Unrolled build for #134536

Rollup merge of #134536 - Urgau:fn-ptr-option, r=compiler-errors,traviscross

Lint on fn pointers comparisons in external macros

This PR extends the recently stabilized `unpredictable_function_pointer_comparisons` lint ~~to also lint on `Option<{function pointer}>` and~~ as well as linting in external macros (as to catch `assert_eq!` and others).

```rust
assert_eq!(Some::<FnPtr>(func), Some(func as unsafe extern "C" fn()));
//~^ WARN function pointer comparisons

#[derive(PartialEq, Eq)]
struct A {
    f: fn(),
    //~^ WARN function pointer comparisons
}
```

Fixes #134527

Author: rust-timer

compiler/rustc_lint/src/types.rs

@@ -196,7 +196,8 @@ declare_lint! {
     /// same address after being merged together.
     UNPREDICTABLE_FUNCTION_POINTER_COMPARISONS,
     Warn,
-    "detects unpredictable function pointer comparisons"
+    "detects unpredictable function pointer comparisons",
+    report_in_external_macro
 }
 
 #[derive(Copy, Clone, Default)]

library/core/src/task/wake.rs

@@ -104,6 +104,7 @@ impl RawWaker {
 /// synchronization. This is because [`LocalWaker`] is not thread safe itself, so it cannot
 /// be sent across threads.
 #[stable(feature = "futures_api", since = "1.36.0")]
+#[allow(unpredictable_function_pointer_comparisons)]
 #[derive(PartialEq, Copy, Clone, Debug)]
 pub struct RawWakerVTable {
     /// This function will be called when the [`RawWaker`] gets cloned, e.g. when

tests/ui/issues/issue-28561.rs

@@ -37,6 +37,7 @@ struct Array<T> {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[allow(unpredictable_function_pointer_comparisons)]
 struct Fn<A, B, C, D, E, F, G, H, I, J, K, L> {
     f00: fn(),
     f01: fn(A),

tests/ui/lint/fn-ptr-comparisons-some.rs

@@ -12,6 +12,6 @@ fn main() {
     let _ = Some::<FnPtr>(func) == Some(func as unsafe extern "C" fn());
     //~^ WARN function pointer comparisons
 
-    // Undecided as of https://github.com/rust-lang/rust/pull/134536
     assert_eq!(Some::<FnPtr>(func), Some(func as unsafe extern "C" fn()));
+    //~^ WARN function pointer comparisons
 }

tests/ui/lint/fn-ptr-comparisons-some.stderr

@@ -9,5 +9,16 @@ LL |     let _ = Some::<FnPtr>(func) == Some(func as unsafe extern "C" fn());
    = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
    = note: `#[warn(unpredictable_function_pointer_comparisons)]` on by default
 
-warning: 1 warning emitted
+warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
+  --> $DIR/fn-ptr-comparisons-some.rs:15:5
+   |
+LL |     assert_eq!(Some::<FnPtr>(func), Some(func as unsafe extern "C" fn()));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the address of the same function can vary between different codegen units
+   = note: furthermore, different functions could have the same address after being merged together
+   = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
+   = note: this warning originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: 2 warnings emitted
 

tests/ui/lint/fn-ptr-comparisons-weird.rs

@@ -1,5 +1,23 @@
 //@ check-pass
 
+#[derive(PartialEq, Eq)]
+struct A {
+    f: fn(),
+    //~^ WARN function pointer comparisons
+}
+
+#[allow(unpredictable_function_pointer_comparisons)]
+#[derive(PartialEq, Eq)]
+struct AllowedAbove {
+    f: fn(),
+}
+
+#[derive(PartialEq, Eq)]
+#[allow(unpredictable_function_pointer_comparisons)]
+struct AllowedBelow {
+    f: fn(),
+}
+
 fn main() {
     let f: fn() = main;
     let g: fn() = main;
@@ -12,4 +30,8 @@ fn main() {
     //~^ WARN function pointer comparisons
     let _ = f < g;
     //~^ WARN function pointer comparisons
+    let _ = assert_eq!(g, g);
+    //~^ WARN function pointer comparisons
+    let _ = assert_ne!(g, g);
+    //~^ WARN function pointer comparisons
 }

