mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-23 21:23:56 +00:00
Update unnecessary_operation and no_effect to not suggest removing
structs/enums wrappers when that type implements Drop as noted in #2061.
This commit is contained in:
Chris Emerson
parent
2bb8efdb4d
commit
f680eb164d
3 changed files with 259 additions and 209 deletions
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@ -40,12 +40,22 @@ declare_lint! {
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"outer expressions with no effect"
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}
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/// Check whether this type implements Drop.
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fn has_drop(cx: &LateContext, expr: &Expr) -> bool {
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let struct_ty = cx.tables.expr_ty(expr);
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match struct_ty.ty_adt_def() {
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Some(def) => def.has_dtor(cx.tcx),
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_ => false,
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}
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}
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fn has_no_effect(cx: &LateContext, expr: &Expr) -> bool {
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if in_macro(expr.span) {
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return false;
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}
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match expr.node {
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Expr_::ExprLit(..) | Expr_::ExprClosure(.., _) | Expr_::ExprPath(..) => true,
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Expr_::ExprLit(..) | Expr_::ExprClosure(.., _) => true,
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Expr_::ExprPath(..) => !has_drop(cx, expr),
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Expr_::ExprIndex(ref a, ref b) | Expr_::ExprBinary(_, ref a, ref b) => {
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has_no_effect(cx, a) && has_no_effect(cx, b)
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},
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@ -59,7 +69,7 @@ fn has_no_effect(cx: &LateContext, expr: &Expr) -> bool {
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Expr_::ExprAddrOf(_, ref inner) |
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Expr_::ExprBox(ref inner) => has_no_effect(cx, inner),
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Expr_::ExprStruct(_, ref fields, ref base) => {
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fields.iter().all(|field| has_no_effect(cx, &field.expr)) && match *base {
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!has_drop(cx, expr) && fields.iter().all(|field| has_no_effect(cx, &field.expr)) && match *base {
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Some(ref base) => has_no_effect(cx, base),
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None => true,
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}
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@ -68,7 +78,7 @@ fn has_no_effect(cx: &LateContext, expr: &Expr) -> bool {
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let def = cx.tables.qpath_def(qpath, callee.hir_id);
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match def {
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Def::Struct(..) | Def::Variant(..) | Def::StructCtor(..) | Def::VariantCtor(..) => {
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args.iter().all(|arg| has_no_effect(cx, arg))
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!has_drop(cx, expr) && args.iter().all(|arg| has_no_effect(cx, arg))
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},
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_ => false,
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}
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@ -145,18 +155,23 @@ fn reduce_expression<'a>(cx: &LateContext, expr: &'a Expr) -> Option<Vec<&'a Exp
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Expr_::ExprTupField(ref inner, _) |
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Expr_::ExprAddrOf(_, ref inner) |
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Expr_::ExprBox(ref inner) => reduce_expression(cx, inner).or_else(|| Some(vec![inner])),
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Expr_::ExprStruct(_, ref fields, ref base) => Some(
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Expr_::ExprStruct(_, ref fields, ref base) => {
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if has_drop(cx, expr) {
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None
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} else {
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Some(
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fields
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.iter()
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.map(|f| &f.expr)
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.chain(base)
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.map(Deref::deref)
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.collect(),
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),
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.collect())
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}
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},
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Expr_::ExprCall(ref callee, ref args) => if let Expr_::ExprPath(ref qpath) = callee.node {
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let def = cx.tables.qpath_def(qpath, callee.hir_id);
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match def {
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Def::Struct(..) | Def::Variant(..) | Def::StructCtor(..) | Def::VariantCtor(..) => {
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Def::Struct(..) | Def::Variant(..) | Def::StructCtor(..) | Def::VariantCtor(..) if !has_drop(cx, expr) => {
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Some(args.iter().collect())
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},
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_ => None,
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@ -16,6 +16,27 @@ enum Enum {
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Tuple(i32),
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Struct { field: i32 },
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}
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struct DropUnit;
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impl Drop for DropUnit {
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fn drop(&mut self) {}
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}
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struct DropStruct {
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field: i32
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}
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impl Drop for DropStruct {
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fn drop(&mut self) {}
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}
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struct DropTuple(i32);
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impl Drop for DropTuple {
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fn drop(&mut self) {}
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}
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enum DropEnum {
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Tuple(i32),
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Struct { field: i32 },
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}
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impl Drop for DropEnum {
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fn drop(&mut self) {}
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}
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union Union {
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a: u8,
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@ -24,6 +45,7 @@ union Union {
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fn get_number() -> i32 { 0 }
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fn get_struct() -> Struct { Struct { field: 0 } }
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fn get_drop_struct() -> DropStruct { DropStruct { field: 0 } }
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unsafe fn unsafe_fn() -> i32 { 0 }
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@ -61,6 +83,11 @@ fn main() {
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// Do not warn
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get_number();
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unsafe { unsafe_fn() };
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DropUnit;
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DropStruct { field: 0 };
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DropTuple(0);
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DropEnum::Tuple(0);
