From a0d6d2ce60514b1af4b031fc843545f031a40437 Mon Sep 17 00:00:00 2001 From: dianne Date: Sun, 7 Jun 2026 02:29:59 -0700 Subject: [PATCH 1/2] adjust a diagnostic test for `dbg!` Two things: Since `dbg!` is changing, this removes parts of the file that assumed it expands a certain way. The removed tests will no longer get the "consider borrowing" messages going forward, but I think that's fine; it's unlikely that someone would have hand-written them and the suggestion could easily be wrong in the general case. If we want a more general help message to suggest borrowing in those cases, I think it should be designed as such from the ground up, not targeting `dbg!`. From what I can tell, this test file was intended to be for the "consider borrowing" help messages on diagnostics for `dbg!`. To make it harder to accidentally mess with those messages, I've added checks for them and some comments to clarify intent. --- tests/ui/borrowck/dbg-issue-120327.rs | 53 +++++++--------------- tests/ui/borrowck/dbg-issue-120327.stderr | 54 ++++++++++------------- 2 files changed, 39 insertions(+), 68 deletions(-) diff --git a/tests/ui/borrowck/dbg-issue-120327.rs b/tests/ui/borrowck/dbg-issue-120327.rs index 2de43f634877a..45605acc34334 100644 --- a/tests/ui/borrowck/dbg-issue-120327.rs +++ b/tests/ui/borrowck/dbg-issue-120327.rs @@ -1,67 +1,44 @@ +//! Diagnostic test for : suggest borrowing +//! variables passed to `dbg!` that are later used. +//@ dont-require-annotations: HELP + fn s() -> String { let a = String::new(); - dbg!(a); + dbg!(a); //~ HELP consider borrowing instead of transferring ownership return a; //~ ERROR use of moved value: } fn m() -> String { let a = String::new(); - dbg!(1, 2, a, 1, 2); + dbg!(1, 2, a, 1, 2); //~ HELP consider borrowing instead of transferring ownership return a; //~ ERROR use of moved value: } fn t(a: String) -> String { let b: String = "".to_string(); - dbg!(a, b); + dbg!(a, b); //~ HELP consider borrowing instead of transferring ownership return b; //~ ERROR use of moved value: } fn x(a: String) -> String { let b: String = "".to_string(); - dbg!(a, b); + dbg!(a, b); //~ HELP consider borrowing instead of transferring ownership return a; //~ ERROR use of moved value: } -macro_rules! my_dbg { - () => { - eprintln!("[{}:{}:{}]", file!(), line!(), column!()) - }; - ($val:expr $(,)?) => { - match $val { - tmp => { - eprintln!("[{}:{}:{}] {} = {:#?}", - file!(), line!(), column!(), stringify!($val), &tmp); - tmp - } - } - }; - ($($val:expr),+ $(,)?) => { - ($(my_dbg!($val)),+,) - }; -} - -fn test_my_dbg() -> String { - let b: String = "".to_string(); - my_dbg!(b, 1); - return b; //~ ERROR use of moved value: -} - -fn test_not_macro() -> String { - let a = String::new(); - let _b = match a { - tmp => { - eprintln!("dbg: {}", tmp); - tmp - } - }; - return a; //~ ERROR use of moved value: +fn two_of_them(a: String) -> String { + dbg!(a, a); //~ ERROR use of moved value + //~| HELP consider borrowing instead of transferring ownership + //~| HELP consider borrowing instead of transferring ownership + return a; //~ ERROR use of moved value } fn get_expr(_s: String) {} +// The suggestion is purely syntactic; applying it here will result in a type error. fn test() { let a: String = "".to_string(); - let _res = get_expr(dbg!(a)); + let _res = get_expr(dbg!