Allow storing format_args!() in a variable

compiler/rustc_ast_lowering/src/expr.rs

@@ -2289,12 +2289,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
         span: Span,
         elements: &'hir [hir::Expr<'hir>],
     ) -> hir::Expr<'hir> {
-        let addrof = hir::ExprKind::AddrOf(
-            hir::BorrowKind::Ref,
-            hir::Mutability::Not,
-            self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements))),
-        );
-        self.expr(span, addrof)
+        let array = self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements)));
+        self.expr_ref(span, array)
+    }
+
+    pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
+        self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
     }
 
     pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {

compiler/rustc_ast_lowering/src/format.rs

@@ -1,7 +1,5 @@
-use core::ops::ControlFlow;
 use std::borrow::Cow;
 
-use rustc_ast::visit::Visitor;
 use rustc_ast::*;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_hir as hir;
@@ -476,77 +474,52 @@ fn expand_format_args<'hir>(
         return hir::ExprKind::Call(new, new_args);
     }
 
-    // If the args array contains exactly all the original arguments once,
-    // in order, we can use a simple array instead of a `match` construction.
-    // However, if there's a yield point in any argument except the first one,
-    // we don't do this, because an Argument cannot be kept across yield points.
-    //
-    // This is an optimization, speeding up compilation about 1-2% in some cases.
-    // See https://github.com/rust-lang/rust/pull/106770#issuecomment-1380790609
-    let use_simple_array = argmap.len() == arguments.len()
-        && argmap.iter().enumerate().all(|(i, (&(j, _), _))| i == j)
-        && arguments.iter().skip(1).all(|arg| !may_contain_yield_point(&arg.expr));
-
-    let args = if arguments.is_empty() {
+    let (let_statements, args) = if arguments.is_empty() {
         // Generate:
-        //    &<core::fmt::Argument>::none()
+        //     []
+        (vec![], ctx.arena.alloc(ctx.expr(macsp, hir::ExprKind::Array(&[]))))
+    } else if argmap.len() == 1 && arguments.len() == 1 {
+        // Only one argument, so we don't need to make the `args` tuple.
         //
-        // Note:
-        //     `none()` just returns `[]`. We use `none()` rather than `[]` to limit the lifetime.
-        //
-        //     This makes sure that this still fails to compile, even when the argument is inlined:
-        //
-        //     ```
-        //     let f = format_args!("{}", "a");
-        //     println!("{f}"); // error E0716
-        //     ```
-        //
-        //     Cases where keeping the object around is allowed, such as `format_args!("a")`,
-        //     are handled above by the `allow_const` case.
-        let none_fn = ctx.arena.alloc(ctx.expr_lang_item_type_relative(
-            macsp,
-            hir::LangItem::FormatArgument,
-            sym::none,
-        ));
-        let none = ctx.expr_call(macsp, none_fn, &[]);
-        ctx.expr(macsp, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, none))
-    } else if use_simple_array {
         // Generate:
-        //     &[
-        //         <core::fmt::Argument>::new_display(&arg0),
-        //         <core::fmt::Argument>::new_lower_hex(&arg1),
-        //         <core::fmt::Argument>::new_debug(&arg2),
-        //         …
-        //     ]
-        let elements = ctx.arena.alloc_from_iter(arguments.iter().zip(argmap).map(
-            |(arg, ((_, ty), placeholder_span))| {
+        //     super let args = [<core::fmt::Argument>::new_display(&arg)];
+        let args = ctx.arena.alloc_from_iter(argmap.iter().map(
+            |(&(arg_index, ty), &placeholder_span)| {
+                let arg = &arguments[arg_index];
                 let placeholder_span =
                     placeholder_span.unwrap_or(arg.expr.span).with_ctxt(macsp.ctxt());
-                let arg_span = match arg.kind {
-                    FormatArgumentKind::Captured(_) => placeholder_span,
-                    _ => arg.expr.span.with_ctxt(macsp.ctxt()),
-                };
                 let arg = ctx.lower_expr(&arg.expr);
-                let ref_arg = ctx.arena.alloc(ctx.expr(
-                    arg_span,
-                    hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, arg),
-                ));
+                let ref_arg = ctx.arena.alloc(ctx.expr_ref(arg.span.with_ctxt(macsp.ctxt()), arg));
                 make_argument(ctx, placeholder_span, ref_arg, ty)
             },
         ));
-        ctx.expr_array_ref(macsp, elements)
+        let args = ctx.arena.alloc(ctx.expr(macsp, hir::ExprKind::Array(args)));
+        let args_ident = Ident::new(sym::args, macsp);
+        let (args_pat, args_hir_id) = ctx.pat_ident(macsp, args_ident);
+        let let_statement = ctx.stmt_super_let_pat(macsp, args_pat, Some(args));
+        (vec![let_statement], ctx.arena.alloc(ctx.expr_ident_mut(macsp, args_ident, args_hir_id)))
     } else {
         // Generate:
-        //     &match (&arg0, &arg1, &…) {
-        //         args => [
-        //             <core::fmt::Argument>::new_display(args.0),
-        //             <core::fmt::Argument>::new_lower_hex(args.1),
-        //             <core::fmt::Argument>::new_debug(args.0),
-        //             …
-        //         ]
-        //     }
+        //     super let args = (&arg0, &arg1, &…);
         let args_ident = Ident::new(sym::args, macsp);
         let (args_pat, args_hir_id) = ctx.pat_ident(macsp, args_ident);
+        let elements = ctx.arena.alloc_from_iter(arguments.iter().map(|arg| {
+            let arg_expr = ctx.lower_expr(&arg.expr);
+            ctx.expr(
+                arg.expr.span.with_ctxt(macsp.ctxt()),
+                hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, arg_expr),
+            )
+        }));
+        let args_tuple = ctx.arena.alloc(ctx.expr(macsp, hir::ExprKind::Tup(elements)));
+        let let_statement_1 = ctx.stmt_super_let_pat(macsp, args_pat, Some(args_tuple));
+
+        // Generate:
+        //     super let args = [
+        //         <core::fmt::Argument>::new_display(args.0),
+        //         <core::fmt::Argument>::new_lower_hex(args.1),
+        //         <core::fmt::Argument>::new_debug(args.0),
+        //         …
+        //     ];
         let args = ctx.arena.alloc_from_iter(argmap.iter().map(
             |(&(arg_index, ty), &placeholder_span)| {
                 let arg = &arguments[arg_index];
@@ -567,58 +540,47 @@ fn expand_format_args<'hir>(
                 make_argument(ctx, placeholder_span, arg, ty)
             },
         ));
-        let elements = ctx.arena.alloc_from_iter(arguments.iter().map(|arg| {
-            let arg_expr = ctx.lower_expr(&arg.expr);
-            ctx.expr(
-                arg.expr.span.with_ctxt(macsp.ctxt()),
-                hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, arg_expr),
-            )
-        }));
-        let args_tuple = ctx.arena.alloc(ctx.expr(macsp, hir::ExprKind::Tup(elements)));
-        let array = ctx.arena.alloc(ctx.expr(macsp, hir::ExprKind::Array(args)));
-        let match_arms = ctx.arena.alloc_from_iter([ctx.arm(args_pat, array)]);
-        let match_expr = ctx.arena.alloc(ctx.expr_match(
-            macsp,
-            args_tuple,
-            match_arms,
-            hir::MatchSource::FormatArgs,
-        ));
-        ctx.expr(
-            macsp,
-            hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, match_expr),
+        let args = ctx.arena.alloc(ctx.expr(macsp, hir::ExprKind::Array(args)));
+        let (args_pat, args_hir_id) = ctx.pat_ident(macsp, args_ident);
+        let let_statement_2 = ctx.stmt_super_let_pat(macsp, args_pat, Some(args));
+        (
+            vec![let_statement_1, let_statement_2],
+            ctx.arena.alloc(ctx.expr_ident_mut(macsp, args_ident, args_hir_id)),
         )
     };
 
