13 files changed, 101 insertions, 61 deletions
diff --git a/tests/ui/codegen/output-slot-init-vs-noninit.rs b/tests/ui/codegen/output-slot-init-vs-noninit.rs
index 97757e74fc4..55586843740 100644
--- a/tests/ui/codegen/output-slot-init-vs-noninit.rs
+++ b/tests/ui/codegen/output-slot-init-vs-noninit.rs
@@ -1,26 +1,48 @@
+//! Check that output slots work correctly for both initializing and non-initializing assignments.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/24>.
+
 //@ run-pass
 
 #![allow(dead_code)]
 #![allow(unused_assignments)]
 #![allow(unknown_lints)]
-
 #![allow(dead_assignment)]
 #![allow(unused_variables)]
 
-struct A { a: isize, b: isize }
-struct Abox { a: Box<isize>, b: Box<isize> }
+struct A {
+    a: isize,
+    b: isize,
+}
 
-fn ret_int_i() -> isize { 10 }
+struct Abox {
+    a: Box<isize>,
+    b: Box<isize>,
+}
 
-fn ret_ext_i() -> Box<isize> { Box::new(10) }
+fn ret_int_i() -> isize {
+    10
+}
 
-fn ret_int_rec() -> A { A {a: 10, b: 10} }
+fn ret_ext_i() -> Box<isize> {
+    Box::new(10)
+}
 
-fn ret_ext_rec() -> Box<A> { Box::new(A {a: 10, b: 10}) }
+fn ret_int_rec() -> A {
+    A { a: 10, b: 10 }
+}
 
-fn ret_ext_mem() -> Abox { Abox {a: Box::new(10), b: Box::new(10) } }
+fn ret_ext_rec() -> Box<A> {
+    Box::new(A { a: 10, b: 10 })
+}
+
+fn ret_ext_mem() -> Abox {
+    Abox { a: Box::new(10), b: Box::new(10) }
+}
 
-fn ret_ext_ext_mem() -> Box<Abox> { Box::new(Abox{a: Box::new(10), b: Box::new(10) }) }
+fn ret_ext_ext_mem() -> Box<Abox> {
+    Box::new(Abox { a: Box::new(10), b: Box::new(10) })
+}
 
 pub fn main() {
     let mut int_i: isize;
@@ -29,40 +51,28 @@ pub fn main() {
     let mut ext_rec: Box<A>;
     let mut ext_mem: Abox;
     let mut ext_ext_mem: Box<Abox>;
-    int_i = ret_int_i(); // initializing
 
+    int_i = ret_int_i(); // initializing
     int_i = ret_int_i(); // non-initializing
-
     int_i = ret_int_i(); // non-initializing
 
     ext_i = ret_ext_i(); // initializing
-
     ext_i = ret_ext_i(); // non-initializing
-
     ext_i = ret_ext_i(); // non-initializing
 
     int_rec = ret_int_rec(); // initializing
-
     int_rec = ret_int_rec(); // non-initializing
-
     int_rec = ret_int_rec(); // non-initializing
 
     ext_rec = ret_ext_rec(); // initializing
-
     ext_rec = ret_ext_rec(); // non-initializing
-
     ext_rec = ret_ext_rec(); // non-initializing
 
     ext_mem = ret_ext_mem(); // initializing
-
     ext_mem = ret_ext_mem(); // non-initializing
-
     ext_mem = ret_ext_mem(); // non-initializing
 