(a)); //~ HELP consider borrowing instead of transferring ownership let _l = a.len(); //~ ERROR borrow of moved value } diff --git a/tests/ui/borrowck/dbg-issue-120327.stderr b/tests/ui/borrowck/dbg-issue-120327.stderr index efacc0c3f1341..b23c7ba5ebbbc 100644 --- a/tests/ui/borrowck/dbg-issue-120327.stderr +++ b/tests/ui/borrowck/dbg-issue-120327.stderr @@ -1,5 +1,5 @@ error[E0382]: use of moved value: `a` - --> $DIR/dbg-issue-120327.rs:4:12 + --> $DIR/dbg-issue-120327.rs:8:12 | LL | let a = String::new(); | - move occurs because `a` has type `String`, which does not implement the `Copy` trait @@ -14,7 +14,7 @@ LL | dbg!(&a); | + error[E0382]: use of moved value: `a` - --> $DIR/dbg-issue-120327.rs:10:12 + --> $DIR/dbg-issue-120327.rs:14:12 | LL | let a = String::new(); | - move occurs because `a` has type `String`, which does not implement the `Copy` trait @@ -29,7 +29,7 @@ LL | dbg!(1, 2, &a, 1, 2); | + error[E0382]: use of moved value: `b` - --> $DIR/dbg-issue-120327.rs:16:12 + --> $DIR/dbg-issue-120327.rs:20:12 | LL | let b: String = "".to_string(); | - move occurs because `b` has type `String`, which does not implement the `Copy` trait @@ -44,7 +44,7 @@ LL | dbg!(a, &b); | + error[E0382]: use of moved value: `a` - --> $DIR/dbg-issue-120327.rs:22:12 + --> $DIR/dbg-issue-120327.rs:26:12 | LL | fn x(a: String) -> String { | - move occurs because `a` has type `String`, which does not implement the `Copy` trait @@ -59,46 +59,40 @@ help: consider borrowing instead of transferring ownership LL | dbg!(&a, b); | + -error[E0382]: use of moved value: `b` - --> $DIR/dbg-issue-120327.rs:46:12 +error[E0382]: use of moved value: `a` + --> $DIR/dbg-issue-120327.rs:33:12 | -LL | tmp => { - | --- value moved here +LL | fn two_of_them(a: String) -> String { + | - move occurs because `a` has type `String`, which does not implement the `Copy` trait +LL | dbg!(a, a); + | ---------- value moved here ... -LL | let b: String = "".to_string(); - | - move occurs because `b` has type `String`, which does not implement the `Copy` trait -LL | my_dbg!(b, 1); -LL | return b; +LL | return a; | ^ value used here after move | help: consider borrowing instead of transferring ownership | -LL | my_dbg!(&b, 1); +LL | dbg!(a, &a); | + -help: borrow this binding in the pattern to avoid moving the value - | -LL | ref tmp => { - | +++ error[E0382]: use of moved value: `a` - --> $DIR/dbg-issue-120327.rs:57:12 + --> $DIR/dbg-issue-120327.rs:30:5 | -LL | let a = String::new(); - | - move occurs because `a` has type `String`, which does not implement the `Copy` trait -LL | let _b = match a { -LL | tmp => { - | --- value moved here -... -LL | return a; - | ^ value used here after move +LL | fn two_of_them(a: String) -> String { + | - move occurs because `a` has type `String`, which does not implement the `Copy` trait +LL | dbg!(a, a); + | ^^^^^^^^^^ + | | + | value moved here + | value used here after move | -help: borrow this binding in the pattern to avoid moving the value +help: consider borrowing instead of transferring ownership | -LL | ref tmp => { - | +++ +LL | dbg!(a, &a); + | + error[E0382]: borrow of moved value: `a` - --> $DIR/dbg-issue-120327.rs:65:14 + --> $DIR/dbg-issue-120327.rs:42:14 | LL | let a: String = "".to_string(); | - move occurs because `a` has type `String`, which does not implement the `Copy` trait From 64b6b6b74af42aaf6a16b46f4a2e5dbe89a7f338 Mon Sep 17 00:00:00 2001 From: dianne Date: Tue, 28 Apr 2026 03:44:58 -0700 Subject: [PATCH 2/2] prevent `dbg!