Rollup merge of rust-lang#142668 - hkBst:less-static-mut, r=tgross35

vec_deque/fmt/vec tests: remove static mut

More rust-lang#125035.

r? ```@tgross35```

Author: tgross35

library/alloc/src/collections/linked_list/tests.rs

@@ -1,11 +1,11 @@
-use std::cell::Cell;
 use std::panic::{AssertUnwindSafe, catch_unwind};
 use std::thread;
 
 use rand::RngCore;
 
 use super::*;
 use crate::testing::crash_test::{CrashTestDummy, Panic};
+use crate::testing::macros::struct_with_counted_drop;
 use crate::vec::Vec;
 
 #[test]
@@ -1010,22 +1010,6 @@ fn extract_if_drop_panic_leak() {
     assert_eq!(d7.dropped(), 1);
 }
 
-macro_rules! struct_with_counted_drop {
-    ($struct_name:ident$(($elt_ty:ty))?, $drop_counter:ident $(=> $drop_stmt:expr)?) => {
-        thread_local! {static $drop_counter: Cell<u32> = Cell::new(0);}
-
-        struct $struct_name$(($elt_ty))?;
-
-        impl Drop for $struct_name {
-            fn drop(&mut self) {
-                $drop_counter.set($drop_counter.get() + 1);
-
-                $($drop_stmt(self))?
-            }
-        }
-    };
-}
-
 #[test]
 #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn extract_if_pred_panic_leak() {

library/alloc/src/collections/vec_deque/tests.rs

@@ -1,9 +1,7 @@
-// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
-#![allow(static_mut_refs)]
-
 use core::iter::TrustedLen;
 
 use super::*;
+use crate::testing::macros::struct_with_counted_drop;
 
 #[bench]
 fn bench_push_back_100(b: &mut test::Bencher) {
@@ -1086,36 +1084,24 @@ fn test_clone_from() {
 
 #[test]
 fn test_vec_deque_truncate_drop() {
-    static mut DROPS: u32 = 0;
-    #[derive(Clone)]
-    struct Elem(#[allow(dead_code)] i32);
-    impl Drop for Elem {
-        fn drop(&mut self) {
-            unsafe {
-                DROPS += 1;
-            }
-        }
-    }
+    struct_with_counted_drop!(Elem, DROPS);
 
-    let v = vec![Elem(1), Elem(2), Elem(3), Elem(4), Elem(5)];
-    for push_front in 0..=v.len() {
-        let v = v.clone();
-        let mut tester = VecDeque::with_capacity(5);
-        for (index, elem) in v.into_iter().enumerate() {
+    const LEN: usize = 5;
+    for push_front in 0..=LEN {
+        let mut tester = VecDeque::with_capacity(LEN);
+        for index in 0..LEN {
             if index < push_front {
-                tester.push_front(elem);
+                tester.push_front(Elem);
             } else {
-                tester.push_back(elem);
+                tester.push_back(Elem);
             }
         }
-        assert_eq!(unsafe { DROPS }, 0);
+        assert_eq!(DROPS.get(), 0);
         tester.truncate(3);
-        assert_eq!(unsafe { DROPS }, 2);
+        assert_eq!(DROPS.get(), 2);
         tester.truncate(0);
-        assert_eq!(unsafe { DROPS }, 5);
-        unsafe {
-            DROPS = 0;
-        }
+        assert_eq!(DROPS.get(), 5);
+        DROPS.set(0);
     }
 }
 