-    if let Some(format_options) = format_options {
+    // Generate:
+    //     &args
+    let args = ctx.expr_ref(macsp, args);
+
+    let call = if let Some(format_options) = format_options {
         // Generate:
-        //     <core::fmt::Arguments>::new_v1_formatted(
-        //         lit_pieces,
-        //         args,
-        //         format_options,
-        //         unsafe { ::core::fmt::UnsafeArg::new() }
-        //     )
+        //     unsafe {
+        //         <core::fmt::Arguments>::new_v1_formatted(
+        //             lit_pieces,
+        //             args,
+        //             format_options,
+        //         )
+        //     }
         let new_v1_formatted = ctx.arena.alloc(ctx.expr_lang_item_type_relative(
             macsp,
             hir::LangItem::FormatArguments,
             sym::new_v1_formatted,
         ));
-        let unsafe_arg_new = ctx.arena.alloc(ctx.expr_lang_item_type_relative(
-            macsp,
-            hir::LangItem::FormatUnsafeArg,
-            sym::new,
-        ));
-        let unsafe_arg_new_call = ctx.expr_call(macsp, unsafe_arg_new, &[]);
+        let args = ctx.arena.alloc_from_iter([lit_pieces, args, format_options]);
+        let call = ctx.expr_call(macsp, new_v1_formatted, args);
         let hir_id = ctx.next_id();
-        let unsafe_arg = ctx.expr_block(ctx.arena.alloc(hir::Block {
-            stmts: &[],
-            expr: Some(unsafe_arg_new_call),
-            hir_id,
-            rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
-            span: macsp,
-            targeted_by_break: false,
-        }));
-        let args = ctx.arena.alloc_from_iter([lit_pieces, args, format_options, unsafe_arg]);
-        hir::ExprKind::Call(new_v1_formatted, args)
+        hir::ExprKind::Block(
+            ctx.arena.alloc(hir::Block {
+                stmts: &[],
+                expr: Some(call),
+                hir_id,
+                rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
+                span: macsp,
+                targeted_by_break: false,
+            }),
+            None,
+        )
     } else {
         // Generate:
         //     <core::fmt::Arguments>::new_v1(
@@ -632,35 +594,21 @@ fn expand_format_args<'hir>(
         ));
         let new_args = ctx.arena.alloc_from_iter([lit_pieces, args]);
         hir::ExprKind::Call(new_v1, new_args)
-    }
-}
-
-fn may_contain_yield_point(e: &ast::Expr) -> bool {
-    struct MayContainYieldPoint;
-
-    impl Visitor<'_> for MayContainYieldPoint {
-        type Result = ControlFlow<()>;
-
-        fn visit_expr(&mut self, e: &ast::Expr) -> ControlFlow<()> {
-            if let ast::ExprKind::Await(_, _) | ast::ExprKind::Yield(_) = e.kind {
-                ControlFlow::Break(())
-            } else {
-                visit::walk_expr(self, e)
-            }
-        }
-
-        fn visit_mac_call(&mut self, _: &ast::MacCall) -> ControlFlow<()> {
-            // Macros should be expanded at this point.
-            unreachable!("unexpanded macro in ast lowering");
-        }
+    };
 