` from tearing using `super let` --- .../src/diagnostics/conflict_errors.rs | 29 +++--- compiler/rustc_span/src/symbol.rs | 1 + library/std/src/lib.rs | 4 +- library/std/src/macros.rs | 79 +++++++++++---- .../clippy/clippy_lints/src/dbg_macro.rs | 98 ++++++++++--------- src/tools/clippy/clippy_utils/src/sym.rs | 1 - .../dangling_primitive.stderr | 2 +- .../return_pointer_on_unwind.stderr | 2 +- tests/ui/borrowck/dbg-issue-120327.stderr | 61 ++++++++---- tests/ui/liveness/liveness-upvars.rs | 2 +- tests/ui/liveness/liveness-upvars.stderr | 10 +- .../mismatched-types-issue-126222.fixed | 4 +- .../mismatched-types-issue-126222.stderr | 38 ++++--- .../dbg-macro-move-semantics.stderr | 14 ++- 14 files changed, 231 insertions(+), 114 deletions(-) diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs index f1a22fd6af982..f9edf556e771c 100644 --- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs @@ -595,31 +595,38 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> { }); let Some(var_info) = var_info else { return }; let arg_name = var_info.name; - struct MatchArgFinder { - expr_span: Span, - match_arg_span: Option, + struct DbgArgFinder<'tcx> { + tcx: TyCtxt<'tcx>, + move_span: Span, arg_name: Symbol, + dbg_arg_span: Option = None, } - impl Visitor<'_> for MatchArgFinder { + impl Visitor<'_> for DbgArgFinder<'_> { fn visit_expr(&mut self, e: &hir::Expr<'_>) { - // dbg! is expanded into a match pattern, we need to find the right argument span - if let hir::ExprKind::Match(expr, ..) = &e.kind + // dbg! is expanded into assignments, we need to find the right argument span + if let hir::ExprKind::Assign(_, arg, _) = &e.kind && let hir::ExprKind::Path(hir::QPath::Resolved( _, path @ Path { segments: [seg], .. }, - )) = &expr.kind + )) = &arg.kind && seg.ident.name == self.arg_name - && self.expr_span.source_callsite().contains(expr.span) + && self.move_span.source_equal(arg.span) + && e.span.macro_backtrace().any(|expn| { + expn.macro_def_id.is_some_and(|macro_def_id| { + self.tcx.is_diagnostic_item(sym::dbg_macro, macro_def_id) + }) + }) { - self.match_arg_span = Some(path.span); + self.dbg_arg_span = Some(path.span); + return; } hir::intravisit::walk_expr(self, e); } } - let mut finder = MatchArgFinder { expr_span: move_span, match_arg_span: None, arg_name }; + let mut finder = DbgArgFinder { tcx: self.infcx.tcx, move_span, arg_name, .. }; finder.visit_expr(body); - if let Some(macro_arg_span) = finder.match_arg_span { + if let Some(macro_arg_span) = finder.dbg_arg_span { err.span_suggestion_verbose( macro_arg_span.shrink_to_lo(), "consider borrowing instead of transferring ownership", diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 9313e869278db..0f0067e89592a 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -753,6 +753,7 @@ symbols! { custom_mir, custom_test_frameworks, d32, + dbg_macro, dead_code, dead_code_pub_in_binary, dealloc, diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 09d81f11e0a45..f29886ad7483d 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -496,7 +496,9 @@ extern crate std as realstd; // The standard macros that are not built-in to the compiler. #[macro_use] -mod macros; +#[doc(hidden)] +#[unstable(feature = "std_internals", issue = "none")] +pub mod macros; // The runtime entry point and a few unstable public functions used by the // compiler diff --git a/library/std/src/macros.rs b/library/std/src/macros.rs index 8bcf870e9aeb4..8f45eddb34d08 100644 --- a/library/std/src/macros.rs +++ b/library/std/src/macros.rs @@ -350,6 +350,7 @@ macro_rules! eprintln { /// [`debug!