Rollup merge of #141793 - Kivooeo:test-reform, r=jieyouxu

`tests/ui`: A New Order [1/N]

not sure if i should say something about changes here, just part of #133895

but this is my very first time doing something like this, id love to keep contributing in this area later on, so any feedback is appreciated

also should say that im going to squash it after agreement on changes

r? `@jieyouxu`

mind if i name this PR series like "`tests/ui`: A New Order [N/N]", im not sure if it fits the project tone, so id like your approval first — but i think it sounds really neat (Star Wars reference)

this could be a first part :)

Author: matthiaskrgr

tests/ui/autoderef-full-lval.rs

@@ -0,0 +1,35 @@
+//! Tests that auto-dereferencing does not allow addition of `Box<isize>` values.
+//!
+//! This test ensures that `Box<isize>` fields in structs (`Clam` and `Fish`) are not
+//! automatically dereferenced to `isize` during addition operations, as `Box<isize>`
+//! does not implement the `Add` trait.
+
+struct Clam {
+    x: Box<isize>,
+    y: Box<isize>,
+}
+
+struct Fish {
+    a: Box<isize>,
+}
+
+fn main() {
+    let a: Clam = Clam {
+        x: Box::new(1),
+        y: Box::new(2),
+    };
+    let b: Clam = Clam {
+        x: Box::new(10),
+        y: Box::new(20),
+    };
+    let z: isize = a.x + b.y;
+    //~^ ERROR cannot add `Box<isize>` to `Box<isize>`
+    println!("{}", z);
+    assert_eq!(z, 21);
+    let forty: Fish = Fish { a: Box::new(40) };
+    let two: Fish = Fish { a: Box::new(2) };
+    let answer: isize = forty.a + two.a;
+    //~^ ERROR cannot add `Box<isize>` to `Box<isize>`
+    println!("{}", answer);
+    assert_eq!(answer, 42);
+}

tests/ui/autoref-autoderef/autoderef-box-no-add.rs

@@ -1,5 +1,5 @@
 error[E0369]: cannot add `Box<isize>` to `Box<isize>`
-  --> $DIR/autoderef-full-lval.rs:15:24
+  --> $DIR/autoderef-box-no-add.rs:25:24
    |
 LL |     let z: isize = a.x + b.y;
    |                    --- ^ --- Box<isize>
@@ -13,7 +13,7 @@ note: the foreign item type `Box<isize>` doesn't implement `Add`
    = note: not implement `Add`
 
 error[E0369]: cannot add `Box<isize>` to `Box<isize>`
-  --> $DIR/autoderef-full-lval.rs:21:33
+  --> $DIR/autoderef-box-no-add.rs:31:33
    |
 LL |     let answer: isize = forty.a + two.a;
    |                         ------- ^ ----- Box<isize>

tests/ui/autoderef-full-lval.stderr renamed to tests/ui/autoref-autoderef/autoderef-box-no-add.stderr

@@ -1,3 +1,7 @@
+//! Tests that bare functions implement the `FnMut` trait.
+//!
+//! See <https://github.com/rust-lang/rust/issues/15448>.
+
 //@ run-pass
 
 fn call_f<F:FnMut()>(mut f: F) {

tests/ui/bare-fn-implements-fn-mut.rs renamed to tests/ui/functions-closures/bare-fn-implements-fn-mut.rs

@@ -1,5 +1,7 @@
+//! Test that valid large numeric literals do not trigger the `overflowing_literals` lint.
+
 //@ run-pass
-// Catch mistakes in the overflowing literals lint.
+
 #![deny(overflowing_literals)]
 
 pub fn main() {

tests/ui/big-literals.rs renamed to tests/ui/lint/overflowing-literals-valid.rs

@@ -1,8 +1,7 @@
-fn main() {
-
-    // Testing that method lookup does not automatically borrow
-    // vectors to slices then automatically create a self reference.
+//! Test that method resolution does not autoderef `Vec`
+//! into a slice or perform additional autorefs.
 
+fn main() {
     let mut a = vec![0];
     a.test_mut(); //~ ERROR no method named `test_mut` found
     a.test(); //~ ERROR no method named `test` found

tests/ui/auto-ref-slice-plus-ref.rs renamed to tests/ui/methods/vec-autoderef-autoref.rs

@@ -1,53 +1,53 @@
 error[E0599]: no method named `test_mut` found for struct `Vec<{integer}>` in the current scope
-  --> $DIR/auto-ref-slice-plus-ref.rs:7:7
+  --> $DIR/vec-autoderef-autoref.rs:6:7
    |
 LL |     a.test_mut();
    |       ^^^^^^^^
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `MyIter` defines an item `test_mut`, perhaps you need to implement it
-  --> $DIR/auto-ref-slice-plus-ref.rs:14:1
+  --> $DIR/vec-autoderef-autoref.rs:13:1
    |
 LL | trait MyIter {
    | ^^^^^^^^^^^^
 help: there is a method `get_mut` with a similar name, but with different arguments
   --> $SRC_DIR/core/src/slice/mod.rs:LL:COL
 
 error[E0599]: no method named `test` found for struct `Vec<{integer}>` in the current scope
-  --> $DIR/auto-ref-slice-plus-ref.rs:8:7
+  --> $DIR/vec-autoderef-autoref.rs:7:7
    |
 LL |     a.test();
    |       ^^^^ method not found in `Vec<{integer}>`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `MyIter` defines an item `test`, perhaps you need to implement it
-  --> $DIR/auto-ref-slice-plus-ref.rs:14:1
+  --> $DIR/vec-autoderef-autoref.rs:13:1
    |
 LL | trait MyIter {
    | ^^^^^^^^^^^^
 
 error[E0599]: no method named `test` found for array `[{integer}; 1]` in the current scope
-  --> $DIR/auto-ref-slice-plus-ref.rs:10:11
+  --> $DIR/vec-autoderef-autoref.rs:9:11
    |
 LL |     ([1]).test();
    |           ^^^^ method not found in `[{integer}; 1]`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `MyIter` defines an item `test`, perhaps you need to implement it
-  --> $DIR/auto-ref-slice-plus-ref.rs:14:1
+  --> $DIR/vec-autoderef-autoref.rs:13:1
    |
 LL | trait MyIter {
    | ^^^^^^^^^^^^
 
 error[E0599]: no method named `test` found for reference `&[{integer}; 1]` in the current scope
-  --> $DIR/auto-ref-slice-plus-ref.rs:11:12
+  --> $DIR/vec-autoderef-autoref.rs:10:12
    |
 LL |     (&[1]).test();
    |            ^^^^ method not found in `&[{integer}; 1]`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `MyIter` defines an item `test`, perhaps you need to implement it
-  --> $DIR/auto-ref-slice-plus-ref.rs:14:1
+  --> $DIR/vec-autoderef-autoref.rs:13:1
    |
 LL | trait MyIter {
    | ^^^^^^^^^^^^

tests/ui/auto-ref-slice-plus-ref.stderr renamed to tests/ui/methods/vec-autoderef-autoref.stderr

@@ -1,3 +1,5 @@
+//! Check that a bare string literal is typed as a `&'static str` and is usable.
+
 //@ run-pass
 
 pub fn main() {