diff options
| -rw-r--r-- | compiler/rustc_lint/src/unused.rs | 13 | ||||
| -rw-r--r-- | src/test/ui/lint/fn_must_use.stderr | 8 | ||||
| -rw-r--r-- | src/test/ui/lint/must-use-ops.stderr | 83 | ||||
| -rw-r--r-- | src/test/ui/lint/unused-borrows.stderr | 23 | ||||
| -rw-r--r-- | src/test/ui/unused/issue-85913.rs | 13 | ||||
| -rw-r--r-- | src/test/ui/unused/issue-85913.stderr | 15 |
6 files changed, 125 insertions, 30 deletions
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs index c431c048ca0..5437174a683 100644 --- a/compiler/rustc_lint/src/unused.rs +++ b/compiler/rustc_lint/src/unused.rs @@ -161,7 +161,18 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { if let Some(must_use_op) = must_use_op { cx.struct_span_lint(UNUSED_MUST_USE, expr.span, |lint| { - lint.build(&format!("unused {} that must be used", must_use_op)).emit() + let mut lint = lint.build(&format!("unused {} that must be used", must_use_op)); + lint.note(&format!("the {} produces a value", must_use_op)); + if let Ok(snippet) = cx.sess().source_map().span_to_snippet(expr.span) { + lint.span_suggestion( + expr.span, + "use `let _ = ...` to ignore it", + format!("let _ = {}", snippet), + Applicability::MachineApplicable, + ) + .emit() + } + lint.emit(); }); op_warned = true; } diff --git a/src/test/ui/lint/fn_must_use.stderr b/src/test/ui/lint/fn_must_use.stderr index d6b1cf3ae1f..75a22823329 100644 --- a/src/test/ui/lint/fn_must_use.stderr +++ b/src/test/ui/lint/fn_must_use.stderr @@ -47,13 +47,17 @@ warning: unused comparison that must be used --> $DIR/fn_must_use.rs:74:5 | LL | 2 == 3; - | ^^^^^^ + | ^^^^^^ help: use `let _ = ...` to ignore it: `let _ = 2 == 3` + | + = note: the comparison produces a value warning: unused comparison that must be used --> $DIR/fn_must_use.rs:75:5 | LL | m == n; - | ^^^^^^ + | ^^^^^^ help: use `let _ = ...` to ignore it: `let _ = m == n` + | + = note: the comparison produces a value warning: 8 warnings emitted diff --git a/src/test/ui/lint/must-use-ops.stderr b/src/test/ui/lint/must-use-ops.stderr index 3fb80f7e798..73405d02a2e 100644 --- a/src/test/ui/lint/must-use-ops.stderr +++ b/src/test/ui/lint/must-use-ops.stderr @@ -2,133 +2,174 @@ warning: unused comparison that must be used --> $DIR/must-use-ops.rs:12:5 | LL | val == 1; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val == 1` | note: the lint level is defined here --> $DIR/must-use-ops.rs:5:9 | LL | #![warn(unused_must_use)] | ^^^^^^^^^^^^^^^ + = note: the comparison produces a value warning: unused comparison that must be used --> $DIR/must-use-ops.rs:13:5 | LL | val < 1; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val < 1` + | + = note: the comparison produces a value warning: unused comparison that must be used --> $DIR/must-use-ops.rs:14:5 | LL | val <= 1; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val <= 1` + | + = note: the comparison produces a value warning: unused comparison that must be used --> $DIR/must-use-ops.rs:15:5 | LL | val != 1; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val != 1` + | + = note: the comparison produces a value warning: unused comparison that must be used --> $DIR/must-use-ops.rs:16:5 | LL | val >= 1; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val >= 1` + | + = note: the comparison produces a value warning: unused comparison that must be used --> $DIR/must-use-ops.rs:17:5 | LL | val > 1; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val > 1` + | + = note: the comparison produces a value warning: unused arithmetic operation that must be used --> $DIR/must-use-ops.rs:20:5 | LL | val + 2; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val + 2` + | + = note: the arithmetic operation produces a value warning: unused arithmetic operation that must be used --> $DIR/must-use-ops.rs:21:5 | LL | val - 2; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val - 2` + | + = note: the arithmetic operation produces a value warning: unused arithmetic operation that must be used --> $DIR/must-use-ops.rs:22:5 | LL | val / 2; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val / 2` + | + = note: the arithmetic operation produces a value warning: unused arithmetic operation that must be used --> $DIR/must-use-ops.rs:23:5 | LL | val * 2; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val * 2` + | + = note: the arithmetic operation produces a value warning: unused arithmetic operation that must be used --> $DIR/must-use-ops.rs:24:5 | LL | val % 2; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = val % 2` + | + = note: the arithmetic operation produces a value warning: unused logical operation that must be used --> $DIR/must-use-ops.rs:27:5 | LL | true && true; - | ^^^^^^^^^^^^ + | ^^^^^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = true && true` + | + = note: the logical operation produces a value warning: unused logical operation that must be used --> $DIR/must-use-ops.rs:28:5 | LL | false || true; - | ^^^^^^^^^^^^^ + | ^^^^^^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = false || true` + | + = note: the logical operation produces a value warning: unused bitwise operation that must be used --> $DIR/must-use-ops.rs:31:5 | LL | 5 ^ val; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = 5 ^ val` + | + = note: the bitwise operation produces a value warning: unused bitwise operation that must be used --> $DIR/must-use-ops.rs:32:5 | LL | 5 & val; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = 5 & val` + | + = note: the bitwise operation produces a value warning: unused bitwise operation that must be used --> $DIR/must-use-ops.rs:33:5 | LL | 5 | val; - | ^^^^^^^ + | ^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = 5 | val` + | + = note: the bitwise operation produces a value warning: unused bitwise operation that must be used --> $DIR/must-use-ops.rs:34:5 | LL | 5 << val; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = 5 << val` + | + = note: the bitwise operation produces a value warning: unused bitwise operation that must be used --> $DIR/must-use-ops.rs:35:5 | LL | 5 >> val; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = 5 >> val` + | + = note: the bitwise operation produces a value warning: unused unary operation that must be used --> $DIR/must-use-ops.rs:38:5 | LL | !val; - | ^^^^ + | ^^^^ help: use `let _ = ...` to ignore it: `let _ = !val` + | + = note: the unary operation produces a value warning: unused unary operation that must be used --> $DIR/must-use-ops.rs:39:5 | LL | -val; - | ^^^^ + | ^^^^ help: use `let _ = ...` to ignore it: `let _ = -val` + | + = note: the unary operation produces a value warning: unused unary operation that must be used --> $DIR/must-use-ops.rs:40:5 | LL | *val_pointer; - | ^^^^^^^^^^^^ + | ^^^^^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = *val_pointer` + | + = note: the unary operation produces a value warning: 21 warnings emitted diff --git a/src/test/ui/lint/unused-borrows.stderr b/src/test/ui/lint/unused-borrows.stderr index 24899fe992b..459381b642c 100644 --- a/src/test/ui/lint/unused-borrows.stderr +++ b/src/test/ui/lint/unused-borrows.stderr @@ -2,43 +2,54 @@ error: unused borrow that must be used --> $DIR/unused-borrows.rs:6:5 | LL | &42; - | ^^^ + | ^^^ help: use `let _ = ...` to ignore it: `let _ = &42` | note: the lint level is defined here --> $DIR/unused-borrows.rs:1:9 | LL | #![deny(unused_must_use)] | ^^^^^^^^^^^^^^^ + = note: the borrow produces a value error: unused borrow that must be used --> $DIR/unused-borrows.rs:9:5 | LL | &mut foo(42); - | ^^^^^^^^^^^^ + | ^^^^^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = &mut foo(42)` + | + = note: the borrow produces a value error: unused borrow that must be used --> $DIR/unused-borrows.rs:12:5 | LL | &&42; - | ^^^^ + | ^^^^ help: use `let _ = ...` to ignore it: `let _ = &&42` + | + = note: the borrow produces a value error: unused borrow that must be used --> $DIR/unused-borrows.rs:15:5 | LL | &&mut 42; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = &&mut 42` + | + = note: the borrow produces a value error: unused borrow that must be used --> $DIR/unused-borrows.rs:18:5 | LL | &mut &42; - | ^^^^^^^^ + | ^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = &mut &42` + | + = note: the borrow produces a value error: unused borrow that must be used --> $DIR/unused-borrows.rs:23:5 | LL | && foo(42); - | ^^^^^^^^^^ + | ^^^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = && foo(42)` + | + = note: the borrow produces a value error: aborting due to 6 previous errors diff --git a/src/test/ui/unused/issue-85913.rs b/src/test/ui/unused/issue-85913.rs new file mode 100644 index 00000000000..7f3817b6ef1 --- /dev/null +++ b/src/test/ui/unused/issue-85913.rs @@ -0,0 +1,13 @@ +#![deny(unused_must_use)] + +pub fn fun() -> i32 { + function() && return 1; + //~^ ERROR: unused logical operation that must be used + return 0; +} + +fn function() -> bool { + true +} + +fn main() {} diff --git a/src/test/ui/unused/issue-85913.stderr b/src/test/ui/unused/issue-85913.stderr new file mode 100644 index 00000000000..d5d99f0f7d3 --- /dev/null +++ b/src/test/ui/unused/issue-85913.stderr @@ -0,0 +1,15 @@ +error: unused logical operation that must be used + --> $DIR/issue-85913.rs:4:5 + | +LL | function() && return 1; + | ^^^^^^^^^^^^^^^^^^^^^^ help: use `let _ = ...` to ignore it: `let _ = function() && return 1` + | +note: the lint level is defined here + --> $DIR/issue-85913.rs:1:9 + | +LL | #![deny(unused_must_use)] + | ^^^^^^^^^^^^^^^ + = note: the logical operation produces a value + +error: aborting due to previous error + |