     ext_ext_mem = ret_ext_ext_mem(); // initializing
-
     ext_ext_mem = ret_ext_ext_mem(); // non-initializing
-
     ext_ext_mem = ret_ext_ext_mem(); // non-initializing
-
 }
diff --git a/tests/ui/codegen/remark-flag-functionality.rs b/tests/ui/codegen/remark-flag-functionality.rs
index 165fc63c007..797c55ba830 100644
--- a/tests/ui/codegen/remark-flag-functionality.rs
+++ b/tests/ui/codegen/remark-flag-functionality.rs
@@ -1,24 +1,26 @@
+//! Check that `-Cremark` flag correctly emits LLVM optimization remarks.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/90924>.
+
 //@ build-pass
 //@ ignore-pass
 //@ revisions: all inline merge1 merge2
 //@ compile-flags: --crate-type=lib -Cdebuginfo=1 -Copt-level=2
-//
+
 // Check that remarks can be enabled individually or with "all":
-//
 //@ [all]    compile-flags: -Cremark=all
 //@ [inline] compile-flags: -Cremark=inline
-//
+
 // Check that values of -Cremark flag are accumulated:
-//
 //@ [merge1] compile-flags: -Cremark=all    -Cremark=giraffe
 //@ [merge2] compile-flags: -Cremark=inline -Cremark=giraffe
+
 //@ dont-check-compiler-stderr
 //@ dont-require-annotations: NOTE
 
 #[no_mangle]
 #[inline(never)]
-pub fn f() {
-}
+pub fn f() {}
 
 #[no_mangle]
 pub fn g() {
diff --git a/tests/ui/codegen/shift-right-operand-mutation.rs b/tests/ui/codegen/shift-right-operand-mutation.rs
index 016a667e937..b37a0baa6f8 100644
--- a/tests/ui/codegen/shift-right-operand-mutation.rs
+++ b/tests/ui/codegen/shift-right-operand-mutation.rs
@@ -1,12 +1,19 @@
+//! Ensure shift operations don't mutate their right operand.
+//!
+//! This test checks that expressions like `0 << b` don't accidentally
+//! modify the variable `b` due to codegen issues with virtual registers.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/152>.
+
 //@ run-pass
 
-#![allow(unused_must_use)]
-// Regression test for issue #152.
 pub fn main() {
-    let mut b: usize = 1_usize;
-    while b < std::mem::size_of::<usize>() {
-        0_usize << b;
-        b <<= 1_usize;
-        println!("{}", b);
+    let mut b: usize = 1;
+    while b < size_of::<usize>() {
+        // This shift operation should not mutate `b`
+        let _ = 0_usize << b;
+        b <<= 1;
+        std::hint::black_box(b);
     }
+    assert_eq!(size_of::<usize>(), b);
 }
diff --git a/tests/ui/codegen/sret-aliasing-rules.rs b/tests/ui/codegen/sret-aliasing-rules.rs
index 0dfaa19fadb..f35e722f764 100644
--- a/tests/ui/codegen/sret-aliasing-rules.rs
+++ b/tests/ui/codegen/sret-aliasing-rules.rs
@@ -1,3 +1,11 @@
+//! Check that functions with sret results don't violate aliasing rules.
+//!
+//! When `foo = func(&mut foo)` is called, the compiler must avoid creating
+//! two mutable references to the same variable simultaneously (one for the
+//! parameter and one for the hidden sret out-pointer).
+//!
+//! Regression test for <https://github.com/rust-lang/rust/pull/18250>.
+
 //@ run-pass
 
 #[derive(Copy, Clone)]
@@ -14,10 +22,7 @@ pub fn foo(f: &mut Foo) -> Foo {
 }
 
 pub fn main() {
-    let mut f = Foo {
-        f1: 8,
-        _f2: 9,
-    };
+    let mut f = Foo { f1: 8, _f2: 9 };
     f = foo(&mut f);
     assert_eq!(f.f1, 8);
 }
diff --git a/tests/ui/macros/macro-paren-span-diagnostic.rs b/tests/ui/macros/macro-paren-span-diagnostic.rs
index c8cb63d5190..cbcb0231e4e 100644
--- a/tests/ui/macros/macro-paren-span-diagnostic.rs
+++ b/tests/ui/macros/macro-paren-span-diagnostic.rs
@@ -1,5 +1,6 @@
-// Be smart about span of parenthesized expression in macro.
+//! Check that error spans in parenthesized macro expressions point to the call site.
 