`]: https://docs.rs/log/*/log/macro.debug.html /// [`log`]: https://crates.io/crates/log #[macro_export] +#[allow_internal_unstable(std_internals)] #[cfg_attr(not(test), rustc_diagnostic_item = "dbg_macro")] #[stable(feature = "dbg_macro", since = "1.32.0")] macro_rules! dbg { @@ -360,29 +361,69 @@ macro_rules! dbg { () => { $crate::eprintln!("[{}:{}:{}]", $crate::file!(), $crate::line!(), $crate::column!()) }; - ($val:expr $(,)?) => { - // Use of `match` here is intentional because it affects the lifetimes - // of temporaries - https://stackoverflow.com/a/48732525/1063961 - match $val { - tmp => { - $crate::eprintln!("[{}:{}:{}] {} = {:#?}", - $crate::file!(), - $crate::line!(), - $crate::column!(), - $crate::stringify!($val), - // The `&T: Debug` check happens here (not in the format literal desugaring) - // to avoid format literal related messages and suggestions. - &&tmp as &dyn $crate::fmt::Debug, - ); - tmp - } - } - }; ($($val:expr),+ $(,)?) => { - ($($crate::dbg!($val)),+,) + $crate::macros::dbg_internal!(() () ($($val),+)) }; } +/// Internal macro that processes a list of expressions, binds their results, calls `eprint!` with +/// the collected information, and returns all the evaluated expressions in a tuple. +/// +/// E.g. `dbg_internal!(() () (1, 2))` expands into +/// ```rust, ignore +/// { +/// let tmp_1; +/// let tmp_2; +/// super let _ = (tmp_1 = 1); +/// super let _ = (tmp_2 = 2); +/// eprint!("...", &tmp_1, &tmp_2, /* some other arguments */); +/// (tmp_1, tmp_2) +/// } +/// ``` +/// +/// This is necessary so that `dbg!` outputs don't get torn, see #136703. +/// `super let` is used to avoid creating a temporary scope around `dbg!`'s arguments. Nested +/// `match` is insufficient because match arms introduce temporary scopes (#153850) and using a +/// single match on a tuple containing all the arguments is insufficient because of an imprecision +/// in the borrow-checker (see #155902). +#[doc(hidden)] +#[allow_internal_unstable(std_internals, super_let)] +#[rustc_macro_transparency = "semiopaque"] +#[unstable(feature = "std_internals", issue = "none")] +pub macro dbg_internal { + (($($piece:literal),+) ($($processed:expr => $bound:ident),+) ()) => {{ + $(let $bound);+; + $(super let _ = ($bound = $processed));+; + $crate::eprint!( + $crate::concat!($($piece),+), + $( + $crate::stringify!($processed), + // The `&T: Debug` check happens here (not in the format literal desugaring) + // to avoid format literal related messages and suggestions. + &&$bound as &dyn $crate::fmt::Debug + ),+, + // The location returned here is that of the macro invocation, so + // it will be the same for all expressions. Thus, label these + // arguments so that they can be reused in every piece of the + // formatting template. + file=$crate::file!(), + line=$crate::line!(), + column=$crate::column!() + ); + // Comma separate the variables only when necessary so that this will + // not yield a tuple for a single expression, but rather just parenthesize + // the expression. + ($($bound),+) + }}, + (($($piece:literal),*) ($($processed:expr => $bound:ident),*) ($val:expr $(,$rest:expr)*)) => { + $crate::macros::dbg_internal!( + ($($piece,)* "[{file}:{line}:{column}] {} = {:#?