Rollup merge of #140036 - jieyouxu:ui-cleanup-4, r=compiler-errors

Advent of `tests/ui` (misc cleanups and improvements) [4/N]

Some `tests/ui/` housekeeping, to trim down number of tests directly under `tests/ui/`. Part of #133895.

### Review advice

- Best reviewed commit-by-commit.
- I can squash commits before merge, commits are separate to make it easier to review.

tests/ui/amdgpu-require-explicit-cpu.rs

@@ -1,18 +0,0 @@
-//@ revisions: nocpu cpu
-//@ no-prefer-dynamic
-//@ compile-flags: --crate-type=cdylib --target=amdgcn-amd-amdhsa
-//@ needs-llvm-components: amdgpu
-//@ needs-rust-lld
-//@[nocpu] build-fail
-//@[cpu] compile-flags: -Ctarget-cpu=gfx900
-//@[cpu] build-pass
-
-#![feature(no_core, lang_items)]
-#![no_core]
-
-#[lang="sized"]
-trait Sized {}
-
-pub fn foo() {}
-
-//[nocpu]~? ERROR target requires explicitly specifying a cpu with `-C target-cpu`

tests/ui/auto-instantiate.rs

@@ -1,13 +0,0 @@
-//@ run-pass
-
-#![allow(dead_code)]
-#[derive(Debug)]
-struct Pair<T, U> { a: T, b: U }
-struct Triple { x: isize, y: isize, z: isize }
-
-fn f<T,U>(x: T, y: U) -> Pair<T, U> { return Pair {a: x, b: y}; }
-
-pub fn main() {
-    println!("{}", f(Triple {x: 3, y: 4, z: 5}, 4).a.x);
-    println!("{}", f(5, 6).a);
-}

tests/ui/binop/augmented-assignments-cross-crate.rs

@@ -1,3 +1,5 @@
+//! Smoke test for overloaded compound assignments cross-crate.
+
 //@ run-pass
 //@ aux-build:augmented_assignments.rs
 

tests/ui/borrowck/augmented-assignments.rs

@@ -1,3 +1,6 @@
+//! Check that overloaded compound assignment operators respect usual borrowck rules and emit
+//! reasonable diagnostics.
+
 use std::ops::AddAssign;
 
 #[derive(Clone)]

tests/ui/borrowck/augmented-assignments.stderr

@@ -1,5 +1,5 @@
 error[E0505]: cannot move out of `x` because it is borrowed
-  --> $DIR/augmented-assignments.rs:17:5
+  --> $DIR/augmented-assignments.rs:20:5
    |
 LL |     let mut x = Int(1);
    |         ----- binding `x` declared here
@@ -10,7 +10,7 @@ LL |     x;
    |     ^ move out of `x` occurs here
 
 error[E0596]: cannot borrow `y` as mutable, as it is not declared as mutable
-  --> $DIR/augmented-assignments.rs:24:5
+  --> $DIR/augmented-assignments.rs:27:5
    |
 LL |     y
    |     ^ cannot borrow as mutable

tests/ui/inference/auto-instantiate.rs

@@ -0,0 +1,28 @@
+//! Check that type parameters in generic function arg position and in "nested" return type position
+//! can be inferred on an invocation of the generic function.
+//!
+//! See <https://github.com/rust-lang/rust/issues/45>.
+
+//@ run-pass
+
+#![allow(dead_code)]
+#[derive(Debug)]
+struct Pair<T, U> {
+    a: T,
+    b: U,
+}
+
+struct Triple {
+    x: isize,
+    y: isize,
+    z: isize,
+}
+
+fn f<T, U>(x: T, y: U) -> Pair<T, U> {
+    return Pair { a: x, b: y };
+}
+
+pub fn main() {
+    println!("{}", f(Triple {x: 3, y: 4, z: 5}, 4).a.x);
+    println!("{}", f(5, 6).a);
+}

tests/ui/target-cpu/explicit-target-cpu.avr_nocpu.stderr

@@ -0,0 +1,4 @@
+error: target requires explicitly specifying a cpu with `-C target-cpu`
+
+error: aborting due to 1 previous error
+

tests/ui/target-cpu/explicit-target-cpu.rs

@@ -0,0 +1,37 @@
+//! Check that certain target *requires* the user to specify a target CPU via `-C target-cpu`.
+
+//@ revisions: amdgcn_nocpu amdgcn_cpu
+
+//@[amdgcn_nocpu] compile-flags: --target=amdgcn-amd-amdhsa
+//@[amdgcn_nocpu] needs-llvm-components: amdgpu
+//@[amdgcn_nocpu] build-fail
+
+//@[amdgcn_cpu] compile-flags: --target=amdgcn-amd-amdhsa
+//@[amdgcn_cpu] needs-llvm-components: amdgpu
+//@[amdgcn_cpu] compile-flags: -Ctarget-cpu=gfx900
+//@[amdgcn_cpu] build-pass
+
+//@ revisions: avr_nocpu avr_cpu
+
+//@[avr_nocpu] compile-flags: --target=avr-none
+//@[avr_nocpu] needs-llvm-components: avr
+//@[avr_nocpu] build-fail
+
+//@[avr_cpu] compile-flags: --target=avr-none
+//@[avr_cpu] needs-llvm-components: avr
+//@[avr_cpu] compile-flags: -Ctarget-cpu=atmega328p
+//@[avr_cpu] build-pass
+
+#![crate_type = "rlib"]
+
+// FIXME(#140038): this can't use `minicore` yet because `minicore` doesn't currently propagate the
+// `-C target-cpu` for targets that *require* a `target-cpu` being specified.
+#![feature(no_core, lang_items)]
+#![no_core]
+
+#[lang="sized"]
+trait Sized {}
+
+pub fn foo() {}
+
+//[amdgcn_nocpu,avr_nocpu]~? ERROR target requires explicitly specifying a cpu with `-C target-cpu`