tests/ui/lint/fn-ptr-comparisons-weird.stderr

@@ -1,16 +1,29 @@
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons-weird.rs:7:13
+  --> $DIR/fn-ptr-comparisons-weird.rs:5:5
+   |
+LL | #[derive(PartialEq, Eq)]
+   |          --------- in this derive macro expansion
+LL | struct A {
+LL |     f: fn(),
+   |     ^^^^^^^
+   |
+   = note: the address of the same function can vary between different codegen units
+   = note: furthermore, different functions could have the same address after being merged together
+   = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
+   = note: `#[warn(unpredictable_function_pointer_comparisons)]` on by default
+
+warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
+  --> $DIR/fn-ptr-comparisons-weird.rs:25:13
    |
 LL |     let _ = f > g;
    |             ^^^^^
    |
    = note: the address of the same function can vary between different codegen units
    = note: furthermore, different functions could have the same address after being merged together
    = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
-   = note: `#[warn(unpredictable_function_pointer_comparisons)]` on by default
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons-weird.rs:9:13
+  --> $DIR/fn-ptr-comparisons-weird.rs:27:13
    |
 LL |     let _ = f >= g;
    |             ^^^^^^
@@ -20,7 +33,7 @@ LL |     let _ = f >= g;
    = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons-weird.rs:11:13
+  --> $DIR/fn-ptr-comparisons-weird.rs:29:13
    |
 LL |     let _ = f <= g;
    |             ^^^^^^
@@ -30,7 +43,7 @@ LL |     let _ = f <= g;
    = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons-weird.rs:13:13
+  --> $DIR/fn-ptr-comparisons-weird.rs:31:13
    |
 LL |     let _ = f < g;
    |             ^^^^^
@@ -39,5 +52,27 @@ LL |     let _ = f < g;
    = note: furthermore, different functions could have the same address after being merged together
    = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
 
-warning: 4 warnings emitted
+warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
+  --> $DIR/fn-ptr-comparisons-weird.rs:33:13
+   |
+LL |     let _ = assert_eq!(g, g);
+   |             ^^^^^^^^^^^^^^^^
+   |
+   = note: the address of the same function can vary between different codegen units
+   = note: furthermore, different functions could have the same address after being merged together
+   = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
+   = note: this warning originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
+  --> $DIR/fn-ptr-comparisons-weird.rs:35:13
+   |
+LL |     let _ = assert_ne!(g, g);
+   |             ^^^^^^^^^^^^^^^^
+   |
+   = note: the address of the same function can vary between different codegen units
+   = note: furthermore, different functions could have the same address after being merged together
+   = note: for more information visit <https://doc.rust-lang.org/nightly/core/ptr/fn.fn_addr_eq.html>
+   = note: this warning originates in the macro `assert_ne` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: 7 warnings emitted
 

tests/ui/lint/fn-ptr-comparisons.fixed

@@ -11,7 +11,6 @@ extern "C" fn c() {}
 
 extern "C" fn args(_a: i32) -> i32 { 0 }
 
-#[derive(PartialEq, Eq)]
 struct A {
     f: fn(),
 }
@@ -52,7 +51,6 @@ fn main() {
     let _ = std::ptr::fn_addr_eq(t, test as unsafe extern "C" fn());
     //~^ WARN function pointer comparisons
 
-    let _ = a1 == a2; // should not warn
     let _ = std::ptr::fn_addr_eq(a1.f, a2.f);
     //~^ WARN function pointer comparisons
 }

tests/ui/lint/fn-ptr-comparisons.rs

@@ -11,7 +11,6 @@ extern "C" fn c() {}
 
 extern "C" fn args(_a: i32) -> i32 { 0 }
 
-#[derive(PartialEq, Eq)]
 struct A {
     f: fn(),
 }
@@ -52,7 +51,6 @@ fn main() {
     let _ = t == test;
     //~^ WARN function pointer comparisons
 