-        fn visit_item(&mut self, _: &ast::Item) -> ControlFlow<()> {
-            // Do not recurse into nested items.
-            ControlFlow::Continue(())
-        }
+    if !let_statements.is_empty() {
+        // Generate:
+        //     {
+        //         super let …
+        //         super let …
+        //         <core::fmt::Arguments>::new_…(…)
+        //     }
+        let call = ctx.arena.alloc(ctx.expr(macsp, call));
+        let block = ctx.block_all(macsp, ctx.arena.alloc_from_iter(let_statements), Some(call));
+        hir::ExprKind::Block(block, None)
+    } else {
+        call
     }
-
-    MayContainYieldPoint.visit_expr(e).is_break()
 }
 
 fn for_all_argument_indexes(template: &mut [FormatArgsPiece], mut f: impl FnMut(&mut usize)) {

compiler/rustc_ast_lowering/src/lib.rs

@@ -2301,6 +2301,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.stmt(span, hir::StmtKind::Let(self.arena.alloc(local)))
     }
 
+    fn stmt_super_let_pat(
+        &mut self,
+        span: Span,
+        pat: &'hir hir::Pat<'hir>,
+        init: Option<&'hir hir::Expr<'hir>>,
+    ) -> hir::Stmt<'hir> {
+        let hir_id = self.next_id();
+        let local = hir::LetStmt {
+            super_: Some(span),
+            hir_id,
+            init,
+            pat,
+            els: None,
+            source: hir::LocalSource::Normal,
+            span: self.lower_span(span),
+            ty: None,
+        };
+        self.stmt(span, hir::StmtKind::Let(self.arena.alloc(local)))
+    }
+
     fn block_expr(&mut self, expr: &'hir hir::Expr<'hir>) -> &'hir hir::Block<'hir> {
         self.block_all(expr.span, &[], Some(expr))
     }

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -3201,14 +3201,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         let expr_ty: Option<Ty<'_>> =
                             visitor.prop_expr.map(|expr| typeck_results.expr_ty(expr).peel_refs());
 
-                        let is_format_arguments_item = if let Some(expr_ty) = expr_ty
-                            && let ty::Adt(adt, _) = expr_ty.kind()
-                        {
-                            self.infcx.tcx.is_lang_item(adt.did(), LangItem::FormatArguments)
-                        } else {
-                            false
-                        };
-
                         if visitor.found == 0
                             && stmt.span.contains(proper_span)
                             && let Some(p) = sm.span_to_margin(stmt.span)
@@ -3236,25 +3228,17 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                                 ""
                             };
 
-                            if !is_format_arguments_item {
-                                let addition = format!(
-                                    "let {}binding = {};\n{}",
-                                    mutability,
-                                    s,
-                                    " ".repeat(p)
-                                );
-                                err.multipart_suggestion_verbose(
-                                    msg,
-                                    vec![
-                                        (stmt.span.shrink_to_lo(), addition),
-                                        (proper_span, "binding".to_string()),
-                                    ],
-                                    Applicability::MaybeIncorrect,
-                                );
-                            } else {
-                                err.note("the result of `format_args!` can only be assigned directly if no placeholders in its arguments are used");
-                                err.note("to learn more, visit <https://doc.rust-lang.org/std/macro.format_args.html>");
-                            }
+                            let addition =
+                                format!("let {}binding = {};\n{}", mutability, s, " ".repeat(p));
+                            err.multipart_suggestion_verbose(
+                                msg,
+                                vec![
+                                    (stmt.span.shrink_to_lo(), addition),
+                                    (proper_span, "binding".to_string()),
+                                ],
+                                Applicability::MaybeIncorrect,
+                            );
+
                             suggested = true;
                             break;
                         }

library/core/src/fmt/rt.rs

@@ -183,38 +183,6 @@ impl Argument<'_> {
             ArgumentType::Placeholder { .. } => None,
         }
     }
-
-    /// Used by `format_args` when all arguments are gone after inlining,
-    /// when using `&[]` would incorrectly allow for a bigger lifetime.
-    ///
-    /// This fails without format argument inlining, and that shouldn't be different
-    /// when the argument is inlined:
-    ///
-    /// ```compile_fail,E0716
-    /// let f = format_args!("{}", "a");
-    /// println!("{f}");
-    /// ```
-    #[inline]
-    pub const fn none() -> [Self; 0] {
-        []
-    }
-}
-
-/// This struct represents the unsafety of constructing an `Arguments`.
-/// It exists, rather than an unsafe function, in order to simplify the expansion
-/// of `format_args!(..)` and reduce the scope of the `unsafe` block.
-#[lang = "format_unsafe_arg"]
-pub struct UnsafeArg {
-    _private: (),
-}
-
-impl UnsafeArg {
-    /// See documentation where `UnsafeArg` is required to know when it is safe to
-    /// create and use `UnsafeArg`.
-    #[inline]
-    pub const unsafe fn new() -> Self {
-        Self { _private: () }
-    }
 }
 
