Rollup of 4 pull requests

compiler/rustc_lint/src/builtin.rs

@@ -58,6 +58,7 @@ use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::GenericArgKind;
+use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::TypeVisitableExt;
 use rustc_middle::ty::{self, Ty, TyCtxt, VariantDef};
 use rustc_session::config::ExpectedValues;
@@ -68,6 +69,7 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, InnerSpan, Span};
 use rustc_target::abi::Abi;
 use rustc_trait_selection::infer::{InferCtxtExt, TyCtxtInferExt};
+use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use rustc_trait_selection::traits::{self, misc::type_allowed_to_implement_copy};
 
 use crate::nonstandard_style::{method_context, MethodLateContext};
@@ -673,6 +675,9 @@ impl<'tcx> LateLintPass<'tcx> for MissingCopyImplementations {
         if ty.is_copy_modulo_regions(cx.tcx, param_env) {
             return;
         }
+        if type_implements_negative_copy_modulo_regions(cx.tcx, ty, param_env) {
+            return;
+        }
 
         // We shouldn't recommend implementing `Copy` on stateful things,
         // such as iterators.
@@ -708,6 +713,24 @@ impl<'tcx> LateLintPass<'tcx> for MissingCopyImplementations {
     }
 }
 
+/// Check whether a `ty` has a negative `Copy` implementation, ignoring outlives constraints.
+fn type_implements_negative_copy_modulo_regions<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    ty: Ty<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
+) -> bool {
+    let trait_ref = ty::TraitRef::new(tcx, tcx.require_lang_item(hir::LangItem::Copy, None), [ty]);
+    let pred = ty::TraitPredicate { trait_ref, polarity: ty::ImplPolarity::Negative };
+    let obligation = traits::Obligation {
+        cause: traits::ObligationCause::dummy(),
+        param_env,
+        recursion_depth: 0,
+        predicate: ty::Binder::dummy(pred).to_predicate(tcx),
+    };
+
+    tcx.infer_ctxt().build().predicate_must_hold_modulo_regions(&obligation)
+}
+
 declare_lint! {
     /// The `missing_debug_implementations` lint detects missing
     /// implementations of [`fmt::Debug`] for public types.

library/core/src/clone.rs

@@ -86,6 +86,46 @@
 /// }
 /// ```
 ///
+/// If we `derive`:
+///
+/// ```
+/// #[derive(Copy, Clone)]
+/// struct Generate<T>(fn() -> T);
+/// ```
+///
+/// the auto-derived implementations will have unnecessary `T: Copy` and `T: Clone` bounds:
+///
+/// ```
+/// # struct Generate<T>(fn() -> T);
+///
+/// // Automatically derived
+/// impl<T: Copy> Copy for Generate<T> { }
+///
+/// // Automatically derived
+/// impl<T: Clone> Clone for Generate<T> {
+///     fn clone(&self) -> Generate<T> {
+///         Generate(Clone::clone(&self.0))
+///     }
+/// }
+/// ```
+///
+/// The bounds are unnecessary because clearly the function itself should be
+/// copy- and cloneable even if its return type is not:
+///
+/// ```compile_fail,E0599
+/// #[derive(Copy, Clone)]
+/// struct Generate<T>(fn() -> T);
+///
+/// struct NotCloneable;
+///
+/// fn generate_not_cloneable() -> NotCloneable {
+///     NotCloneable
+/// }
+///
+/// Generate(generate_not_cloneable).clone(); // error: trait bounds were not satisfied
+/// // Note: With the manual implementations the above line will compile.
+/// ```
+///
 /// ## Additional implementors
 ///
 /// In addition to the [implementors listed below][impls],

library/std/src/env.rs

@@ -178,7 +178,8 @@ impl Iterator for Vars {
 #[stable(feature = "std_debug", since = "1.16.0")]
 impl fmt::Debug for Vars {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("Vars").finish_non_exhaustive()
+        let Self { inner: VarsOs { inner } } = self;
+        f.debug_struct("Vars").field("inner", inner).finish()
     }
 }
 
@@ -196,7 +197,8 @@ impl Iterator for VarsOs {
 #[stable(feature = "std_debug", since = "1.16.0")]
 impl fmt::Debug for VarsOs {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("VarOs").finish_non_exhaustive()
+        let Self { inner } = self;
+        f.debug_struct("VarsOs").field("inner", inner).finish()
     }
 }
 
@@ -829,7 +831,8 @@ impl DoubleEndedIterator for Args {
 #[stable(feature = "std_debug", since = "1.16.0")]
 impl fmt::Debug for Args {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("Args").field("inner", &self.inner.inner).finish()
+        let Self { inner: ArgsOs { inner } } = self;
+        f.debug_struct("Args").field("inner", inner).finish()
     }
 }
 