library/alloctests/testing/macros.rs

@@ -0,0 +1,37 @@
+macro_rules! struct_with_counted_drop {
+    ($struct_name:ident $(( $( $elt_ty:ty ),+ ))?, $drop_counter:ident $( => $drop_stmt:expr )? ) => {
+        thread_local! {static $drop_counter: ::core::cell::Cell<u32> = ::core::cell::Cell::new(0);}
+
+        #[derive(Clone, Debug, PartialEq)]
+        struct $struct_name $(( $( $elt_ty ),+ ))?;
+
+        impl ::std::ops::Drop for $struct_name {
+            fn drop(&mut self) {
+                $drop_counter.set($drop_counter.get() + 1);
+
+                $($drop_stmt(self))?
+            }
+        }
+    };
+    ($struct_name:ident $(( $( $elt_ty:ty ),+ ))?, $drop_counter:ident[ $drop_key:expr,$key_ty:ty ] $( => $drop_stmt:expr )? ) => {
+        thread_local! {
+            static $drop_counter: ::core::cell::RefCell<::std::collections::HashMap<$key_ty, u32>> =
+                ::core::cell::RefCell::new(::std::collections::HashMap::new());
+        }
+
+        #[derive(Clone, Debug, PartialEq)]
+        struct $struct_name $(( $( $elt_ty ),+ ))?;
+
+        impl ::std::ops::Drop for $struct_name {
+            fn drop(&mut self) {
+                $drop_counter.with_borrow_mut(|counter| {
+                    *counter.entry($drop_key(self)).or_default() += 1;
+                });
+
+                $($drop_stmt(self))?
+            }
+        }
+    };
+}
+
+pub(crate) use struct_with_counted_drop;

library/alloctests/testing/mod.rs

@@ -1,3 +1,4 @@
 pub(crate) mod crash_test;
+pub(crate) mod macros;
 pub(crate) mod ord_chaos;
 pub(crate) mod rng;

library/alloctests/tests/fmt.rs

@@ -1,6 +1,4 @@
 #![deny(warnings)]
-// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
-#![allow(static_mut_refs)]
 #![allow(unnecessary_transmutes)]
 
 use std::cell::RefCell;
@@ -285,19 +283,32 @@ fn test_format_args() {
     t!(s, "args were: hello world");
 }
 
+macro_rules! counter_fn {
+    ($name:ident) => {
+        fn $name() -> u32 {
+            thread_local! {static COUNTER: ::core::cell::Cell<u32> = ::core::cell::Cell::new(0);}
+
+            COUNTER.set(COUNTER.get() + 1);
+            COUNTER.get()
+        }
+    };
+}
+
 #[test]
 fn test_order() {
-    // Make sure format!() arguments are always evaluated in a left-to-right
-    // ordering
-    fn foo() -> isize {
-        static mut FOO: isize = 0;
-        unsafe {
-            FOO += 1;
-            FOO
-        }
-    }
+    // Make sure format!() arguments are always evaluated in a left-to-right ordering
+    counter_fn!(count);
+
     assert_eq!(
-        format!("{} {} {a} {b} {} {c}", foo(), foo(), foo(), a = foo(), b = foo(), c = foo()),
+        format!(
+            "{} {} {a} {b} {} {c}",
+            count(),
+            count(),
+            count(),
+            a = count(),
+            b = count(),
+            c = count()
+        ),
         "1 2 4 5 3 6".to_string()
     );
 }
@@ -306,14 +317,9 @@ fn test_order() {
 fn test_once() {
     // Make sure each argument are evaluated only once even though it may be
     // formatted multiple times
-    fn foo() -> isize {
-        static mut FOO: isize = 0;
-        unsafe {
-            FOO += 1;
-            FOO
-        }
-    }
-    assert_eq!(format!("{0} {0} {0} {a} {a} {a}", foo(), a = foo()), "1 1 1 2 2 2".to_string());
+    counter_fn!(count);
+
+    assert_eq!(format!("{0} {0} {0} {a} {a} {a}", count(), a = count()), "1 1 1 2 2 2".to_string());
 }
 
 #[test]

library/alloctests/tests/testing/mod.rs

@@ -1,2 +1,4 @@
 #[path = "../../testing/crash_test.rs"]
 pub mod crash_test;
+#[path = "../../testing/macros.rs"]
+pub mod macros;