 /// Used by the format_args!() macro to create a fmt::Arguments object.
@@ -248,8 +216,7 @@ impl<'a> Arguments<'a> {
 
     /// Specifies nonstandard formatting parameters.
     ///
-    /// An `rt::UnsafeArg` is required because the following invariants must be held
-    /// in order for this function to be safe:
+    /// SAFETY: the following invariants must be held:
     /// 1. The `pieces` slice must be at least as long as `fmt`.
     /// 2. Every `rt::Placeholder::position` value within `fmt` must be a valid index of `args`.
     /// 3. Every `rt::Count::Param` within `fmt` must contain a valid index of `args`.
@@ -261,11 +228,10 @@ impl<'a> Arguments<'a> {
     /// const _: () = if false { panic!("a {:1}", "a") };
     /// ```
     #[inline]
-    pub fn new_v1_formatted(
+    pub unsafe fn new_v1_formatted(
         pieces: &'a [&'static str],
         args: &'a [rt::Argument<'a>],
         fmt: &'a [rt::Placeholder],
-        _unsafe_arg: rt::UnsafeArg,
     ) -> Arguments<'a> {
         Arguments { pieces, fmt: Some(fmt), args }
     }

library/coretests/tests/fmt/mod.rs

@@ -2,6 +2,21 @@ mod builders;
 mod float;
 mod num;
 
+#[test]
+fn test_lifetime() {
+    // Trigger all different forms of expansion,
+    // and check that each of them can be stored as a variable.
+    let a = format_args!("hello");
+    let a = format_args!("hello {a}");
+    let a = format_args!("hello {a:1}");
+    let a = format_args!("hello {a} {a:?}");
+    assert_eq!(a.to_string(), "hello hello hello hello hello hello hello");
+
+    // Without arguments, it should also work in consts.
+    const A: std::fmt::Arguments<'static> = format_args!("hello");
+    assert_eq!(A.to_string(), "hello");
+}
+
 #[test]
 fn test_format_flags() {
     // No residual flags left by pointer formatting

src/tools/clippy/tests/ui/author/macro_in_closure.stdout

@@ -9,28 +9,35 @@ if let StmtKind::Let(local) = stmt.kind
     && let ExprKind::Call(func, args) = e.kind
     && paths::STD_IO_STDIO__PRINT.matches_path(cx, func) // Add the path to `clippy_utils::paths` if needed
     && args.len() == 1
-    && let ExprKind::Call(func1, args1) = args[0].kind
-    && paths::CORE_FMT_RT_NEW_V1.matches_path(cx, func1) // Add the path to `clippy_utils::paths` if needed
-    && args1.len() == 2
+    && let ExprKind::Block(block1, None) = args[0].kind
+    && block1.stmts.len() == 1
+    && let StmtKind::Let(local1) = block1.stmts[0].kind
+    && let Some(init1) = local1.init
+    && let ExprKind::Array(elements) = init1.kind
+    && elements.len() == 1
+    && let ExprKind::Call(func1, args1) = elements[0].kind
+    && paths::CORE_FMT_RT_ARGUMENT_NEW_DISPLAY.matches_path(cx, func1) // Add the path to `clippy_utils::paths` if needed
+    && args1.len() == 1
     && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = args1[0].kind
-    && let ExprKind::Array(elements) = inner.kind
-    && elements.len() == 2
-    && let ExprKind::Lit(ref lit) = elements[0].kind
+    && let PatKind::Binding(BindingMode::NONE, _, name, None) = local1.pat.kind
+    && name.as_str() == "args"
+    && let Some(trailing_expr) = block1.expr
+    && let ExprKind::Call(func2, args2) = trailing_expr.kind
+    && paths::CORE_FMT_RT_NEW_V1.matches_path(cx, func2) // Add the path to `clippy_utils::paths` if needed
+    && args2.len() == 2
+    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner1) = args2[0].kind
+    && let ExprKind::Array(elements1) = inner1.kind
+    && elements1.len() == 2
+    && let ExprKind::Lit(ref lit) = elements1[0].kind
     && let LitKind::Str(s, _) = lit.node
     && s.as_str() == ""
-    && let ExprKind::Lit(ref lit1) = elements[1].kind
+    && let ExprKind::Lit(ref lit1) = elements1[1].kind
     && let LitKind::Str(s1, _) = lit1.node
     && s1.as_str() == "\n"
-    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner1) = args1[1].kind
-    && let ExprKind::Array(elements1) = inner1.kind
-    && elements1.len() == 1
-    && let ExprKind::Call(func2, args2) = elements1[0].kind
-    && paths::CORE_FMT_RT_ARGUMENT_NEW_DISPLAY.matches_path(cx, func2) // Add the path to `clippy_utils::paths` if needed
-    && args2.len() == 1
-    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner2) = args2[0].kind
+    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner2) = args2[1].kind
     && block.expr.is_none()
-    && let PatKind::Binding(BindingMode::NONE, _, name, None) = local.pat.kind
-    && name.as_str() == "print_text"
+    && let PatKind::Binding(BindingMode::NONE, _, name1, None) = local.pat.kind
+    && name1.as_str() == "print_text"
 {
     // report your lint here
 }