@@ -870,7 +873,8 @@ impl DoubleEndedIterator for ArgsOs {
 #[stable(feature = "std_debug", since = "1.16.0")]
 impl fmt::Debug for ArgsOs {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("ArgsOs").field("inner", &self.inner).finish()
+        let Self { inner } = self;
+        f.debug_struct("ArgsOs").field("inner", inner).finish()
     }
 }
 

library/std/src/env/tests.rs

@@ -95,8 +95,28 @@ fn args_debug() {
         format!("Args {{ inner: {:?} }}", args().collect::<Vec<_>>()),
         format!("{:?}", args())
     );
+}
+
+#[test]
+fn args_os_debug() {
     assert_eq!(
         format!("ArgsOs {{ inner: {:?} }}", args_os().collect::<Vec<_>>()),
         format!("{:?}", args_os())
     );
 }
+
+#[test]
+fn vars_debug() {
+    assert_eq!(
+        format!("Vars {{ inner: {:?} }}", vars().collect::<Vec<_>>()),
+        format!("{:?}", vars())
+    );
+}
+
+#[test]
+fn vars_os_debug() {
+    assert_eq!(
+        format!("VarsOs {{ inner: {:?} }}", vars_os().collect::<Vec<_>>()),
+        format!("{:?}", vars_os())
+    );
+}

library/std/src/sys/hermit/os.rs

@@ -112,6 +112,13 @@ pub struct Env {
     iter: vec::IntoIter<(OsString, OsString)>,
 }
 
+impl fmt::Debug for Env {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { iter } = self;
+        f.debug_list().entries(iter.as_slice()).finish()
+    }
+}
+
 impl !Send for Env {}
 impl !Sync for Env {}
 

library/std/src/sys/solid/os.rs

@@ -85,6 +85,13 @@ pub struct Env {
     iter: vec::IntoIter<(OsString, OsString)>,
 }
 
+impl fmt::Debug for Env {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { iter } = self;
+        f.debug_list().entries(iter.as_slice()).finish()
+    }
+}
+
 impl !Send for Env {}
 impl !Sync for Env {}
 

library/std/src/sys/unix/os.rs

@@ -495,6 +495,13 @@ pub struct Env {
     iter: vec::IntoIter<(OsString, OsString)>,
 }
 
+impl fmt::Debug for Env {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { iter } = self;
+        f.debug_list().entries(iter.as_slice()).finish()
+    }
+}
+
 impl !Send for Env {}
 impl !Sync for Env {}
 

library/std/src/sys/unsupported/os.rs

@@ -65,10 +65,18 @@ pub fn current_exe() -> io::Result<PathBuf> {
 
 pub struct Env(!);
 
+impl fmt::Debug for Env {
+    fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self(inner) = self;
+        match *inner {}
+    }
+}
+
 impl Iterator for Env {
     type Item = (OsString, OsString);
     fn next(&mut self) -> Option<(OsString, OsString)> {
-        self.0
+        let Self(inner) = self;
+        match *inner {}
     }
 }
 

library/std/src/sys/wasi/os.rs

@@ -142,10 +142,18 @@ impl StdError for JoinPathsError {
 pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
 }
+
 pub struct Env {
     iter: vec::IntoIter<(OsString, OsString)>,
 }
 
+impl fmt::Debug for Env {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { iter } = self;
+        f.debug_list().entries(iter.as_slice()).finish()
+    }
+}
+
 impl !Send for Env {}
 impl !Sync for Env {}
 

library/std/src/sys/windows/os.rs

@@ -85,25 +85,45 @@ pub fn error_string(mut errnum: i32) -> String {
 
 pub struct Env {
     base: c::LPWCH,
-    cur: c::LPWCH,
+    iter: EnvIterator,
+}
+
+impl fmt::Debug for Env {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { base: _, iter } = self;
+        f.debug_list().entries(iter.clone()).finish()
+    }
 }
 
 impl Iterator for Env {
     type Item = (OsString, OsString);
 
     fn next(&mut self) -> Option<(OsString, OsString)> {
+        let Self { base: _, iter } = self;
+        iter.next()
+    }
+}
+
+#[derive(Clone)]
+struct EnvIterator(c::LPWCH);
+
+impl Iterator for EnvIterator {
+    type Item = (OsString, OsString);
+
+    fn next(&mut self) -> Option<(OsString, OsString)> {
+        let Self(cur) = self;
         loop {
             unsafe {
-                if *self.cur == 0 {
+                if **cur == 0 {
                     return None;
                 }
-                let p = self.cur as *const u16;
+                let p = *cur as *const u16;
                 let mut len = 0;
                 while *p.add(len) != 0 {
                     len += 1;
                 }
                 let s = slice::from_raw_parts(p, len);
-                self.cur = self.cur.add(len + 1);
+                *cur = cur.add(len + 1);
 
                 // Windows allows environment variables to start with an equals
                 // symbol (in any other position, this is the separator between
@@ -137,7 +157,7 @@ pub fn env() -> Env {
         if ch.is_null() {
             panic!("failure getting env string from OS: {}", io::Error::last_os_error());
         }
-        Env { base: ch, cur: ch }
+        Env { base: ch, iter: EnvIterator(ch) }
     }
 }
 

src/tools/tidy/src/fluent_alphabetical.rs

@@ -23,7 +23,7 @@ fn check_alphabetic(filename: &str, fluent: &str, bad: &mut bool) {
                 tidy_error!(
                     bad,
                     "{filename}: message `{}` appears before `{}`, but is alphabetically later than it
-run tidy with `--bless` to sort the file correctly",
+run `./x.py test tidy --bless` to sort the file correctly",
                     name.as_str(),
                     next.as_str()
                 );

tests/ui/lint/missing-copy-implementations-negative-copy.rs

@@ -0,0 +1,15 @@
+// Regression test for issue #101980.
+// Ensure that we don't suggest impl'ing `Copy` for a type if it already impl's `!Copy`.
+
+// check-pass
+
+#![feature(negative_impls)]
+#![deny(missing_copy_implementations)]
+
+pub struct Struct {
+    pub field: i32,
+}
+
+impl !Copy for Struct {}
+
+fn main() {}