-    let _ = a1 == a2; // should not warn
     let _ = a1.f == a2.f;
     //~^ WARN function pointer comparisons
 }

tests/ui/lint/fn-ptr-comparisons.stderr

@@ -1,5 +1,5 @@
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:26:13
+  --> $DIR/fn-ptr-comparisons.rs:25:13
    |
 LL |     let _ = f == a;
    |             ^^^^^^
@@ -15,7 +15,7 @@ LL +     let _ = std::ptr::fn_addr_eq(f, a as fn());
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:28:13
+  --> $DIR/fn-ptr-comparisons.rs:27:13
    |
 LL |     let _ = f != a;
    |             ^^^^^^
@@ -30,7 +30,7 @@ LL +     let _ = !std::ptr::fn_addr_eq(f, a as fn());
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:30:13
+  --> $DIR/fn-ptr-comparisons.rs:29:13
    |
 LL |     let _ = f == g;
    |             ^^^^^^
@@ -45,7 +45,7 @@ LL +     let _ = std::ptr::fn_addr_eq(f, g);
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:32:13
+  --> $DIR/fn-ptr-comparisons.rs:31:13
    |
 LL |     let _ = f == f;
    |             ^^^^^^
@@ -60,7 +60,7 @@ LL +     let _ = std::ptr::fn_addr_eq(f, f);
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:34:13
+  --> $DIR/fn-ptr-comparisons.rs:33:13
    |
 LL |     let _ = g == g;
    |             ^^^^^^
@@ -75,7 +75,7 @@ LL +     let _ = std::ptr::fn_addr_eq(g, g);
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:36:13
+  --> $DIR/fn-ptr-comparisons.rs:35:13
    |
 LL |     let _ = g == g;
    |             ^^^^^^
@@ -90,7 +90,7 @@ LL +     let _ = std::ptr::fn_addr_eq(g, g);
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:38:13
+  --> $DIR/fn-ptr-comparisons.rs:37:13
    |
 LL |     let _ = &g == &g;
    |             ^^^^^^^^
@@ -105,7 +105,7 @@ LL +     let _ = std::ptr::fn_addr_eq(g, g);
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:40:13
+  --> $DIR/fn-ptr-comparisons.rs:39:13
    |
 LL |     let _ = a as fn() == g;
    |             ^^^^^^^^^^^^^^
@@ -120,7 +120,7 @@ LL +     let _ = std::ptr::fn_addr_eq(a as fn(), g);
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:44:13
+  --> $DIR/fn-ptr-comparisons.rs:43:13
    |
 LL |     let _ = cfn == c;
    |             ^^^^^^^^
@@ -135,7 +135,7 @@ LL +     let _ = std::ptr::fn_addr_eq(cfn, c as extern "C" fn());
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:48:13
+  --> $DIR/fn-ptr-comparisons.rs:47:13
    |
 LL |     let _ = argsfn == args;
    |             ^^^^^^^^^^^^^^
@@ -150,7 +150,7 @@ LL +     let _ = std::ptr::fn_addr_eq(argsfn, args as extern "C" fn(i32) -> i32)
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:52:13
+  --> $DIR/fn-ptr-comparisons.rs:51:13
    |
 LL |     let _ = t == test;
    |             ^^^^^^^^^
@@ -165,7 +165,7 @@ LL +     let _ = std::ptr::fn_addr_eq(t, test as unsafe extern "C" fn());
    |
 
 warning: function pointer comparisons do not produce meaningful results since their addresses are not guaranteed to be unique
-  --> $DIR/fn-ptr-comparisons.rs:56:13
+  --> $DIR/fn-ptr-comparisons.rs:54:13
    |
 LL |     let _ = a1.f == a2.f;
    |             ^^^^^^^^^^^^