}\n") + ($($processed => $bound,)* $val => tmp) + ($($rest),*) + ) + }, +} + #[doc(hidden)] #[macro_export] #[allow_internal_unstable(hash_map_internals)] diff --git a/src/tools/clippy/clippy_lints/src/dbg_macro.rs b/src/tools/clippy/clippy_lints/src/dbg_macro.rs index adc1c0a6c577c..f6f6316763357 100644 --- a/src/tools/clippy/clippy_lints/src/dbg_macro.rs +++ b/src/tools/clippy/clippy_lints/src/dbg_macro.rs @@ -75,51 +75,61 @@ impl LateLintPass<'_> for DbgMacro { "the `dbg!` macro is intended as a debugging tool", |diag| { let mut applicability = Applicability::MachineApplicable; - let (sugg_span, suggestion) = - match is_async_move_desugar(expr).unwrap_or(expr).peel_drop_temps().kind { - // dbg!() - ExprKind::Block(..) => { - // If the `dbg!` macro is a "free" statement and not contained within other expressions, - // remove the whole statement. - if let Node::Stmt(_) = cx.tcx.parent_hir_node(expr.hir_id) - && let Some(semi_span) = - cx.sess().source_map().mac_call_stmt_semi_span(macro_call.span) - { - (macro_call.span.to(semi_span), String::new()) - } else { - (macro_call.span, String::from("()")) - } - }, - // dbg!(1) - ExprKind::Match(val, ..) => ( - macro_call.span, + let dbg_expn = is_async_move_desugar(expr).unwrap_or(expr).peel_drop_temps(); + // `dbg!` always expands to a block. If it was given arguments, it assigns names to them + // using `super let _ = (tmp = $arg);` statements. + let ExprKind::Block(block, _) = dbg_expn.kind else { + unreachable!() + }; + let args: Vec<_> = block + .stmts + .iter() + .filter_map(|stmt| { + if let StmtKind::Let(LetStmt { + super_: Some(_), + init: Some(init), + .. + }) = stmt.kind + && let ExprKind::Assign(_, arg, _) = init.kind + { + Some(arg) + } else { + None + } + }) + .collect(); + + let (sugg_span, suggestion) = match args.as_slice() { + // dbg!() + [] => { + // If the `dbg!` macro is a "free" statement and not contained within other expressions, + // remove the whole statement. + if let Node::Stmt(_) = cx.tcx.parent_hir_node(expr.hir_id) + && let Some(semi_span) = cx.sess().source_map().mac_call_stmt_semi_span(macro_call.span) + { + (macro_call.span.to(semi_span), String::new()) + } else { + (macro_call.span, String::from("()")) + } + }, + // dbg!(1) => 1 + [val] => { + let suggestion = snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability) - .to_string(), - ), - // dbg!(2, 3) - ExprKind::Tup( - [ - Expr { - kind: ExprKind::Match(first, ..), - .. - }, - .., - Expr { - kind: ExprKind::Match(last, ..), - .. - }, - ], - ) => { - let snippet = snippet_with_applicability( - cx, - first.span.source_callsite().to(last.span.source_callsite()), - "..", - &mut applicability, - ); - (macro_call.span, format!("({snippet})")) - }, - _ => unreachable!(), - }; + .to_string(); + (macro_call.span, suggestion) + }, + // dbg!(2, 3) => (2, 3) + [first, .., last] => { + let snippet = snippet_with_applicability( + cx, + first.span.source_callsite().to(last.span.source_callsite()), + "..", + &mut applicability, + ); + (macro_call.span, format!("({snippet})")) + }, + }; diag.span_suggestion( sugg_span, diff --git a/src/tools/clippy/clippy_utils/src/sym.rs b/src/tools/clippy/clippy_utils/src/sym.rs index 492eb89708aeb..6a7637fb18585 100644 --- a/src/tools/clippy/clippy_utils/src/sym.rs +++ b/src/tools/clippy/clippy_utils/src/sym.rs @@ -202,7 +202,6 @@ generate! { cx, cycle, cyclomatic_complexity, - dbg_macro, de, debug_struct, deprecated_in_future, diff --git a/src/tools/miri/tests/fail/dangling_pointers/dangling_primitive.stderr b/src/tools/miri/tests/fail/dangling_pointers/dangling_primitive.stderr index afc2cb214842e..4f06a1afa50fe 100644 --- a/src/tools/miri/tests/fail/dangling_pointers/dangling_primitive.stderr +++ b/src/tools/miri/tests/fail/dangling_pointers/dangling_primitive.stderr @@ -2,7 +2,7 @@ error: Undefined Behavior: memory access failed: ALLOC has been freed, so this p --> tests/fail/dangling_pointers/dangling_primitive.rs:LL:CC | LL | dbg!