+#[rustfmt::skip]
 macro_rules! paren {
     ($e:expr) => (($e))
     //            ^^^^ do not highlight here
@@ -7,8 +8,9 @@ macro_rules! paren {
 
 mod m {
     pub struct S {
-        x: i32
+        x: i32,
     }
+
     pub fn make() -> S {
         S { x: 0 }
     }
diff --git a/tests/ui/macros/macro-paren-span-diagnostic.stderr b/tests/ui/macros/macro-paren-span-diagnostic.stderr
index da2f57033a4..ede6ff51c71 100644
--- a/tests/ui/macros/macro-paren-span-diagnostic.stderr
+++ b/tests/ui/macros/macro-paren-span-diagnostic.stderr
@@ -1,5 +1,5 @@
 error[E0616]: field `x` of struct `S` is private
-  --> $DIR/paren-span.rs:19:14
+  --> $DIR/macro-paren-span-diagnostic.rs:21:14
    |
 LL |     paren!(s.x);
    |              ^ private field
diff --git a/tests/ui/panics/panic-during-display-formatting.rs b/tests/ui/panics/panic-during-display-formatting.rs
index 6505a69fef7..a307ee49385 100644
--- a/tests/ui/panics/panic-during-display-formatting.rs
+++ b/tests/ui/panics/panic-during-display-formatting.rs
@@ -1,3 +1,5 @@
+//! Check that panics in `Display::fmt` during printing are properly handled.
+
 //@ run-pass
 //@ needs-unwind
 
@@ -18,8 +20,10 @@ impl Display for A {
 
 fn main() {
     set_output_capture(Some(Arc::new(Mutex::new(Vec::new()))));
-    assert!(std::panic::catch_unwind(|| {
-        eprintln!("{}", A);
-    })
-    .is_err());
+    assert!(
+        std::panic::catch_unwind(|| {
+            eprintln!("{}", A);
+        })
+        .is_err()
+    );
 }
diff --git a/tests/ui/panics/panic-handler-closures.rs b/tests/ui/panics/panic-handler-closures.rs
index b161859bf9c..27fea925720 100644
--- a/tests/ui/panics/panic-handler-closures.rs
+++ b/tests/ui/panics/panic-handler-closures.rs
@@ -1,10 +1,12 @@
-//@ build-pass (FIXME(62277): could be check-pass?)
+//! Check that closures can be used inside `#[panic_handler]` functions.
+
+//@ check-pass
 
 #![crate_type = "rlib"]
 #![no_std]
 
 #[panic_handler]
-pub fn panic_fmt(_: &::core::panic::PanicInfo) -> ! {
+pub fn panicfmt(_: &::core::panic::PanicInfo) -> ! {
     |x: u8| x;
     loop {}
 }
diff --git a/tests/ui/parser/ufcs-return-unused-parens.fixed b/tests/ui/parser/ufcs-return-unused-parens.fixed
index 440b22edd7d..811a853b769 100644
--- a/tests/ui/parser/ufcs-return-unused-parens.fixed
+++ b/tests/ui/parser/ufcs-return-unused-parens.fixed
@@ -1,13 +1,16 @@
+//! Check that UFCS syntax works correctly in return statements
+//! without requiring workaround parentheses.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/37765>.
+
 //@ run-pass
 //@ run-rustfix
 
 #![allow(dead_code)]
 #![warn(unused_parens)]
 
-// Parser test for #37765
-
 fn with_parens<T: ToString>(arg: T) -> String {
-    return <T as ToString>::to_string(&arg); //~WARN unnecessary parentheses around `return` value
+    return <T as ToString>::to_string(&arg); //~ WARN unnecessary parentheses around `return` value
 }
 
 fn no_parens<T: ToString>(arg: T) -> String {
diff --git a/tests/ui/parser/ufcs-return-unused-parens.rs b/tests/ui/parser/ufcs-return-unused-parens.rs
index 7eaacd6bba7..6ea69ef9a26 100644
--- a/tests/ui/parser/ufcs-return-unused-parens.rs
+++ b/tests/ui/parser/ufcs-return-unused-parens.rs
@@ -1,13 +1,16 @@
+//! Check that UFCS syntax works correctly in return statements
+//! without requiring workaround parentheses.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/37765>.
+
 //@ run-pass
 //@ run-rustfix
 