src/tools/clippy/tests/ui/author/macro_in_loop.stdout

@@ -19,25 +19,32 @@ if let Some(higher::ForLoop { pat: pat, arg: arg, body: body, .. }) = higher::Fo
     && let ExprKind::Call(func, args) = e1.kind
     && paths::STD_IO_STDIO__PRINT.matches_path(cx, func) // Add the path to `clippy_utils::paths` if needed
     && args.len() == 1
-    && let ExprKind::Call(func1, args1) = args[0].kind
-    && paths::CORE_FMT_RT_NEW_V1.matches_path(cx, func1) // Add the path to `clippy_utils::paths` if needed
-    && args1.len() == 2
+    && let ExprKind::Block(block2, None) = args[0].kind
+    && block2.stmts.len() == 1
+    && let StmtKind::Let(local) = block2.stmts[0].kind
+    && let Some(init) = local.init
+    && let ExprKind::Array(elements) = init.kind
+    && elements.len() == 1
+    && let ExprKind::Call(func1, args1) = elements[0].kind
+    && paths::CORE_FMT_RT_ARGUMENT_NEW_DISPLAY.matches_path(cx, func1) // Add the path to `clippy_utils::paths` if needed
+    && args1.len() == 1
     && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = args1[0].kind
-    && let ExprKind::Array(elements) = inner.kind
-    && elements.len() == 2
-    && let ExprKind::Lit(ref lit2) = elements[0].kind
+    && let PatKind::Binding(BindingMode::NONE, _, name1, None) = local.pat.kind
+    && name1.as_str() == "args"
+    && let Some(trailing_expr) = block2.expr
+    && let ExprKind::Call(func2, args2) = trailing_expr.kind
+    && paths::CORE_FMT_RT_NEW_V1.matches_path(cx, func2) // Add the path to `clippy_utils::paths` if needed
+    && args2.len() == 2
+    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner1) = args2[0].kind
+    && let ExprKind::Array(elements1) = inner1.kind
+    && elements1.len() == 2
+    && let ExprKind::Lit(ref lit2) = elements1[0].kind
     && let LitKind::Str(s, _) = lit2.node
     && s.as_str() == ""
-    && let ExprKind::Lit(ref lit3) = elements[1].kind
+    && let ExprKind::Lit(ref lit3) = elements1[1].kind
     && let LitKind::Str(s1, _) = lit3.node
     && s1.as_str() == "\n"
-    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner1) = args1[1].kind
-    && let ExprKind::Array(elements1) = inner1.kind
-    && elements1.len() == 1
-    && let ExprKind::Call(func2, args2) = elements1[0].kind
-    && paths::CORE_FMT_RT_ARGUMENT_NEW_DISPLAY.matches_path(cx, func2) // Add the path to `clippy_utils::paths` if needed
-    && args2.len() == 1
-    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner2) = args2[0].kind
+    && let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner2) = args2[1].kind
     && block1.expr.is_none()
     && block.expr.is_none()
 {

src/tools/clippy/tests/ui/manual_inspect.fixed

@@ -154,7 +154,6 @@ fn main() {
     });
 
     let _ = [0]
-        //~^ suspicious_map
         .into_iter()
         .inspect(|&x| {
             //~^ manual_inspect

src/tools/clippy/tests/ui/manual_inspect.rs

@@ -165,7 +165,6 @@ fn main() {
     });
 
     let _ = [0]
-        //~^ suspicious_map
         .into_iter()
         .map(|x| {
             //~^ manual_inspect

src/tools/clippy/tests/ui/manual_inspect.stderr

@@ -157,25 +157,8 @@ LL |
 LL ~         println!("{}", x);
    |
 
-error: this call to `map()` won't have an effect on the call to `count()`
-  --> tests/ui/manual_inspect.rs:167:13
-   |
-LL |       let _ = [0]
-   |  _____________^
-LL | |
-LL | |         .into_iter()
-LL | |         .map(|x| {
-...  |
-LL | |         })
-LL | |         .count();
-   | |________________^
-   |
-   = help: make sure you did not confuse `map` with `filter`, `for_each` or `inspect`
-   = note: `-D clippy::suspicious-map` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(clippy::suspicious_map)]`
-
 error: using `map` over `inspect`
-  --> tests/ui/manual_inspect.rs:170:10
+  --> tests/ui/manual_inspect.rs:169:10
    |
 LL |         .map(|x| {
    |          ^^^
@@ -188,7 +171,7 @@ LL ~             println!("{}", x);
    |
 
 error: using `map` over `inspect`
-  --> tests/ui/manual_inspect.rs:203:30
+  --> tests/ui/manual_inspect.rs:202:30
    |
 LL |     if let Some(x) = Some(1).map(|x| { println!("{x}");
    |                              ^^^
@@ -200,5 +183,5 @@ LL |         // Do not collapse code into this comment
 LL ~          }) {
    |
 