(*ptr); - | ^^^^^^^^^^ Undefined Behavior occurred here + | ^^^^ Undefined Behavior occurred here | = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information diff --git a/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr b/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr index 364a4b4a74418..88d5694c4736d 100644 --- a/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr +++ b/src/tools/miri/tests/fail/function_calls/return_pointer_on_unwind.stderr @@ -7,7 +7,7 @@ error: Undefined Behavior: reading memory at ALLOC[0x0..0x4], but memory is unin --> tests/fail/function_calls/return_pointer_on_unwind.rs:LL:CC | LL | dbg!(x.0); - | ^^^^^^^^^ Undefined Behavior occurred here + | ^^^ Undefined Behavior occurred here | = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information diff --git a/tests/ui/borrowck/dbg-issue-120327.stderr b/tests/ui/borrowck/dbg-issue-120327.stderr index b23c7ba5ebbbc..e7a7151e541dd 100644 --- a/tests/ui/borrowck/dbg-issue-120327.stderr +++ b/tests/ui/borrowck/dbg-issue-120327.stderr @@ -4,10 +4,14 @@ error[E0382]: use of moved value: `a` LL | let a = String::new(); | - move occurs because `a` has type `String`, which does not implement the `Copy` trait LL | dbg!(a); - | ------- value moved here + | - value moved here LL | return a; | ^ value used here after move | +help: consider cloning the value if the performance cost is acceptable + | +LL | dbg!(a.clone()); + | ++++++++ help: consider borrowing instead of transferring ownership | LL | dbg!(&a); @@ -19,10 +23,14 @@ error[E0382]: use of moved value: `a` LL | let a = String::new(); | - move occurs because `a` has type `String`, which does not implement the `Copy` trait LL | dbg!(1, 2, a, 1, 2); - | ------------------- value moved here + | - value moved here LL | return a; | ^ value used here after move | +help: consider cloning the value if the performance cost is acceptable + | +LL | dbg!(1, 2, a.clone(), 1, 2); + | ++++++++ help: consider borrowing instead of transferring ownership | LL | dbg!(1, 2, &a, 1, 2); @@ -34,10 +42,14 @@ error[E0382]: use of moved value: `b` LL | let b: String = "".to_string(); | - move occurs because `b` has type `String`, which does not implement the `Copy` trait LL | dbg!(a, b); - | ---------- value moved here + | - value moved here LL | return b; | ^ value used here after move | +help: consider cloning the value if the performance cost is acceptable + | +LL | dbg!(a, b.clone()); + | ++++++++ help: consider borrowing instead of transferring ownership | LL | dbg!(a, &b); @@ -50,42 +62,53 @@ LL | fn x(a: String) -> String { | - move occurs because `a` has type `String`, which does not implement the `Copy` trait LL | let b: String = "".to_string(); LL | dbg!(a, b); - | ---------- value moved here + | - value moved here LL | return a; | ^ value used here after move | +help: consider cloning the value if the performance cost is acceptable + | +LL | dbg!