-    let mut xx = x;
-    xx = y;
-    //~^  ERROR mismatched types
-    //~| NOTE expected type parameter `T`, found type parameter `U`
-    //~| NOTE expected type parameter `T`
-    //~| NOTE found type parameter `U`
-}
-
-fn main() {
-}

tests/ui/issues/issue-2951.stderr

@@ -1,20 +0,0 @@
-error[E0308]: mismatched types
-  --> $DIR/issue-2951.rs:5:10
-   |
-LL | fn foo<T, U>(x: T, y: U) {
-   |        -  - found type parameter
-   |        |
-   |        expected type parameter
-LL |     let mut xx = x;
-   |                  - expected due to this value
-LL |     xx = y;
-   |          ^ expected type parameter `T`, found type parameter `U`
-   |
-   = note: expected type parameter `T`
-              found type parameter `U`
-   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
-   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0308`.

tests/ui/issues/issue-3290.rs

@@ -1,8 +0,0 @@
-//@ run-pass
-#![allow(dead_code)]
-
-pub fn main() {
-   let mut x: Box<_> = Box::new(3);
-   x = x;
-   assert_eq!(*x, 3);
-}

tests/ui/issues/issue-50802.rs

@@ -1,8 +0,0 @@
-#[allow(unreachable_code)]
-
-fn main() {
-    loop {
-        break while continue { //~ ERROR E0590
-        }
-    }
-}

tests/ui/issues/issue-50802.stderr

@@ -1,9 +0,0 @@
-error[E0590]: `break` or `continue` with no label in the condition of a `while` loop
-  --> $DIR/issue-50802.rs:5:21
-   |
-LL |         break while continue {
-   |                     ^^^^^^^^ unlabeled `continue` in the condition of a `while` loop
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0590`.

tests/ui/lint/issue-70819-dont-override-forbid-in-same-scope.stderr

@@ -413,3 +413,21 @@ note: the lint level is defined here
 LL | #![forbid(forbidden_lint_groups)]
    |           ^^^^^^^^^^^^^^^^^^^^^
 
+Future breakage diagnostic:
+error: warn(unused) incompatible with previous forbid
+  --> $DIR/issue-70819-dont-override-forbid-in-same-scope.rs:22:13
+   |
+LL |     #![forbid(unused)]
+   |               ------ `forbid` level set here
+LL |     #![deny(unused)]
+LL |     #![warn(unused)]
+   |             ^^^^^^ overruled by previous forbid
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #81670 <https://github.com/rust-lang/rust/issues/81670>
+note: the lint level is defined here
+  --> $DIR/issue-70819-dont-override-forbid-in-same-scope.rs:17:11
+   |
+LL | #![forbid(forbidden_lint_groups)]
+   |           ^^^^^^^^^^^^^^^^^^^^^
+

tests/ui/lint/outer-forbid.stderr

@@ -453,3 +453,21 @@ note: the lint level is defined here
 LL | #![forbid(forbidden_lint_groups)]
    |           ^^^^^^^^^^^^^^^^^^^^^
 
+Future breakage diagnostic:
+error: allow(unused) incompatible with previous forbid
+  --> $DIR/outer-forbid.rs:25:9
+   |
+LL | #![forbid(unused, non_snake_case)]
+   |           ------ `forbid` level set here
+...
+LL | #[allow(unused)]
+   |         ^^^^^^ overruled by previous forbid
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #81670 <https://github.com/rust-lang/rust/issues/81670>
+note: the lint level is defined here
+  --> $DIR/outer-forbid.rs:18:11
+   |
+LL | #![forbid(forbidden_lint_groups)]
+   |           ^^^^^^^^^^^^^^^^^^^^^
+

tests/ui/lint/unused-visibilities.fixed

@@ -0,0 +1,29 @@
+//@ check-pass
+//@ run-rustfix
+
+#![warn(unused_visibilities)]
+
+ const _: () = {};
+//~^WARN visibility qualifiers have no effect on `const _` declarations
+
+ const _: () = {};
+//~^WARN visibility qualifiers have no effect on `const _` declarations
+
+macro_rules! foo {
+    () => {
+         const _: () = {};
+        //~^WARN visibility qualifiers have no effect on `const _` declarations
+    };
+}
+
+foo!();
+
+macro_rules! bar {
+    ($tt:tt) => {
+        pub const $tt: () = {};
+    };
+}
+
+bar!(_);
+
+fn main() {}

tests/ui/lint/unused-visibilities.rs

@@ -0,0 +1,29 @@
+//@ check-pass
+//@ run-rustfix
+
+#![warn(unused_visibilities)]
+
+pub const _: () = {};
+//~^WARN visibility qualifiers have no effect on `const _` declarations
+
+pub(self) const _: () = {};
+//~^WARN visibility qualifiers have no effect on `const _` declarations
+
+macro_rules! foo {
+    () => {
+        pub const _: () = {};
+        //~^WARN visibility qualifiers have no effect on `const _` declarations
+    };
+}
+
+foo!();
+
+macro_rules! bar {
+    ($tt:tt) => {
+        pub const $tt: () = {};
+    };
+}
+
+bar!(_);
+
+fn main() {}