 #![allow(dead_code)]
 #![warn(unused_parens)]
 
-// Parser test for #37765
-
 fn with_parens<T: ToString>(arg: T) -> String {
-    return (<T as ToString>::to_string(&arg)); //~WARN unnecessary parentheses around `return` value
+    return (<T as ToString>::to_string(&arg)); //~ WARN unnecessary parentheses around `return` value
 }
 
 fn no_parens<T: ToString>(arg: T) -> String {
diff --git a/tests/ui/parser/ufcs-return-unused-parens.stderr b/tests/ui/parser/ufcs-return-unused-parens.stderr
index 2cc786fd947..6c09e98e7b1 100644
--- a/tests/ui/parser/ufcs-return-unused-parens.stderr
+++ b/tests/ui/parser/ufcs-return-unused-parens.stderr
@@ -1,11 +1,11 @@
 warning: unnecessary parentheses around `return` value
-  --> $DIR/path-lookahead.rs:10:12
+  --> $DIR/ufcs-return-unused-parens.rs:13:12
    |
 LL |     return (<T as ToString>::to_string(&arg));
    |            ^                                ^
    |
 note: the lint level is defined here
-  --> $DIR/path-lookahead.rs:5:9
+  --> $DIR/ufcs-return-unused-parens.rs:10:9
    |
 LL | #![warn(unused_parens)]
    |         ^^^^^^^^^^^^^
diff --git a/tests/ui/traits/partialeq-ref-mismatch-diagnostic.rs b/tests/ui/traits/partialeq-ref-mismatch-diagnostic.rs
index 34b88b8a866..26ef8050b87 100644
--- a/tests/ui/traits/partialeq-ref-mismatch-diagnostic.rs
+++ b/tests/ui/traits/partialeq-ref-mismatch-diagnostic.rs
@@ -1,8 +1,10 @@
+//! Check diagnostic messages for `PartialEq` trait bound mismatches between `&T` and `T`.
+
 fn foo<T: PartialEq>(a: &T, b: T) {
     a == b; //~ ERROR E0277
 }
 
-fn foo2<T: PartialEq>(a: &T, b: T) where {
+fn foo2<T: PartialEq>(a: &T, b: T) {
     a == b; //~ ERROR E0277
 }
 
diff --git a/tests/ui/traits/partialeq-ref-mismatch-diagnostic.stderr b/tests/ui/traits/partialeq-ref-mismatch-diagnostic.stderr
index f5de1308e87..4cbd31656dc 100644
--- a/tests/ui/traits/partialeq-ref-mismatch-diagnostic.stderr
+++ b/tests/ui/traits/partialeq-ref-mismatch-diagnostic.stderr
@@ -1,5 +1,5 @@
 error[E0277]: can't compare `&T` with `T`
-  --> $DIR/partialeq_help.rs:2:7
+  --> $DIR/partialeq-ref-mismatch-diagnostic.rs:4:7
    |
 LL |     a == b;
    |       ^^ no implementation for `&T == T`
@@ -15,7 +15,7 @@ LL | fn foo<T: PartialEq>(a: &T, b: T) where &T: PartialEq<T> {
    |                                   ++++++++++++++++++++++
 
 error[E0277]: can't compare `&T` with `T`
-  --> $DIR/partialeq_help.rs:6:7
+  --> $DIR/partialeq-ref-mismatch-diagnostic.rs:8:7
    |
 LL |     a == b;
    |       ^^ no implementation for `&T == T`
@@ -25,10 +25,10 @@ help: consider dereferencing here
    |
 LL |     *a == b;
    |     +
-help: consider extending the `where` clause, but there might be an alternative better way to express this requirement
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
 LL | fn foo2<T: PartialEq>(a: &T, b: T) where &T: PartialEq<T> {
-   |                                          ++++++++++++++++
+   |                                    ++++++++++++++++++++++
 
 error: aborting due to 2 previous errors