(a.clone(), b); + | ++++++++ help: consider borrowing instead of transferring ownership | LL | dbg!(&a, b); | + error[E0382]: use of moved value: `a` - --> $DIR/dbg-issue-120327.rs:33:12 + --> $DIR/dbg-issue-120327.rs:30:13 | LL | fn two_of_them(a: String) -> String { | - move occurs because `a` has type `String`, which does not implement the `Copy` trait LL | dbg!(a, a); - | ---------- value moved here -... -LL | return a; - | ^ value used here after move + | - ^ value used here after move + | | + | value moved here + | +help: consider cloning the value if the performance cost is acceptable | +LL | dbg!(a.clone(), a); + | ++++++++ help: consider borrowing instead of transferring ownership | -LL | dbg!(a, &a); - | + +LL | dbg!(&a, a); + | + error[E0382]: use of moved value: `a` - --> $DIR/dbg-issue-120327.rs:30:5 + --> $DIR/dbg-issue-120327.rs:33:12 | LL | fn two_of_them(a: String) -> String { | - move occurs because `a` has type `String`, which does not implement the `Copy` trait LL | dbg!(a, a); - | ^^^^^^^^^^ - | | - | value moved here - | value used here after move + | - value moved here +... +LL | return a; + | ^ value used here after move | +help: consider cloning the value if the performance cost is acceptable + | +LL | dbg!(a, a.clone()); + | ++++++++ help: consider borrowing instead of transferring ownership | LL | dbg!(a, &a); @@ -97,10 +120,14 @@ error[E0382]: borrow of moved value: `a` LL | let a: String = "".to_string(); | - move occurs because `a` has type `String`, which does not implement the `Copy` trait LL | let _res = get_expr(dbg!(a)); - | ------- value moved here + | - value moved here LL | let _l = a.len(); | ^ value borrowed here after move | +help: consider cloning the value if the performance cost is acceptable + | +LL | let _res = get_expr(dbg!(a.clone())); + | ++++++++ help: consider borrowing instead of transferring ownership | LL | let _res = get_expr(dbg!(&a)); diff --git a/tests/ui/liveness/liveness-upvars.rs b/tests/ui/liveness/liveness-upvars.rs index 1a3d0e5be54ad..06a7f7e9b0230 100644 --- a/tests/ui/liveness/liveness-upvars.rs +++ b/tests/ui/liveness/liveness-upvars.rs @@ -99,7 +99,7 @@ pub fn g(mut v: T) { } pub fn h() { - let mut z = T::default(); + let mut z = T::default(); //~ WARN unused variable: `z` let _ = move |b| { loop { if b { diff --git a/tests/ui/liveness/liveness-upvars.stderr b/tests/ui/liveness/liveness-upvars.stderr index b569acdccf8a7..f7bb6308bae5b 100644 --- a/tests/ui/liveness/liveness-upvars.stderr +++ b/tests/ui/liveness/liveness-upvars.stderr @@ -157,6 +157,14 @@ LL | z = T::default(); | = help: maybe it is overwritten before being read? +warning: unused variable: `z` + --> $DIR/liveness-upvars.rs:102:9 + | +LL | let mut z = T::default(); + | ^^^^^ help: if this is intentional, prefix it with an underscore: `_z` + | + = note: `#[warn(unused_variables)]` implied by `#[warn(unused)]` + warning: value captured by `state` is never read --> $DIR/liveness-upvars.rs:132:9 | @@ -198,5 +206,5 @@ LL | s = yield (); LL | s = 3; | ----- `s` is overwritten here before the previous value is read -warning: 24 warnings emitted +warning: 25 warnings emitted diff --git a/tests/ui/mismatched_types/mismatched-types-issue-126222.fixed b/tests/ui/mismatched_types/mismatched-types-issue-126222.fixed index 30fd0028f198f..d857a0f6c7761 100644 --- a/tests/ui/mismatched_types/mismatched-types-issue-126222.fixed +++ b/tests/ui/mismatched_types/mismatched-types-issue-126222.fixed @@ -12,7 +12,7 @@ fn main() { fn mismatch_types2() -> i32 { match 2 { x => { - return dbg!