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DropEnum::Struct { field: 0 };
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Tuple(get_number());
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Struct { field: get_number() };
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@ -81,4 +108,12 @@ fn main() {
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[get_number(); 55];
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[42; 55][get_number() as usize];
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{get_number()};
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// Do not warn
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DropTuple(get_number());
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DropStruct { field: get_number() };
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DropStruct { field: get_number() };
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DropStruct { ..get_drop_struct() };
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DropEnum::Tuple(get_number());
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DropEnum::Struct { field: get_number() };
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}
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@ -1,269 +1,269 @@
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error: statement with no effect
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--> $DIR/no_effect.rs:34:5
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--> $DIR/no_effect.rs:56:5
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34 | 0;
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56 | 0;
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| ^^
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= note: `-D no-effect` implied by `-D warnings`
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error: statement with no effect
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--> $DIR/no_effect.rs:35:5
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35 | s2;
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| ^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:36:5
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36 | Unit;
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| ^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:37:5
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37 | Tuple(0);
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| ^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:38:5
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38 | Struct { field: 0 };
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| ^^^^^^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:39:5
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39 | Struct { ..s };
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| ^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:40:5
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40 | Union { a: 0 };
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| ^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:41:5
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41 | Enum::Tuple(0);
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| ^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:42:5
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42 | Enum::Struct { field: 0 };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:43:5
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43 | 5 + 6;
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| ^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:44:5
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44 | *&42;
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| ^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:45:5
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45 | &6;
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| ^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:46:5
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46 | (5, 6, 7);
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| ^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:47:5
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47 | box 42;
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| ^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:48:5
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48 | ..;
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| ^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:49:5
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49 | 5..;
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| ^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:50:5
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50 | ..5;
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| ^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:51:5
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51 | 5..6;
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| ^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:52:5
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52 | 5...6;
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| ^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:53:5
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53 | [42, 55];
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| ^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:54:5
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54 | [42, 55][1];
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| ^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:55:5
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55 | (42, 55).1;
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| ^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:56:5
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56 | [42; 55];
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| ^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:57:5
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57 | [42; 55][13];
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| ^^^^^^^^^^^^^
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57 | s2;
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| ^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:58:5
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58 | Unit;
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| ^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:59:5
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59 | || x += 5;
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59 | Tuple(0);
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| ^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:60:5
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60 | Struct { field: 0 };
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| ^^^^^^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:61:5
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61 | Struct { ..s };
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| ^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:62:5
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62 | Union { a: 0 };
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| ^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:63:5
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63 | Enum::Tuple(0);
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| ^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:64:5
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64 | Enum::Struct { field: 0 };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:65:5
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65 | 5 + 6;
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| ^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:66:5
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66 | *&42;
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| ^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:67:5
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67 | &6;
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| ^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:68:5
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68 | (5, 6, 7);
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| ^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:69:5
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69 | box 42;
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| ^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:70:5
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70 | ..;
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| ^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:71:5
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71 | 5..;
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| ^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:72:5
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|
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72 | ..5;
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| ^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:73:5
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|
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73 | 5..6;