tests/ui/lint/unused-visibilities.stderr

@@ -0,0 +1,35 @@
+warning: visibility qualifiers have no effect on `const _` declarations
+  --> $DIR/unused-visibilities.rs:6:1
+   |
+LL | pub const _: () = {};
+   | ^^^ help: remove the qualifier
+   |
+   = note: `const _` does not declare a name, so there is nothing for the qualifier to apply to
+note: the lint level is defined here
+  --> $DIR/unused-visibilities.rs:4:9
+   |
+LL | #![warn(unused_visibilities)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+warning: visibility qualifiers have no effect on `const _` declarations
+  --> $DIR/unused-visibilities.rs:9:1
+   |
+LL | pub(self) const _: () = {};
+   | ^^^^^^^^^ help: remove the qualifier
+   |
+   = note: `const _` does not declare a name, so there is nothing for the qualifier to apply to
+
+warning: visibility qualifiers have no effect on `const _` declarations
+  --> $DIR/unused-visibilities.rs:14:9
+   |
+LL |         pub const _: () = {};
+   |         ^^^ help: remove the qualifier
+...
+LL | foo!();
+   | ------ in this macro invocation
+   |
+   = note: `const _` does not declare a name, so there is nothing for the qualifier to apply to
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: 3 warnings emitted
+

tests/ui/match/match-option-result-mismatch.rs

@@ -1,6 +1,9 @@
+//! regression test for <https://github.com/rust-lang/rust/issues/3680>
+
 fn main() {
-    match None { //~ NOTE this expression has type `Option<_>`
-        Err(_) => ()
+    match None {
+        //~^ NOTE this expression has type `Option<_>`
+        Err(_) => (),
         //~^ ERROR mismatched types
         //~| NOTE expected enum `Option<_>`
         //~| NOTE found enum `Result<_, _>`

tests/ui/match/match-option-result-mismatch.stderr

@@ -1,16 +1,17 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-3680.rs:3:9
+  --> $DIR/match-option-result-mismatch.rs:6:9
    |
 LL |     match None {
    |           ---- this expression has type `Option<_>`
-LL |         Err(_) => ()
+LL |
+LL |         Err(_) => (),
    |         ^^^^^^ expected `Option<_>`, found `Result<_, _>`
    |
    = note: expected enum `Option<_>`
               found enum `Result<_, _>`
 help: try wrapping the pattern in `Some`
    |
-LL |         Some(Err(_)) => ()
+LL |         Some(Err(_)) => (),
    |         +++++      +
 
 error: aborting due to 1 previous error

tests/ui/numeric/ref-int.rs

@@ -1,4 +1,5 @@
 //@ run-pass
+//! regression test for <https://github.com/rust-lang/rust/issues/3091>
 
 pub fn main() {
     let x = 1;

tests/ui/traits/const-traits/call.rs

@@ -3,7 +3,7 @@
 #![feature(const_closures, const_trait_impl)]
 #![allow(incomplete_features)]
 
-pub const _: () = {
+const _: () = {
     assert!((const || true)());
     //~^ ERROR }: [const] Fn()` is not satisfied
 };

tests/ui/type/type-parameter-names.rs

@@ -1,14 +1,24 @@
 // Test that we print out the names of type parameters correctly in
 // our error messages.
+// related issue <https://github.com/rust-lang/rust/issues/2951>
 
 //@ dont-require-annotations: NOTE
 
 fn foo<Foo, Bar>(x: Foo) -> Bar {
     x
-//~^ ERROR mismatched types
-//~| NOTE expected type parameter `Bar`, found type parameter `Foo`
-//~| NOTE expected type parameter `Bar`
-//~| NOTE found type parameter `Foo`
+    //~^ ERROR mismatched types
+    //~| NOTE expected type parameter `Bar`, found type parameter `Foo`
+    //~| NOTE expected type parameter `Bar`
+    //~| NOTE found type parameter `Foo`
+}
+
+fn bar<Foo, Bar>(x: Foo, y: Bar) {
+    let mut xx = x;
+    xx = y;
+    //~^ ERROR mismatched types
+    //~| NOTE expected type parameter `Foo`, found type parameter `Bar`
+    //~| NOTE expected type parameter `Foo`
+    //~| NOTE found type parameter `Bar`
 }
 
 fn main() {}

tests/ui/type/type-parameter-names.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/type-parameter-names.rs:7:5
+  --> $DIR/type-parameter-names.rs:8:5
    |
 LL | fn foo<Foo, Bar>(x: Foo) -> Bar {
    |        ---  ---             --- expected `Bar` because of return type
@@ -15,6 +15,23 @@ LL |     x
    = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
    = note: the caller chooses a type for `Bar` which can be different from `Foo`
 
-error: aborting due to 1 previous error
+error[E0308]: mismatched types
+  --> $DIR/type-parameter-names.rs:17:10
+   |
+LL | fn bar<Foo, Bar>(x: Foo, y: Bar) {
+   |        ---  --- found type parameter
+   |        |
+   |        expected type parameter
+LL |     let mut xx = x;
+   |                  - expected due to this value
+LL |     xx = y;
+   |          ^ expected type parameter `Foo`, found type parameter `Bar`
+   |
+   = note: expected type parameter `Foo`
+              found type parameter `Bar`
+   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
+   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0308`.