-error: aborting due to 14 previous errors
+error: aborting due to 13 previous errors
 

src/tools/tidy/src/issues.txt

@@ -305,7 +305,6 @@ ui/borrowck/issue-104639-lifetime-order.rs
 ui/borrowck/issue-10876.rs
 ui/borrowck/issue-109271-pass-self-into-closure.rs
 ui/borrowck/issue-111554.rs
-ui/borrowck/issue-114374-invalid-help-fmt-args.rs
 ui/borrowck/issue-11493.rs
 ui/borrowck/issue-115259-suggest-iter-mut.rs
 ui/borrowck/issue-119915-bad-clone-suggestion.rs

tests/mir-opt/sroa/lifetimes.foo.ScalarReplacementOfAggregates.diff

@@ -11,28 +11,29 @@
       let _9: ();
       let _10: ();
       let mut _11: std::fmt::Arguments<'_>;
-      let mut _12: &[&str; 3];
-      let _13: &[&str; 3];
-      let _14: [&str; 3];
-      let mut _15: &[core::fmt::rt::Argument<'_>; 2];
-      let _16: &[core::fmt::rt::Argument<'_>; 2];
-      let _17: [core::fmt::rt::Argument<'_>; 2];
+      let mut _13: &std::boxed::Box<dyn std::fmt::Display>;
+      let mut _14: &u32;
+      let mut _16: core::fmt::rt::Argument<'_>;
+      let mut _17: &std::boxed::Box<dyn std::fmt::Display>;
       let mut _18: core::fmt::rt::Argument<'_>;
-      let mut _19: &std::boxed::Box<dyn std::fmt::Display>;
-      let _20: &std::boxed::Box<dyn std::fmt::Display>;
-      let mut _21: core::fmt::rt::Argument<'_>;
-      let mut _22: &u32;
-      let _23: &u32;
-      let mut _25: bool;
-      let mut _26: isize;
-      let mut _27: isize;
-      let mut _28: isize;
-+     let _29: std::result::Result<std::boxed::Box<dyn std::fmt::Display>, <T as Err>::Err>;
-+     let _30: u32;
+      let mut _19: &u32;
+      let mut _20: &[&str; 3];
+      let _21: &[&str; 3];
+      let _22: [&str; 3];
+      let mut _23: &[core::fmt::rt::Argument<'_>; 2];
+      let _24: &[core::fmt::rt::Argument<'_>; 2];
+      let mut _26: &std::boxed::Box<dyn std::fmt::Display>;
+      let mut _27: &u32;
+      let mut _28: bool;
+      let mut _29: isize;
+      let mut _30: isize;
+      let mut _31: isize;
++     let _32: std::result::Result<std::boxed::Box<dyn std::fmt::Display>, <T as Err>::Err>;
++     let _33: u32;
       scope 1 {
 -         debug foo => _1;
-+         debug ((foo: Foo<T>).0: std::result::Result<std::boxed::Box<dyn std::fmt::Display>, <T as Err>::Err>) => _29;
-+         debug ((foo: Foo<T>).1: u32) => _30;
++         debug ((foo: Foo<T>).0: std::result::Result<std::boxed::Box<dyn std::fmt::Display>, <T as Err>::Err>) => _32;
++         debug ((foo: Foo<T>).1: u32) => _33;
           let _5: std::result::Result<std::boxed::Box<dyn std::fmt::Display>, <T as Err>::Err>;
           scope 2 {
               debug x => _5;
@@ -42,17 +43,29 @@
                   scope 4 {
                       debug x => _8;
                       let _8: std::boxed::Box<dyn std::fmt::Display>;
-                      let mut _24: &[&str; 3];
+                      let _12: (&std::boxed::Box<dyn std::fmt::Display>, &u32);
++                     let _34: &std::boxed::Box<dyn std::fmt::Display>;
++                     let _35: &u32;
+                      scope 5 {
+-                         debug args => _12;
++                         debug ((args: (&Box<dyn std::fmt::Display>, &u32)).0: &std::boxed::Box<dyn std::fmt::Display>) => _34;
++                         debug ((args: (&Box<dyn std::fmt::Display>, &u32)).1: &u32) => _35;
+                          let _15: [core::fmt::rt::Argument<'_>; 2];
+                          scope 6 {
+                              debug args => _15;
+                              let mut _25: &[&str; 3];
+                          }
+                      }
                   }
               }
           }
       }
 
       bb0: {
-          _25 = const false;
+          _28 = const false;
 -         StorageLive(_1);
-+         StorageLive(_29);
-+         StorageLive(_30);
++         StorageLive(_32);
++         StorageLive(_33);
 +         nop;
           StorageLive(_2);
           StorageLive(_3);
@@ -66,77 +79,93 @@
           _2 = Result::<Box<dyn std::fmt::Display>, <T as Err>::Err>::Ok(move _3);
           StorageDead(_3);
 -         _1 = Foo::<T> { x: move _2, y: const 7_u32 };
-+         _29 = move _2;
-+         _30 = const 7_u32;
++         _32 = move _2;
++         _33 = const 7_u32;
 +         nop;
           StorageDead(_2);
           StorageLive(_5);
-          _25 = const true;
+          _28 = const true;
 -         _5 = move (_1.0: std::result::Result<std::boxed::Box<dyn std::fmt::Display>, <T as Err>::Err>);
-+         _5 = move _29;
++         _5 = move _32;
           StorageLive(_6);
 -         _6 = copy (_1.1: u32);
-+         _6 = copy _30;
++         _6 = copy _33;
           _7 = discriminant(_5);
           switchInt(move _7) -> [0: bb2, otherwise: bb7];
       }
 