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| ^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:74:5
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|
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74 | 5...6;
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| ^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:75:5
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|
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75 | [42, 55];
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| ^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:76:5
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|
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76 | [42, 55][1];
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| ^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:77:5
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|
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77 | (42, 55).1;
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| ^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:78:5
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|
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78 | [42; 55];
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| ^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:79:5
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|
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79 | [42; 55][13];
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| ^^^^^^^^^^^^^
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error: statement with no effect
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--> $DIR/no_effect.rs:81:5
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|
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81 | || x += 5;
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| ^^^^^^^^^^
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error: statement can be reduced
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--> $DIR/no_effect.rs:65:5
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--> $DIR/no_effect.rs:92:5
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|
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65 | Tuple(get_number());
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92 | Tuple(get_number());
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| ^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
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|
|
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= note: `-D unnecessary-operation` implied by `-D warnings`
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:66:5
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--> $DIR/no_effect.rs:93:5
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|
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66 | Struct { field: get_number() };
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93 | Struct { field: get_number() };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:67:5
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--> $DIR/no_effect.rs:94:5
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|
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67 | Struct { ..get_struct() };
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94 | Struct { ..get_struct() };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_struct();`
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:68:5
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--> $DIR/no_effect.rs:95:5
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|
|
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68 | Enum::Tuple(get_number());
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95 | Enum::Tuple(get_number());
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
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|
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error: statement can be reduced
|
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--> $DIR/no_effect.rs:69:5
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--> $DIR/no_effect.rs:96:5
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|
|
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69 | Enum::Struct { field: get_number() };
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96 | Enum::Struct { field: get_number() };
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
|
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|
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error: statement can be reduced
|
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--> $DIR/no_effect.rs:70:5
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--> $DIR/no_effect.rs:97:5
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|
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70 | 5 + get_number();
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97 | 5 + get_number();
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| ^^^^^^^^^^^^^^^^^ help: replace it with: `5;get_number();`
|
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:71:5
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--> $DIR/no_effect.rs:98:5
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|
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71 | *&get_number();
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98 | *&get_number();
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| ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:72:5
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--> $DIR/no_effect.rs:99:5
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|
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72 | &get_number();
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99 | &get_number();
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| ^^^^^^^^^^^^^^ help: replace it with: `get_number();`
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:73:5
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--> $DIR/no_effect.rs:100:5
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|
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73 | (5, 6, get_number());
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100 | (5, 6, get_number());
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| ^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `5;6;get_number();`
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|
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error: statement can be reduced
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--> $DIR/no_effect.rs:74:5
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--> $DIR/no_effect.rs:101:5
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|
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74 | box get_number();
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101 | box get_number();
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| ^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
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error: statement can be reduced
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--> $DIR/no_effect.rs:75:5
|
||||
--> $DIR/no_effect.rs:102:5
|
||||
|
|
||||
75 | get_number()..;
|
||||
102 | get_number()..;
|
||||
| ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:76:5
|
||||
--> $DIR/no_effect.rs:103:5
|
||||
|
|
||||
76 | ..get_number();
|
||||
103 | ..get_number();
|
||||
| ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:77:5
|
||||
--> $DIR/no_effect.rs:104:5
|
||||
|
|
||||
77 | 5..get_number();
|
||||
104 | 5..get_number();
|
||||
| ^^^^^^^^^^^^^^^^ help: replace it with: `5;get_number();`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:78:5
|
||||
--> $DIR/no_effect.rs:105:5
|
||||
|
|
||||
78 | [42, get_number()];
|
||||
105 | [42, get_number()];
|
||||
| ^^^^^^^^^^^^^^^^^^^ help: replace it with: `42;get_number();`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:79:5
|
||||
--> $DIR/no_effect.rs:106:5
|
||||
|
|
||||
79 | [42, 55][get_number() as usize];
|
||||
106 | [42, 55][get_number() as usize];
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `[42, 55];get_number() as usize;`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:80:5
|
||||
--> $DIR/no_effect.rs:107:5
|
||||
|
|
||||
80 | (42, get_number()).1;
|
||||
107 | (42, get_number()).1;
|
||||
| ^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `42;get_number();`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:81:5
|
||||
--> $DIR/no_effect.rs:108:5
|
||||
|
|
||||
81 | [get_number(); 55];
|
||||
108 | [get_number(); 55];
|
||||
| ^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:82:5
|
||||
--> $DIR/no_effect.rs:109:5
|
||||
|
|
||||
82 | [42; 55][get_number() as usize];
|
||||
109 | [42; 55][get_number() as usize];
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `[42; 55];get_number() as usize;`
|
||||
|
||||
error: statement can be reduced
|
||||
--> $DIR/no_effect.rs:83:5
|
||||
--> $DIR/no_effect.rs:110:5
|
||||
|
|
||||
83 | {get_number()};
|
||||
110 | {get_number()};
|
||||
| ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
|
||||
|
||||
error: aborting due to 44 previous errors
|
||||
|
|
|
|||
Loading…
Reference in a new issue