(x) //~ ERROR mismatched types + return dbg!(x); //~ ERROR mismatched types } } todo!() @@ -27,7 +27,7 @@ fn main() { fn mismatch_types4() -> i32 { match 1 { - _ => {return dbg!(1)} //~ ERROR mismatched types + _ => {return dbg!(1);} //~ ERROR mismatched types } todo!() } diff --git a/tests/ui/mismatched_types/mismatched-types-issue-126222.stderr b/tests/ui/mismatched_types/mismatched-types-issue-126222.stderr index 09ba15253dc58..ca38d8324c989 100644 --- a/tests/ui/mismatched_types/mismatched-types-issue-126222.stderr +++ b/tests/ui/mismatched_types/mismatched-types-issue-126222.stderr @@ -1,8 +1,11 @@ error[E0308]: mismatched types --> $DIR/mismatched-types-issue-126222.rs:7:18 | -LL | x => dbg!(x), - | ^^^^^^^ expected `()`, found integer +LL | / match 1 { +LL | | x => dbg!(x), + | | ^^^^^^^ expected `()`, found integer +LL | | } + | |_________- expected this to be `()` | help: you might have meant to return this value | @@ -12,19 +15,27 @@ LL | x => return dbg!(x), error[E0308]: mismatched types --> $DIR/mismatched-types-issue-126222.rs:15:17 | -LL | dbg!(x) - | ^^^^^^^ expected `()`, found integer +LL | / match 2 { +LL | | x => { +LL | | dbg!(x) + | | ^^^^^^^ expected `()`, found integer +LL | | } +LL | | } + | |_________- expected this to be `()` | help: you might have meant to return this value | -LL | return dbg!(x) - | ++++++ +LL | return dbg!(x); + | ++++++ + error[E0308]: mismatched types --> $DIR/mismatched-types-issue-126222.rs:23:18 | -LL | _ => dbg!(1) - | ^^^^^^^ expected `()`, found integer +LL | / match 1 { +LL | | _ => dbg!(1) + | | ^^^^^^^ expected `()`, found integer +LL | | } + | |_________- expected this to be `()` | help: you might have meant to return this value | @@ -34,13 +45,16 @@ LL | _ => return dbg!(1) error[E0308]: mismatched types --> $DIR/mismatched-types-issue-126222.rs:30:19 | -LL | _ => {dbg!(1)} - | ^^^^^^^ expected `()`, found integer +LL | / match 1 { +LL | | _ => {dbg!(1)} + | | ^^^^^^^ expected `()`, found integer +LL | | } + | |_________- expected this to be `()` | help: you might have meant to return this value | -LL | _ => {return dbg!(1)} - | ++++++ +LL | _ => {return dbg!(1);} + | ++++++ + error: aborting due to 4 previous errors diff --git a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-move-semantics.stderr b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-move-semantics.stderr index f8ef315b9cc78..7ce5ebf81e310 100644 --- a/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-move-semantics.stderr +++ b/tests/ui/rfcs/rfc-2361-dbg-macro/dbg-macro-move-semantics.stderr @@ -1,13 +1,21 @@ error[E0382]: use of moved value: `a` - --> $DIR/dbg-macro-move-semantics.rs:9:13 + --> $DIR/dbg-macro-move-semantics.rs:9:18 | LL | let a = NoCopy(0); | - move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait LL | let _ = dbg!(a); - | ------- value moved here + | - value moved here LL | let _ = dbg!(a); - | ^^^^^^^ value used here after move + | ^ value used here after move | +note: if `NoCopy` implemented `Clone`, you could clone the value + --> $DIR/dbg-macro-move-semantics.rs:4:1 + | +LL | struct NoCopy(usize); + | ^^^^^^^^^^^^^ consider implementing `Clone` for this type +... +LL | let _ = dbg!(a); + | - you could clone this value help: consider borrowing instead of transferring ownership | LL | let _ = dbg!(&a);