       bb2: {
           StorageLive(_8);
-          _25 = const false;
+          _28 = const false;
           _8 = move ((_5 as Ok).0: std::boxed::Box<dyn std::fmt::Display>);
           StorageLive(_9);
           StorageLive(_10);
           StorageLive(_11);
-          StorageLive(_12);
+-         StorageLive(_12);
++         StorageLive(_34);
++         StorageLive(_35);
++         nop;
           StorageLive(_13);
-          _24 = const foo::<T>::promoted[0];
-          _13 = &(*_24);
-          _12 = &(*_13);
+          _13 = &_8;
+          StorageLive(_14);
+          _14 = &_6;
+-         _12 = (move _13, move _14);
++         _34 = move _13;
++         _35 = move _14;
++         nop;
+          StorageDead(_14);
+          StorageDead(_13);
           StorageLive(_15);
           StorageLive(_16);
           StorageLive(_17);
-          StorageLive(_18);
-          StorageLive(_19);
-          StorageLive(_20);
-          _20 = &_8;
-          _19 = &(*_20);
-          _18 = core::fmt::rt::Argument::<'_>::new_display::<Box<dyn std::fmt::Display>>(move _19) -> [return: bb3, unwind unreachable];
+-         _26 = deref_copy (_12.0: &std::boxed::Box<dyn std::fmt::Display>);
++         _26 = deref_copy _34;
+          _17 = &(*_26);
+          _16 = core::fmt::rt::Argument::<'_>::new_display::<Box<dyn std::fmt::Display>>(move _17) -> [return: bb3, unwind unreachable];
       }
 
       bb3: {
-          StorageDead(_19);
-          StorageLive(_21);
-          StorageLive(_22);
-          StorageLive(_23);
-          _23 = &_6;
-          _22 = &(*_23);
-          _21 = core::fmt::rt::Argument::<'_>::new_display::<u32>(move _22) -> [return: bb4, unwind unreachable];
+          StorageDead(_17);
+          StorageLive(_18);
+          StorageLive(_19);
+-         _27 = deref_copy (_12.1: &u32);
++         _27 = deref_copy _35;
+          _19 = &(*_27);
+          _18 = core::fmt::rt::Argument::<'_>::new_display::<u32>(move _19) -> [return: bb4, unwind unreachable];
       }
 
       bb4: {
-          StorageDead(_22);
-          _17 = [move _18, move _21];
-          StorageDead(_21);
+          StorageDead(_19);
+          _15 = [move _16, move _18];
           StorageDead(_18);
-          _16 = &_17;
-          _15 = &(*_16);
-          _11 = core::fmt::rt::<impl Arguments<'_>>::new_v1::<3, 2>(move _12, move _15) -> [return: bb5, unwind unreachable];
+          StorageDead(_16);
+          StorageLive(_20);
+          StorageLive(_21);
+          _25 = const foo::<T>::promoted[0];
+          _21 = &(*_25);
+          _20 = &(*_21);
+          StorageLive(_23);
+          StorageLive(_24);
+          _24 = &_15;
+          _23 = &(*_24);
+          _11 = core::fmt::rt::<impl Arguments<'_>>::new_v1::<3, 2>(move _20, move _23) -> [return: bb5, unwind unreachable];
       }
 
       bb5: {
-          StorageDead(_15);
-          StorageDead(_12);
+          StorageDead(_24);
+          StorageDead(_23);
+          StorageDead(_21);
+          StorageDead(_20);
           _10 = _eprint(move _11) -> [return: bb6, unwind unreachable];
       }
 
       bb6: {
           StorageDead(_11);
-          StorageDead(_23);
-          StorageDead(_20);
-          StorageDead(_17);
-          StorageDead(_16);
-          StorageDead(_13);
+          StorageDead(_15);
+-         StorageDead(_12);
++         StorageDead(_34);
++         StorageDead(_35);
++         nop;
           StorageDead(_10);
           _9 = const ();
           StorageDead(_9);
@@ -156,22 +185,22 @@
 
       bb9: {
           StorageDead(_6);
-          _26 = discriminant(_5);
-          switchInt(move _26) -> [0: bb11, otherwise: bb13];
+          _29 = discriminant(_5);
+          switchInt(move _29) -> [0: bb11, otherwise: bb13];
       }
 
       bb10: {
-          _25 = const false;
+          _28 = const false;
           StorageDead(_5);
 -         StorageDead(_1);
-+         StorageDead(_29);
-+         StorageDead(_30);
++         StorageDead(_32);
++         StorageDead(_33);
 +         nop;
           return;
       }
 
       bb11: {
-          switchInt(copy _25) -> [0: bb10, otherwise: bb12];
+          switchInt(copy _28) -> [0: bb10, otherwise: bb12];
       }
 
       bb12: {

tests/ui/borrowck/clone-on-ref.stderr

@@ -30,7 +30,7 @@ LL |     drop(x);
    |          ^ move out of `x` occurs here
 LL |
 LL |     println!("{b}");
-   |               --- borrow later used here
+   |                - borrow later used here
    |
 help: if `T` implemented `Clone`, you could clone the value
   --> $DIR/clone-on-ref.rs:11:8
@@ -57,7 +57,7 @@ LL |     drop(x);
    |          ^ move out of `x` occurs here
 LL |
 LL |     println!("{b:?}");
-   |               ----- borrow later used here
+   |                - borrow later used here
    |
 note: if `A` implemented `Clone`, you could clone the value
   --> $DIR/clone-on-ref.rs:19:1

