cleaned up some tests

Author: Kivooeo

tests/ui/allocator/weak-uninhabited-type.rs

@@ -1,7 +1,13 @@
+//! Checks that `Weak` pointers can be created with an empty enum type parameter.
+//! And generic `Weak` handles zero-variant enums without error.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/48493>
+
 //@ run-pass
 
+enum Void {}
+
 fn main() {
-    enum Void {}
     let _ = std::rc::Weak::<Void>::new();
     let _ = std::sync::Weak::<Void>::new();
 }

tests/ui/binding/underscore-prefixed-function-argument.rs

@@ -1,11 +1,13 @@
-//@ run-pass
+//! Test that argument names starting with `_` are usable.
 
-fn good(_a: &isize) {
-}
+//@ run-pass
 
-// unnamed argument &isize is now parse x: &isize
+fn good(_a: &isize) {}
 
-fn called<F>(_f: F) where F: FnOnce(&isize) {
+fn called<F>(_f: F)
+where
+    F: FnOnce(&isize),
+{
 }
 
 pub fn main() {

tests/ui/borrowck/ownership-struct-update-moved-error.rs

@@ -1,17 +1,19 @@
-struct Mine{
+//! Checks borrow after move error when using `self` consuming method with struct update syntax.
+
+struct Mine {
     test: String,
-    other_val: isize
+    other_val: isize,
 }
 
-impl Mine{
-    fn make_string_bar(mut self) -> Mine{
+impl Mine {
+    fn make_string_bar(mut self) -> Mine {
         self.test = "Bar".to_string();
         self
     }
 }
 
-fn main(){
-    let start = Mine{test:"Foo".to_string(), other_val:0};
-    let end = Mine{other_val:1, ..start.make_string_bar()};
+fn main() {
+    let start = Mine { test: "Foo".to_string(), other_val: 0 };
+    let end = Mine { other_val: 1, ..start.make_string_bar() };
     println!("{}", start.test); //~ ERROR borrow of moved value: `start`
 }

tests/ui/borrowck/ownership-struct-update-moved-error.stderr

@@ -1,17 +1,17 @@
 error[E0382]: borrow of moved value: `start`
-  --> $DIR/walk-struct-literal-with.rs:16:20
+  --> $DIR/ownership-struct-update-moved-error.rs:18:20
    |
-LL |     let start = Mine{test:"Foo".to_string(), other_val:0};
+LL |     let start = Mine { test: "Foo".to_string(), other_val: 0 };
    |         ----- move occurs because `start` has type `Mine`, which does not implement the `Copy` trait
-LL |     let end = Mine{other_val:1, ..start.make_string_bar()};
-   |                                         ----------------- `start` moved due to this method call
+LL |     let end = Mine { other_val: 1, ..start.make_string_bar() };
+   |                                            ----------------- `start` moved due to this method call
 LL |     println!("{}", start.test);
    |                    ^^^^^^^^^^ value borrowed here after move
    |
 note: `Mine::make_string_bar` takes ownership of the receiver `self`, which moves `start`
-  --> $DIR/walk-struct-literal-with.rs:7:28
+  --> $DIR/ownership-struct-update-moved-error.rs:9:28
    |
-LL |     fn make_string_bar(mut self) -> Mine{
+LL |     fn make_string_bar(mut self) -> Mine {
    |                            ^^^^
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 

tests/ui/closures/no-capture-closure-call.rs

@@ -1,3 +1,5 @@
+//! Sanity check for no capture closures
+
 //@ run-pass
 
 pub fn main() {

tests/ui/drop/box-drop-unused-value-statement-regression.rs

@@ -1,12 +1,12 @@
-//@ run-pass
-// Issue #3878
-// Issue Name: Unused move causes a crash
-// Abstract: zero-fill to block after drop
-
+//! Regression test for a crash caused by an "unsused move"
+//! (specifically, a variable bound to a `Box` used as a statement)
+//! leading to incorrect memory zero-filling after drop.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/3878>.
 
-#![allow(path_statements)]
+//@ run-pass
 
 pub fn main() {
     let y: Box<_> = Box::new(1);
-    y;
+    drop(y);
 }

tests/ui/hashmap/hashset-enum-variant.rs

@@ -1,26 +1,27 @@
+//! Check for correct initialization of `HashSet` with enums. This is a regression test for a
+//! codegen bug that caused the `HashSet` to appear as if it contained one of each enum variant.
+//!
+//! Regression test for <https://github.com/rust-lang/rust/issues/42918>
+
 //@ run-pass
-//
-#![allow(dead_code)]
 //@ compile-flags: -O
 
+#![allow(dead_code)]
+
 use std::collections::HashSet;
 
 #[derive(PartialEq, Debug, Hash, Eq, Clone, PartialOrd, Ord)]
 enum MyEnum {
     E0,
-
     E1,
-
     E2,
     E3,
     E4,
-
     E5,
     E6,
     E7,
 }
 
-
 fn main() {
     use MyEnum::*;
     let s: HashSet<_> = [E4, E1].iter().cloned().collect();

tests/ui/io-checks/write-macro-error.rs

@@ -1,3 +1,6 @@
+//! Tests that errors from both the writer (`Write::write`) and formatter (`Display::fmt`)
+//! are correctly propagated: writer errors return `Err`, formatter errors cause panics.
+
 //@ run-pass
 //@ needs-unwind
 
@@ -24,7 +27,9 @@ impl Write for ErrorWriter {
         Err(Error::new(WRITER_ERROR, "not connected"))
     }
 
-    fn flush(&mut self) -> io::Result<()> { Ok(()) }
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
 }
 
 fn main() {
@@ -37,7 +42,8 @@ fn main() {
     let err = res.expect_err("formatter error did not lead to panic").downcast::<&str>().unwrap();
     assert!(
         err.contains("formatting trait implementation returned an error"),
-        "unexpected panic: {}", err
+        "unexpected panic: {}",
+        err
     );
 
     // Writer error when there's some string before the first `{}`
@@ -50,6 +56,7 @@ fn main() {
     let err = res.expect_err("formatter error did not lead to panic").downcast::<&str>().unwrap();
     assert!(
         err.contains("formatting trait implementation returned an error"),
-        "unexpected panic: {}", err
+        "unexpected panic: {}",
+        err
     );
 }

tests/ui/lang-items/lang-item-unknown-definition-error.rs

@@ -1,9 +1,11 @@
+//! Checks that compiler prevernt attempting to define an unrecognized or unknown lang item
+
 #![allow(unused)]
 #![feature(lang_items)]
 
 #[lang = "foo"]
 fn bar() -> ! {
-//~^^ ERROR definition of an unknown lang item: `foo`
+    //~^^ ERROR definition of an unknown lang item: `foo`
     loop {}
 }
 

tests/ui/lang-items/lang-item-unknown-definition-error.stderr

@@ -1,5 +1,5 @@
 error[E0522]: definition of an unknown lang item: `foo`
-  --> $DIR/unknown-language-item.rs:4:1
+  --> $DIR/lang-item-unknown-definition-error.rs:6:1
    |
 LL | #[lang = "foo"]
    | ^^^^^^^^^^^^^^^ definition of unknown lang item `foo`