tests/ui/consts/recursive-const-in-impl.stderr

@@ -1,11 +1,12 @@
 error: queries overflow the depth limit!
-  --> $DIR/recursive-const-in-impl.rs:11:14
+  --> $DIR/recursive-const-in-impl.rs:11:20
    |
 LL |     println!("{}", Thing::<i32>::X);
-   |              ^^^^
+   |                    ^^^^^^^^^^^^^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "14"]` attribute to your crate (`recursive_const_in_impl`)
    = note: query depth increased by 9 when simplifying constant for the type system `main::promoted[1]`
+   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 

tests/ui/impl-trait/precise-capturing/foreign-2021.stderr

@@ -8,7 +8,7 @@ LL |     x.push(0);
    |     ^^^^^^^^^ mutable borrow occurs here
 ...
 LL |     println!("{h}");
-   |               --- immutable borrow later used here
+   |                - immutable borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/foreign-2021.rs:7:13

tests/ui/impl-trait/precise-capturing/migration-note.stderr

@@ -23,7 +23,7 @@ LL |     x.push(1);
    |     ^^^^^^^^^ mutable borrow occurs here
 ...
 LL |     println!("{a}");
-   |               --- immutable borrow later used here
+   |                - immutable borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/migration-note.rs:16:13
@@ -99,7 +99,7 @@ LL |     x.push(1);
    |     ^ second mutable borrow occurs here
 ...
 LL |     println!("{a}");
-   |               --- first borrow later used here
+   |                - first borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/migration-note.rs:63:13
@@ -175,7 +175,7 @@ LL |     s.f = 1;
    |     ^^^^^^^ `s.f` is assigned to here but it was already borrowed
 ...
 LL |     println!("{a}");
-   |               --- borrow later used here
+   |                - borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/migration-note.rs:112:13
@@ -197,7 +197,7 @@ LL |     s.f = 1;
    |     ^^^^^^^ `s.f` is assigned to here but it was already borrowed
 ...
 LL |     println!("{a}");
-   |               --- borrow later used here
+   |                - borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/migration-note.rs:128:13
@@ -219,7 +219,7 @@ LL |     s.f;
    |     ^^^ use of borrowed `s.f`
 ...
 LL |     println!("{a}");
-   |               --- borrow later used here
+   |                - borrow later used here
    |
 note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
   --> $DIR/migration-note.rs:140:13

tests/ui/lifetimes/temporary-lifetime-extension-tuple-ctor.stderr

@@ -6,7 +6,7 @@ LL |     let g = some(&temp());
    |                   |
    |                   creates a temporary value which is freed while still in use
 LL |     println!("{a:?} {b:?} {c:?} {d:?} {e:?} {f:?} {g:?}");
-   |                                                   ----- borrow later used here
+   |                                                    - borrow later used here
    |
 help: consider using a `let` binding to create a longer lived value
    |

tests/ui/macros/format-args-temporaries-in-write.stderr

@@ -13,11 +13,6 @@ LL |     };
    |     -- ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `MutexGuard`
    |     |
    |     `mutex` dropped here while still borrowed
-   |
-help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
-   |
-LL |         write!(Out, "{}", mutex.lock()); /* no semicolon */
-   |                                        +
 
 error[E0597]: `mutex` does not live long enough
   --> $DIR/format-args-temporaries-in-write.rs:47:29
@@ -34,11 +29,6 @@ LL |     };
    |     -- ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `MutexGuard`
    |     |
    |     `mutex` dropped here while still borrowed
-   |
-help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
-   |
-LL |         writeln!(Out, "{}", mutex.lock()); /* no semicolon */
-   |                                          +
 
 error: aborting due to 2 previous errors
 

tests/ui/sized/unsized-binding.rs

@@ -1,5 +1,5 @@
 fn main() {
     let x = *""; //~ ERROR E0277
-    println!("{}", x);
-    println!("{}", x);
+    drop(x);
+    drop(x);
 }

tests/ui/suggestions/issue-97760.stderr

@@ -1,8 +1,8 @@
 error[E0277]: `<impl IntoIterator as IntoIterator>::Item` doesn't implement `std::fmt::Display`
-  --> $DIR/issue-97760.rs:4:19
+  --> $DIR/issue-97760.rs:4:20
    |
 LL |         println!("{x}");
-   |                   ^^^ `<impl IntoIterator as IntoIterator>::Item` cannot be formatted with the default formatter
+   |                    ^ `<impl IntoIterator as IntoIterator>::Item` cannot be formatted with the default formatter
    |
    = help: the trait `std::fmt::Display` is not implemented for `<impl IntoIterator as IntoIterator>::Item`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead

tests/ui/unpretty/exhaustive.hir.stdout

@@ -405,8 +405,10 @@ mod expressions {
     fn expr_format_args() {
         let expr;
         format_arguments::new_const(&[]);
-        format_arguments::new_v1(&[""],
-            &[format_argument::new_display(&expr)]);
+        {
+            super let args = [format_argument::new_display(&expr)];
+            format_arguments::new_v1(&[""], &args)
+        };
     }
 }
 mod items {

tests/ui/unpretty/flattened-format-args.stdout

@@ -10,7 +10,9 @@ fn main() {
     let x = 1;
     // Should flatten to println!("a 123 b {x} xyz\n"):
     {
-        ::std::io::_print(format_arguments::new_v1(&["a 123 b ", " xyz\n"],
-                &[format_argument::new_display(&x)]));
+        ::std::io::_print({
+                super let args = [format_argument::new_display(&x)];
+                format_arguments::new_v1(&["a 123 b ", " xyz\n"], &args)
+            });
     };
 }